title: Videotelephony

text: Although not as widely used in everyday communications as audio-only and text communication, useful applications include sign language transmission for deaf and speech-impaired people, distance education, telemedicine, and overcoming mobility issues. It is also used in commercial and corporate settings to facilitate meetings and conferences, typically between parties that already have established relationships. News media organisations have begun to use desktop technologies like Skype to provide higher-quality audio than the cellular phone network, and video links at much lower cost than sending professional equipment or using a professional studio. More popular videotelephony technologies use the Internet rather than the traditional landline phone network, even though modern phone networks use digital packet protocols, and videotelephony software commonly runs on smartphones over digital radiotelephony networks.


title: Videotelephony

text: The concept of videotelephony was first conceived in the late 1870s, both in the United States and in Europe, although the basic sciences to permit its very earliest trials would take nearly a half century to be discovered. This was first embodied in the device which came to be known as the video telephone, or videophone, and it evolved from intensive research and experimentation in several telecommunication fields, notably electrical telegraphy, telephony, radio, and television.


title: Videotelephony

text: Simple analog videophone communication could be established as early as the invention of the television. Such an antecedent usually consisted of two closed-circuit television systems connected via coax cable or radio. An example of that was the German Reich Postzentralamt (post office) videotelephone network serving Berlin and several German cities via coaxial cables between 1936 and 1940.


title: Videotelephony

text: The development of videoconferencing as a subscription service started in the latter half of the 1920s in the United Kingdom and the United States, spurred notably by John Logie Baird and AT&T's Bell Labs. This occurred in part, at least with AT&T, to serve as an adjunct supplementing the use of the telephone. A number of organizations believed that videotelephony would be superior to plain voice communications. Attempts at using normal telephony networks to transmit slow-scan video, such as the first systems developed by AT&T Corporation, first researched in the 1950s, failed mostly due to the poor picture quality and the lack of efficient video compression techniques.


title: Videotelephony

text: During the first crewed space flights, NASA used two radio-frequency (UHF or VHF) video links, one in each direction. TV channels routinely use this type of videotelephony when reporting from distant locations. The news media were to become regular users of mobile links to satellites using specially equipped trucks, and much later via special satellite videophones in a briefcase. This technique was very expensive, though, and could not be used for applications such as telemedicine, distance education, and business meetings.


title: Videotelephony

text: Decades of research and development culminated in the 1970 commercial launch of AT&T's Picturephone service, available in select cities. However, the system was a commercial failure, chiefly due to consumer apathy, high subscription costs, and lack of network effect—with only a few hundred Picturephones in the world, users had extremely few contacts they could actually call, and interoperability with other videophone systems would not exist for decades.


title: Videotelephony

text: Very expensive videoconferencing systems continued to evolve throughout the 1980s and 1990s. Proprietary equipment, software, and network requirements gave way to standards-based technologies that were available for anyone to purchase at a reasonable cost. Only in the late 20th century with the advent of powerful video codecs combined with high-speed Internet broadband and ISDN service did videotelephony become a practical technology for regular use.


title: Videotelephony

text: Advances in video compression allowed digital video streams to be transmitted over the Internet, which was previously difficult due to the impractically high bandwidth requirements of uncompressed video. To achieve Video Graphics Array (VGA) quality video (480p resolution and 256 colors) with raw uncompressed video, it would require a bandwidth of over 92Mbps. A common compression technique used to significantly reduce bandwidth requirements in videotelephony and videoconferencing is the discrete cosine transform (DCT), developed by Nasir Ahmed, T. Natarajan and K. R. Rao in 1973. The DCT algorithm was the basis for the first practical video coding standard that was useful for online videoconferencing, H.261, standardised by the ITU-T in 1988, and subsequent H.26x video coding standards.


title: Videotelephony

text: In the 1980s, digital telephony transmission networks became possible, such as with ISDN networks, assuring a minimum bit rate (usually 128 kilobits/s) for compressed video and audio transmission. During this time, there was also research into other forms of digital video and audio communication. Many of these technologies, such as the Media space, are not as widely used today as videoconferencing but were still an important area of research. The first dedicated systems started to appear as ISDN networks were expanding throughout the world. One of the first commercial videoconferencing systems sold to companies came from PictureTel Corp., which had an initial public offering in November, 1984.


title: Videotelephony

text: In 1984, Concept Communication in the United States replaced the , US$100,000 computers necessary for teleconferencing, with a $12,000 circuit board that doubled the video frame rate from 15 to 30 frames per second, and which reduced the equipment to the size of a circuit board fitting into standard personal computers. The company also secured a patent for a codec for full-motion videoconferencing, first demonstrated at AT&T Bell Labs in 1986.


title: Videotelephony

text: Videoconferencing systems throughout the 1990s rapidly evolved from very expensive proprietary equipment, software, and network requirements to a standards-based technology readily available to the general public at a reasonable cost.


title: Videotelephony

text: Finally, in the 1990s, Internet Protocol-based videoconferencing became possible, and more efficient video compression technologies were developed, permitting desktop, or personal computer (PC)-based videoconferencing. In 1992 CU-SeeMe was developed at Cornell by Tim Dorcey et al. In 1995 the first public videoconference between North America and Africa took place, linking a technofair in San Francisco with a techno-rave and cyberdeli in Cape Town. At the 1998 Winter Olympics opening ceremony in Nagano, Japan, Seiji Ozawa conducted the Ode to Joy from Beethoven's Ninth Symphony simultaneously across five continents in near-real-time.


title: Videotelephony

text: While videoconferencing technology was initially used primarily within internal corporate communication networks, one of the first community service uses of the technology started in 1992 through a unique partnership with PictureTel and IBM, which at the time were promoting a jointly developed desktop based videoconferencing product known as the PCS/1. Over the next 15 years, Project DIANE (Diversified Information and Assistance Network) grew to use a variety of videoconferencing platforms to create a multi-state cooperative public service and distance education network consisting of several hundred schools, libraries, science museums, zoos and parks, and many other community oriented organizations.


title: Videotelephony

text: Kyocera conducted a two-year development campaign from 1997 to 1999 that resulted in the release of the VP-210 Visual Phone, the first mobile colour videophone that also doubled as a camera phone for still photos. The camera phone was the same size as similar contemporary mobile phones, but sported a large camera lens and a 5 cm (2 inch) colour TFT display capable of displaying 65,000 colors, and was able to process two video frames per second.


title: Videotelephony

text: Videotelephony was popularized in the 2000s, via free Internet services such as Skype and iChat, web plugins supporting H.26x video standards, and on-line telecommunication programs that promoted low cost, albeit lower quality, videoconferencing to virtually every location with an Internet connection.


title: Videotelephony

text: With the rapid improvements and popularity of the Internet, videotelephony has become widespread through the deployment of video-enabled mobile phones such as 2010's iPhone 4, plus videoconferencing and computer webcams which use Internet telephony. In the upper echelons of government, business, and commerce, telepresence technology, an advanced form of videoconferencing, has helped reduce the need to travel.


title: Videotelephony

text: In May 2005, the first high definition videoconferencing systems, produced by LifeSize Communications, were displayed at the Interop trade show in Las Vegas, Nevada, able to provide video at 30 frames per second with a 1280 by 720 display resolution. Polycom introduced its first high definition videoconferencing system to the market in 2006. As of the 2010s, high definition resolution for videoconferencing became a popular feature, with most major suppliers in the videoconferencing market offering it.


title: Videotelephony

text: Technological developments by videoconferencing developers in the 2010s have extended the capabilities of videoconferencing systems beyond the boardroom for use with hand-held mobile devices that combine the use of video, audio and on-screen drawing capabilities broadcasting in real time over secure networks, independent of location. Mobile collaboration systems now allow people in previously unreachable locations, such as workers on an offshore oil rig, the ability to view and discuss issues with colleagues thousands of miles away. Traditional videoconferencing system manufacturers have begun providing mobile applications as well, such as those that allow for live and still image streaming.


title: Videotelephony

text: The highest ever video call (other than those from aircraft and spacecraft) took place on May 19, 2013, when British adventurer Daniel Hughes used a smartphone with a BGAN satellite modem to make a videocall to the BBC from the summit of Mount Everest, at above sea level.


title: Videotelephony

text: The COVID-19 pandemic resulted in a significant increase in the use of videoconferencing. Berstein Research found that Zoom added more subscribers during the first two months of 2020 alone than in the entire year 2019. GoToMeeting had a 20 percent increase in usage, according to LogMeIn. UK based StarLeaf reported a 600 percent increase in national call volumes. Videoconferencing became so widespread during the pandemic that the term "Zoom fatigue" came to prominence, referring to the taxing nature of spending long periods of time on videocalls.


title: Videotelephony

text: On 21 September 2021, Facebook launched two new versions of its Portal video-calling devices, the Portal Go and Portal Plus. The new video calling devices include the first portable variety of the hardware and number of updates.


title: Videotelephony

text: Videotelephony can be categorized by its functionality and intended purpose, and also by its method of transmission.


title: Videotelephony

text: Videophones were the earliest form of videotelephony, dating back to initial tests in 1927 by AT&T. During the late 1930s, the post offices of several European governments established public videophone services for person-to-person communications using dual cable circuit telephone transmission technology. In the present day, standalone videophones and UMTS video-enabled mobile phones are usually used on a person-to-person basis.


title: Videotelephony

text: Videoconferencing saw its earliest use with AT&T's Picturephone service in the early 1970s. Transmissions were analog over short distances, but converted to digital forms for longer calls, again using telephone transmission technology. Popular corporate video-conferencing systems in the present day have migrated almost exclusively to digital ISDN and IP transmission modes due to the need to convey the very large amounts of data generated by their cameras and microphones. These systems are often intended for use in conference mode, that is by many people in several different locations, all of whom can be viewed by every participant at each location.


title: Videotelephony

text: Telepresence systems are a newer, more advanced subset of videoconferencing systems, meant to allow higher degrees of video and audio fidelity. Such high-end systems are typically deployed in corporate settings.


title: Videotelephony

text: Mobile collaboration systems are another recent development, combining the use of video, audio, and on-screen drawing capabilities using newest generation hand-held electronic devices broadcasting over secure networks, enabling multi-party conferencing in real time, independent of location. Proximity chat is another alternative mode, focused on the flexibility of small group conversations.


title: Videotelephony

text: A more recent technology encompassing these functions is TV cams. TV cams enable people to make video "phone" calls using video calling services, like Skype on their TV, without using a PC connection. TV cams are specially designed video cameras that feed images in real time to another TV camera or other compatible computing devices like smartphones, tablets and computers.


title: Videotelephony

text: "Webcams" are popular, relatively low cost devices which can provide live video and audio streams via personal computers, and can be used with many software clients for both video calls and videoconferencing.


title: Videotelephony

text: Each of the systems has its own advantages and disadvantages, including video quality, capital cost, degrees of sophistication, transmission capacity requirements, and cost of use.


title: Videotelephony

text: Computer security experts have shown that poorly configured or inadequately supervised videoconferencing systems can permit an easy "virtual" entry by computer hackers and criminals into company premises and corporate boardrooms.


title: Videotelephony

text: For over a century, futurists have envisioned a future where telephone conversations will take place as actual face-to-face encounters with video as well as audio. Sometimes it is simply not possible or practical to have face-to-face meetings with two or more people. Sometimes a telephone conversation or conference call is adequate. Other times, e-mail exchanges are adequate. However, videoconferencing adds another option, and can be considered when:


title: Videotelephony

text: Bill Gates said in 2001 that he used videoconferencing "three or four times a year", because digital scheduling was difficult and "if the overhead is super high, then you might as well just have a face-to-face meeting". Some observers argue that three outstanding issues have prevented videoconferencing from becoming a widely adopted form of communication, despite the ubiquity of videoconferencing-capable systems.


title: Videotelephony

text: These are some of the reasons many organizations only use the systems internally, where there is less risk of loss of customers. An alternative for those lacking dedicated facilities is the rental of videoconferencing-equipped meeting rooms in cities around the world. Clients can book rooms and turn up for the meeting, with all technical aspects being prearranged and support being readily available if needed. The issue of eye-contact may be solved with advancing technology, including smartphones which have the screen and camera in essentially the same place. In developed countries, the near-ubiquity of smartphones, tablet computers, and computers with built-in audio and webcams removes the need for expensive dedicated hardware.


title: Videotelephony

text: The core technology used in a videotelephony system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labeled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP).


title: Videotelephony

text: "Continuous Presence" simply displays all participants at the same time, usually with the exception that the viewer either does not see their own feed, or sees their own feed in miniature.


title: Videotelephony

text: "Voice-Activated Switch" selectively chooses a feed to display at each endpoint, with the goal of showing the person who is currently speaking. This is done by choosing the feed (other than the viewer) which has the loudest audio input (perhaps with some filtering to avoid switching for very short-lived volume spikes). Often if no remote parties are currently speaking, the feed with the last speaker remains on the screen.


title: Videotelephony

text: Acoustic echo cancellation (AEC) is a processing algorithm that uses the knowledge of audio output to monitor audio input and filter from it noises that echo back after some time delay. If unattended, these echoes can be re-amplified several times, leading to problems including:


title: Videotelephony

text: Echo cancellation is a processor-intensive task that usually works over a narrow range of sound delays.


title: Videotelephony

text: Videophones have historically employed a variety of transmission and reception bandwidths, which can be understood as data transmission speeds. The lower the transmission/reception bandwidth, the lower the data transfer rate, resulting in a progressively limited and poorer image quality (i.e. lower resolution and/or frame rate). Data transfer rates and live video image quality are related, but are also subject to other factors such as data compression techniques. Some early videophones employed very low data transmission rates with a resulting poor video quality.


title: Videotelephony

text: "Broadband bandwidth" is often called ""high-speed"", because it usually has a high rate of data transmission. In general, any connection of 256 kbit/s (0.256 Mbit/s) or greater is more concisely considered broadband Internet. The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) recommendation I.113 has defined broadband as a transmission capacity at 1.5 to 2Mbit/s. The Federal Communications Commission (United States) definition of broadband is 25 Mbit/s.


title: Videotelephony

text: Currently, adequate video for some purposes becomes possible at data rates lower than the ITU-T broadband definition, with rates of 768 kbit/s and 384 kbit/s used for some videoconferencing applications, and rates as low as 100 kbit/s used for videophones using H.264/MPEG-4 AVC compression protocols. The newer MPEG-4 video and audio compression format can deliver high-quality video at 2Mbit/s, which is at the low end of cable modem and ADSL broadband performance.


title: Videotelephony

text: The International Telecommunication Union (ITU) has three umbrellas of standards for videoconferencing:


title: Videotelephony

text: The Unified Communications Interoperability Forum (UCIF), a non-profit alliance between communications vendors, launched in May 2010. The organization's vision is to maximize the interoperability of UC based on existing standards. Founding members of UCIF include HP, Microsoft, Polycom, Logitech/LifeSize Communications, and Juniper Networks.


title: Videotelephony

text: Videoconferencing in the late 20th century was limited to the H.323 protocol (notably Cisco's SCCP implementation was an exception), but newer videophones often use SIP, which is often easier to set up in home networking environments. It is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). H.323 is still used, but more commonly for business videoconferencing, while SIP is more commonly used in personal consumer videophones. A number of call-setup methods based on instant messaging protocols such as Skype also now provide video.


title: Videotelephony

text: Another protocol used by videophones is H.324, which mixes call setup and video compression. Videophones that work on regular phone lines typically use H.324, but the bandwidth is limited by the modem to around 33 kbit/s, limiting the video quality and frame rate. A slightly modified version of H.324 called 3G-324M defined by 3GPP is also used by some cellphones that allow video calls, typically for use only in UMTS networks.


title: Videotelephony

text: There is also H.320 standard, which specified technical requirements for narrow-band visual telephone systems and terminal equipment, typically for videoconferencing and videophone services. It applied mostly to dedicated circuit-based switched network (point-to-point) connections of moderate or high bandwidth, such as through the medium-bandwidth ISDN digital phone protocol or a fractionated high bandwidth T1 lines. Modern products based on H.320 standard usually support also H.323 standard.


title: Videotelephony

text: The IAX2 protocol also supports videophone calls natively, using the protocol's own capabilities to transport alternate media streams. A few hobbyists obtained the Nortel 1535 Color SIP Videophone cheaply in 2010 as surplus after Nortel's bankruptcy and deployed the sets on the Asterisk (PBX) platform. While additional software is required to patch together multiple video feeds for conference calls or convert between dissimilar video standards, SIP calls between two identical handsets within the same PBX were relatively straightforward.


title: Videotelephony

text: The components within a videoconferencing system can be divided up into several different layers: User Interface, Conference Control, Control or Signaling Plane, and Media Plane.


title: Videotelephony

text: Videoconferencing User Interfaces (VUI) can be either graphical or voice-responsive. Many in the industry have encountered both types of interface, and normally a graphical interface is encountered on a computer. User interfaces for conferencing have a number of different uses; they can be used for scheduling, setup, and making a videocall. Through the user interface the administrator is able to control the other three layers of the system.


title: Videotelephony

text: Conference Control performs resource allocation, management, and routing. This layer along with the User Interface creates meetings (scheduled or unscheduled) or adds and removes participants from a conference.


title: Videotelephony

text: Control (Signaling) Plane contains the stacks that signal different endpoints to create a call and/or a conference. Signals can be, but aren't limited to, H.323 and Session Initiation Protocol (SIP) Protocols. These signals control incoming and outgoing connections as well as session parameters.


title: Videotelephony

text: The Media Plane controls the audio and video mixing and streaming. This layer manages Real-Time Transport Protocols, User Datagram Packets (UDP) and Real-Time Transport Control Protocol (RTCP). The RTP and UDP normally carry information such the payload type which is the type of codec, frame rate, video size, and many others. RTCP on the other hand acts as a quality control Protocol for detecting errors during streaming.


title: Videotelephony

text: Simultaneous videoconferencing among three or more remote points is possible in a hardware-based system by means of a Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU, or the MCU can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen on-screen at once. MCUs can be stand-alone hardware devices, or they can be embedded into dedicated videoconferencing units.


title: Videotelephony

text: The MC controls the conferencing while it is active on the signaling plane, which is simply where the system manages conferencing creation, endpoint signaling and in-conferencing controls. This component negotiates parameters with every endpoint in the network and controls conferencing resources.


title: Videotelephony

text: While the MC controls resources and signaling negotiations, the MP operates on the media plane and receives media from each endpoint. The MP generates output streams from each endpoint and redirects the information to other endpoints in the conference.


title: Videotelephony

text: Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H.323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. The advantages of this technique are that the video and audio will generally be of higher quality because they don't have to be relayed through a central point. Also, users can make ad hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.


title: Videotelephony

text: Cloud-based videoconferencing can be used without the hardware generally required by other videoconferencing systems, and can be designed for use by SMEs, or larger international or multinational corporations like Facebook. Cloud-based systems can handle either 2D or 3D video broadcasting. Cloud-based systems can also implement mobile calls, VOIP, and other forms of video calling. They can also come with a video recording function to archive past meetings.


title: Videotelephony

text: High speed Internet connectivity has become more widely available and affordable, as has good-quality video capture and display hardware. Consequently, personal videoconferencing systems based on webcams, personal computer systems, software compression, and the Internet have become progressively more affordable by the general public. The availability of freeware (often as part of chat programs) has made software based videoconferencing accessible to many.


title: Videotelephony

text: The widest deployment of videotelephony now occurs in mobile phones. Nearly all mobile phones supporting UMTS networks can work as videophones using their internal cameras and are able to make video calls wirelessly to other UMTS users anywhere. As of the second quarter of 2007, there are over 131 million UMTS users (and hence potential videophone users), on 134 networks in 59 countries. Mobile phones can also use broadband wireless Internet, whether through the cell phone network or over a local Wi-Fi connection, along with software-based videophone apps to make calls to any video-capable Internet user, whether mobile or fixed.


title: Videotelephony

text: Deaf, hard-of-hearing, and mute individuals have a particular role in the development of affordable high-quality videotelephony as a means of communicating with each other in sign language. Unlike Video Relay Service, which is intended to support communication between a caller using sign language and another party using spoken language, videoconferencing can be used directly between two deaf signers.


title: Videotelephony

text: Videophones are increasingly used in the provision of telemedicine to the elderly, disabled, and to those in remote locations, where the ease and convenience of quickly obtaining diagnostic and consultative medical services are readily apparent. In one single instance quoted in 2006: "A nurse-led clinic at Letham has received positive feedback on a trial of a video-link which allowed 60 pensioners to be assessed by medics without travelling to a doctor's office or medical clinic." A further improvement in telemedical services has been the development of new technology incorporated into special videophones to permit remote diagnostic services, such as blood sugar level, blood pressure, and vital signs monitoring. Such units are capable of relaying both regular audio-video plus medical data over either standard (POTS) telephone or newer broadband lines.


title: Videotelephony

text: Videotelephony has also been deployed in corporate teleconferencing, also available through the use of public access videoconferencing rooms. A higher level of videoconferencing that employs advanced telecommunication technologies and high-resolution displays is called "telepresence".


title: Videotelephony

text: Today the principles, if not the precise mechanisms, of a videophone are employed by many users worldwide in the form of webcam videocalls using personal computers, with inexpensive webcams, microphones, and free videocalling Web client programs. Thus an activity that was disappointing as a separate service has found a niche as a minor feature in software products intended for other purposes.


title: Videotelephony

text: A study conducted by Pew Research in 2010, revealed that 7% of Americans have made a mobile video call.


title: Videotelephony

text: In the United States, videoconferencing has allowed testimony to be used for an individual who is unable or prefers not to attend the physical legal settings or would be subjected to severe psychological stress in doing so, however, there is a controversy on the use of testimony by foreign or unavailable witnesses via video transmission, regarding the violation of the Confrontation Clause of the Sixth Amendment of the U.S. Constitution.


title: Videotelephony

text: In a military investigation in North Carolina, Afghan witnesses have testified via videoconferencing.


title: Videotelephony

text: In Hall County, Georgia, videoconferencing systems are used for initial court appearances. The systems link jails with court rooms, reducing the expenses and security risks of transporting prisoners to the courtroom.


title: Videotelephony

text: The U.S. Social Security Administration (SSA), which oversees the world's largest administrative judicial system under its Office of Disability Adjudication and Review (ODAR), has made extensive use of videoconferencing to conduct hearings at remote locations. In Fiscal Year (FY) 2009, the U.S. Social Security Administration (SSA) conducted 86,320 videoconferenced hearings, a 55% increase over FY 2008. In August 2010, the SSA opened its fifth and largest videoconferencing-only National Hearing Center (NHC), in St. Louis, Missouri. This continues the SSA's effort to use video hearings as a means to clear its substantial hearing backlog. Since 2007, the SSA has also established NHCs in Albuquerque, New Mexico, Baltimore, Maryland, Falls Church, Virginia, and Chicago.


title: Videotelephony

text: Videoconferencing provides students with the chance to learn by participating in two-way communication forums. Because it is live, videotelephony allows teachers to access remote or otherwise isolated learners. Students from diverse communities and backgrounds can come together to learn about one another through practices known as telecollaboration(in foreign language education) and virtual exchange, although language barriers will continue to be present. Such students are able to explore, communicate, analyze, and share information and ideas with one another.


title: Videotelephony

text: Through videoconferencing, students can visit other parts of the world, including museums and other cultural and educational sites. Such virtual field trips can provide enriched learning opportunities to students, especially those who are geographically isolated or economically disadvantaged. Small schools can use these technologies to pool resources and provide courses, such as in foreign languages, which could not otherwise be offered.


title: Videotelephony

text: Videoconferencing is a highly useful technology for real time telemedicine and telenursing applications, such as diagnosis, consulting, prevention, treatment, and transmission of medical images. With videoconferencing, patients may contact nurses and physicians in emergency or routine situations; physicians and other paramedical professionals can discuss cases across large distances. Rural areas can use this technology for diagnostic purposes, thus saving lives and making more efficient use of health care money. For example, a rural medical center in Ohio used videoconferencing to successfully cut the number of transfers of sick infants to a hospital away. This had previously cost nearly $10,000 per transfer.


title: Videotelephony

text: Special peripherals such as microscopes fitted with digital cameras, videoendoscopes, medical ultrasound imaging devices, otoscopes, etc., can be used in conjunction with videoconferencing equipment to transmit data about a patient. Recent developments in mobile collaboration on hand-held mobile devices have also extended video-conferencing capabilities to locations previously unreachable, such as a remote community, long-term care facility, or a patient's home.


title: Videotelephony

text: Videoconferencing can enable individuals in distant locations to participate in meetings on short notice, with time and money savings. Technology such as VoIP can be used in conjunction with desktop videoconferencing to enable low-cost face-to-face business meetings without leaving the desk, especially for businesses with widespread offices. The technology is also used for remote work. One research report based on a sampling of 1,800 corporate employees showed that, as of June 2010, 54% of the respondents with access to videoconferencing used it "all of the time" or "frequently".


title: Videotelephony

text: Intel Corporation have used videoconferencing to reduce both costs and environmental impacts of its business operations.


title: Videotelephony

text: Videoconferencing is also currently being introduced on online networking websites, in order to help businesses form profitable relationships quickly and efficiently without leaving their place of work. This has been leveraged by banks to connect busy banking professionals with customers in various locations using video banking technology.


title: Videotelephony

text: Videoconferencing on hand-held mobile devices (mobile collaboration technology) is being used in industries such as manufacturing, energy, healthcare, insurance, government, and public safety. Live, visual interaction removes traditional restrictions of distance and time, often in locations previously unreachable, such as a manufacturing plant floor thousands of miles away.


title: Videotelephony

text: In the increasingly globalized film industry, videoconferencing has become useful as a method by which creative talent in many different locations can collaborate closely on the complex details of film production. For example, for the 2013 award-winning animated film "Frozen", Burbank-based Walt Disney Animation Studios hired the New York City-based husband-and-wife songwriting team of Robert Lopez and Kristen Anderson-Lopez to write the songs, which required two-hour-long transcontinental videoconferences nearly every weekday for about 14 months.


title: Videotelephony

text: With the development of lower-cost endpoints, the integration of video cameras into personal computers and mobile devices, and software applications such as FaceTime, Skype, Teams and Zoom, videoconferencing has changed from just a business-to-business offering to include business-to-consumer (and consumer-to-consumer) use.


title: Videotelephony

text: Although videoconferencing has frequently proven its value, research has shown that some non-managerial employees prefer not to use it due to several factors, including anxiety. Some such anxieties can often be avoided if managers use the technology as part of the normal course of business. Remote workers can also adopt certain behaviors and best practices to stay connected with their co-workers and company.


title: Videotelephony

text: Researchers also find that attendees of business and medical videoconferences must work harder to interpret information delivered during a conference than they would if they attended face-to-face. They recommend that those coordinating videoconferences make adjustments to their conferencing procedures and equipment.


title: Videotelephony

text: The concept of press videoconferencing was developed in October 2007 by the PanAfrican Press Association (APPA), a Paris France-based non-governmental organization, to allow African journalists to participate in international press conferences on developmental and good governance issues.


title: Videotelephony

text: Press videoconferencing permits international press conferences via videoconferencing over the Internet. Journalists can participate on an international press conference from any location, without leaving their offices or countries. They need only be seated by a computer connected to the Internet in order to ask their questions.


title: Videotelephony

text: In 2004, the International Monetary Fund introduced the Online Media Briefing Center, a password-protected site available only to professional journalists. The site enables the IMF to present press briefings globally and facilitates direct questions to briefers from the press. The site has been copied by other international organizations since its inception. More than 4,000 journalists worldwide are currently registered with the IMF.


title: Videotelephony

text: One of the first demonstrations of the ability for telecommunications to help sign language users communicate with each other occurred when AT&T's videophone (trademarked as the "Picturephone") was introduced to the public at the 1964 New York World's Fair—two deaf users were able to communicate freely with each other between the fair and another city. Various universities and other organizations, including British Telecom's Martlesham facility, have also conducted extensive research on signing via videotelephony.


title: Videotelephony

text: The use of sign language via videotelephony was hampered for many years due to the difficulty of its use over slow analogue copper phone lines, coupled with the high cost of better quality ISDN (data) phone lines. Those factors largely disappeared with the introduction of more efficient and powerful video codecs and the advent of lower cost high-speed ISDN data and IP (Internet) services in the 1990s.


title: Videotelephony

text: Significant improvements in video call quality of service for the deaf occurred in the United States in 2003 when Sorenson Media Inc. (formerly Sorenson Vision Inc.), a video compression software coding company, developed its VP-100 model stand-alone videophone specifically for the deaf community. It was designed to output its video to the user's television in order to lower the cost of acquisition, and to offer remote control and a powerful video compression codec for unequaled video quality and ease of use with video relay services. Favourable reviews quickly led to its popular usage at educational facilities for the deaf, and from there to the greater deaf community.


title: Videotelephony

text: Coupled with similar high-quality videophones introduced by other electronics manufacturers, the availability of high speed Internet, and sponsored video relay services authorized by the U.S. Federal Communications Commission in 2002, VRS services for the deaf underwent rapid growth in that country.


title: Videotelephony

text: Using such video equipment in the present day, the deaf, hard-of-hearing, and speech-impaired can communicate between themselves and with hearing individuals using sign language. The United States and several other countries compensate companies to provide "Video Relay Services" (VRS). Telecommunication equipment can be used to talk to others via a sign language interpreter, who uses a conventional telephone at the same time to communicate with the deaf person's party. Video equipment is also used to do on-site sign language translation via Video Remote Interpreting (VRI). The relatively low cost and widespread availability of 3G mobile phone technology with video calling capabilities have given deaf and speech-impaired users a greater ability to communicate with the same ease as others. Some wireless operators have even started free sign language gateways.


title: Videotelephony

text: Sign language interpretation services via VRS or by VRI are useful in the present day where one of the parties is deaf, hard-of-hearing, or speech-impaired (mute). In such cases the interpretation flow is normally within the same principal language, such as French Sign Language (LSF) to spoken French, Spanish Sign Language (LSE) to spoken Spanish, British Sign Language (BSL) to spoken English, and American Sign Language (ASL) also to spoken English (since BSL and ASL are completely distinct from each other), German Sign Language (DGS) to spoken German, and so on.


title: Videotelephony

text: Multilingual sign language interpreters, who can also translate as well across principal languages (such as a multilingual interpreter interpreting a call from a deaf person using ASL to reserve a hotel room at a hotel in the Dominican Republic whose staff speaks Spanish only, therefore the interpreter has to use ASL, spoken Spanish, and spoken English to facilitate the call for the deaf person), are also available, albeit less frequently. Such activities involve considerable mental processing efforts on the part of the translator, since sign languages are distinct natural languages with their own construction, semantics and syntax, different from the aural version of the same principal language.


title: Videotelephony

text: With video interpreting, sign language interpreters work remotely with live video and audio feeds, so that the interpreter can see the deaf or mute party, and converse with the hearing party, and vice versa. Much like telephone interpreting, video interpreting can be used for situations in which no on-site interpreters are available. However, video interpreting cannot be used for situations in which all parties are speaking via telephone alone. VRS and VRI interpretation requires all parties to have the necessary equipment. Some advanced equipment enables interpreters to control the video camera remotely, in order to zoom in and out or to point the camera toward the party that is signing.


title: Videotelephony

text: The name "videophone" never became as standardized as its earlier counterpart "telephone", resulting in a variety of names and terms being used worldwide, and even within the same region or country. Videophones are also known as "video phones", "videotelephones" (or "video telephones") and often by an early trademarked name "Picturephone", which was the world's first commercial videophone produced in volume. The compound name "videophone" slowly entered into general use after 1950,


title: Videotelephony

text: "Videophone calls" (also: "videocalls", "video chat") as well as "Skype" and "Skyping" in verb form differ from videoconferencing in that they expect to serve individuals, not groups. However that distinction has become increasingly blurred with technology improvements such as increased bandwidth and sophisticated software clients that can allow for multiple parties on a call. In general everyday usage the term "videoconferencing" is now frequently used instead of "videocall" for point-to-point calls between two units. Both videophone calls and videoconferencing are also now commonly referred to as a "video link".


title: Videotelephony

text: "Webcams" are popular, relatively low-cost devices which can provide live video and audio streams via personal computers, and can be used with many software clients for both video calls and videoconferencing.


title: Videotelephony

text: A "videoconference system" is generally higher cost than a videophone and deploys greater capabilities. A "videoconference" (also known as a "videoteleconference") allows two or more locations to communicate via live, simultaneous two-way video and audio transmissions. This is often accomplished by the use of a multipoint control unit (a centralized distribution and call management system) or by a similar non-centralized multipoint capability embedded in each videoconferencing unit. Again, technology improvements have circumvented traditional definitions by allowing multiple party videoconferencing via web-based applications.


title: Videotelephony

text: A "telepresence system" is a high-end videoconferencing system and service usually employed by enterprise-level corporate offices. Telepresence conference rooms use state-of-the art room designs, video cameras, displays, sound-systems and processors, coupled with high-to-very-high capacity bandwidth transmissions.


title: Videotelephony

text: Typical uses of the various technologies described above include calling one-to-one or conferencing one-to-many or many-to-many for personal, business, educational, deaf Video Relay Service and tele-medical, diagnostic and rehabilitative purposes. personal videocalls to inmates incarcerated in penitentiaries, and videoconferencing to resolve airline engineering issues at maintenance facilities, are being created or evolving on an ongoing basis.


title: Videotelephony

text: Other names for "videophone" that have been used in English are: "Viewphone" (the British Telecom equivalent to ), and "visiophone", a common French translation that has also crept into limited English usage, as well as over twenty less common names and expressions. Latin-based translations of "videophone" in other languages include "vidéophone" (French), "Bildtelefon" (German), "videotelefono" (Italian), both "videófono" and "videoteléfono" (Spanish), both "beeldtelefoon" and "videofoon" (Dutch), and "videofonía" (Catalan).


title: Videotelephony

text: A "telepresence robot" (also telerobotics) is a robotically controlled and motorized videoconferencing display to help give a better sense of remote physical presence for communication and collaboration in an office, home, school, etc. when one cannot be there in person. The robotic avatar device can move about and look around at the command of the remote person it represents.


title: Videotelephony

text: In science fiction literature, names commonly associated with videophones include "telephonoscope", "telephote", "viewphone", "vidphone", "vidfone", and "visiphone". The first example was probably the cartoon "Edison's Telephonoscope" by George du Maurier in "Punch" 1878. In «In the year 2889», published 1889, the French author Jules Verne predicts that «"The transmission of speech is an old story; the transmission of images by means of sensitive mirrors connected by wires is a thing but of yesterday."» In many science fiction movies and TV programs that are set in the future, videophones were used as a primary method of communication. One of the first movies where a videophone was used was Fritz Lang's "Metropolis" (1927).


title: Videotelephony

text: Other notable examples of videophones in popular culture include an iconic scene from the 1968 film set on Space Station V. The movie was released shortly before AT&T began its efforts to commercialize its Picturephone Mod II service in several cities and depicts a video call to Earth using an advanced AT&T videophone—which it predicts will cost $1.70 for a two-minute call in 2001 (a fraction of the company's real rates on Earth in 1968). Film director Stanley Kubrick strove for scientific accuracy, relying on interviews with scientists and engineers at Bell Labs in the United States. Dr. Larry Rabiner of Bell Labs, discussing videophone research in the documentary "2001: The Making of a Myth", stated that in the mid-to late-1960s videophones "...captured the imagination of the public and... of Mr. Kubrick and the people who reported to him". In one "2001" movie scene a central character, Dr. Heywood Floyd, calls home to contact his family, a social feature noted in the "Making of a Myth". Floyd talks with and views his daughter from a space station in orbit above the Earth, discussing what type of present he should bring home for her.


title: Videotelephony

text: A portable videophone is also featured prominently in the 2009 science fiction movie "Moon", where the story's protagonist, Sam Bell, also calls home as well to communicate with loved ones. Bell, the lone occupant of a mining station on the far side of the Earth's moon, finally succeeds in making his video call after an extended work period, but becomes traumatized when viewing his daughter.


title: Videotelephony

text: Other earlier examples of videophones in popular culture included a videophone that was featured in the Warner Bros. cartoon, "Plane Daffy", in which the female spy Hatta Mari used a videophone to communicate with Adolf Hitler (1944), as well as a device with the same functionality has been used by the comic strip character "Dick Tracy", who often used his "2-way wrist TV" to communicate with police headquarters. (1964–1977).


title: Videotelephony

text: By the early 2010s videotelephony and videophones had become commonplace and unremarkable in various forms of media, in part due to their real and ubiquitous presence in common electronic devices and laptop computers. Additionally, TV programming increasingly used videophones to interview subjects of interest and to present live coverage by news correspondents, via the Internet or by satellite links. In the mass market media, the popular U.S. TV talk show hostess Oprah Winfrey incorporated videotelephony into her TV program on a regular basis from May 21, 2009, with an initial episode called "Where the Skype Are You?", as part of a marketing agreement with the Internet telecommunication company Skype.


title: Legionnaires' disease

text: Legionnaires' disease is a form of atypical pneumonia caused by any species of "Legionella" bacteria, quite often "Legionella pneumophila". Signs and symptoms include cough, shortness of breath, high fever, muscle pains, and headaches. Nausea, vomiting, and diarrhea may also occur. This often begins 2–10 days after exposure.


title: Legionnaires' disease

text: A legionellosis is any disease caused by "Legionella", including Legionnaires' disease (a pneumonia), Pontiac fever (a nonpneumonia illness), and Pittsburgh pneumonia, but Legionnaires' disease is the most common, so mentions of legionellosis often refer to Legionnaires' disease.


title: Legionnaires' disease

text: The bacterium is found naturally in fresh water. It can contaminate hot water tanks, hot tubs, and cooling towers of large air conditioners. It is usually spread by breathing in mist that contains the bacteria. It can also occur when contaminated water is aspirated. It typically does not spread directly between people, and most people who are exposed do not become infected. Risk factors for infection include older age, a history of smoking, chronic lung disease, and poor immune function. Those with severe pneumonia and those with pneumonia and a recent travel history should be tested for the disease. Diagnosis is by a urinary antigen test and sputum culture.


title: Legionnaires' disease

text: No vaccine is available. Prevention depends on good maintenance of water systems. Treatment of Legionnaires' disease is with antibiotics. Recommended agents include fluoroquinolones, azithromycin, or doxycycline. Hospitalization is often required. The fatality rate is around 10% for healthy persons and 25% for those with underlying conditions.


title: Legionnaires' disease

text: The number of cases that occur globally is not known. Legionnaires' disease is the cause of an estimated 2–9% of pneumonia cases that are acquired outside of a hospital. An estimated 8,000 to 18,000 cases a year in the United States require hospitalization. Outbreaks of disease account for a minority of cases. While it can occur any time of the year, it is more common in the summer and fall. The disease is named after the outbreak where it was first identified, at a 1976 American Legion convention in Philadelphia.


title: Legionnaires' disease

text: The length of time between exposure to the bacteria and the appearance of symptoms (incubation period) is generally 2–10 days, but can more rarely extend to as long as 20 days. For the general population, among those exposed, between 0.1 and 5.0% develop the disease, while among those in hospital, between 0.4 and 14% develop the disease.


title: Legionnaires' disease

text: Those with Legionnaires' disease usually have fever, chills, and a cough, which may be dry or may produce sputum. Almost all experience fever, while around half have cough with sputum, and one-third cough up blood or bloody sputum. Some also have muscle aches, headache, tiredness, loss of appetite, loss of coordination (ataxia), chest pain, or diarrhea and vomiting. Up to half of those with Legionnaires' disease have gastrointestinal symptoms, and almost half have neurological symptoms, including confusion and impaired cognition. "Relative bradycardia" may also be present, which is low to normal heart rate despite the presence of a fever.


title: Legionnaires' disease

text: Laboratory tests may show that kidney functions, liver functions, and electrolyte levels are abnormal, which may include low sodium in the blood. Chest X-rays often show pneumonia with consolidation in the bottom portion of both lungs. Distinguishing Legionnaires' disease from other types of pneumonia by symptoms or radiologic findings alone is difficult; other tests are required for definitive diagnosis.


title: Legionnaires' disease

text: People with Pontiac fever, a much milder illness caused by the same bacterium, experience fever and muscle aches without pneumonia. They generally recover in 2–5 days without treatment. For Pontiac fever, the time between exposure and symptoms is generally a few hours to two days.


title: Legionnaires' disease

text: Over 90% of cases of Legionnaires' disease are caused by "Legionella pneumophila." Other types include "L. longbeachae", "L. feeleii", "L. micdadei", and "L. anisa".


title: Legionnaires' disease

text: Legionnaires' disease is usually spread by the breathing in of aerosolized water or soil contaminated with the "Legionella" bacteria. Experts have stated that Legionnaires' disease is not transmitted from person to person. In 2014, one case of possible spread from someone sick to the caregiver occurred. Rarely, it has been transmitted by direct contact between contaminated water and surgical wounds. The bacteria grow best at warm temperatures and thrive at water temperatures between , with an optimum temperature of . Temperatures above kill the bacteria. Sources where temperatures allow the bacteria to thrive include hot water tanks, cooling towers, and evaporative condensers of large air conditioning systems, such as those commonly found in hotels and large office buildings. Though the first known outbreak was in Philadelphia, cases of legionellosis have occurred throughout the world.


title: Legionnaires' disease

text: "L. pneumophila" thrives in aquatic systems, where it is established within amoebae in a symbiotic relationship. "Legionella" bacteria survive in water as intracellular parasites of water-dwelling protozoa, such as amoebae. Amoebae are often part of biofilms, and once "Legionella" and infected amoebae are protected within a biofilm, they are particularly difficult to destroy.


title: Legionnaires' disease

text: In the built environment, central air conditioning systems in office buildings, hotels, and hospitals are sources of contaminated water. Other places the bacteria can dwell include cooling towers used in industrial cooling systems, evaporative coolers, nebulizers, humidifiers, whirlpool spas, hot water systems, showers, windshield washers, fountains, room-air humidifiers, ice-making machines, and misting systems typically found in grocery-store produce sections.


title: Legionnaires' disease

text: The bacteria may also be transmitted from contaminated aerosols generated in hot tubs if the disinfection and maintenance programs are not followed rigorously. Freshwater ponds, creeks, and ornamental fountains are potential sources of "Legionella". The disease is particularly associated with hotels, fountains, cruise ships, and hospitals with complex potable water systems and cooling systems. Respiratory-care devices such as humidifiers and nebulizers used with contaminated tap water may contain "Legionella" species, so using sterile water is very important. Other sources include exposure to potting mix and compost.


title: Legionnaires' disease

text: "Legionella" spp. enter the lungs either by aspiration of contaminated water or inhalation of aerosolized contaminated water or soil. In the lung, the bacteria are consumed by macrophages, a type of white blood cell, inside of which the "Legionella" bacteria multiply, causing the death of the macrophage. Once the macrophage dies, the bacteria are released from the dead cell to infect other macrophages. Virulent strains of "Legionella" kill macrophages by blocking the fusion of phagosomes with lysosomes inside the host cell; normally, the bacteria are contained inside the phagosome, which merges with a lysosome, allowing enzymes and other chemicals to break down the invading bacteria.


title: Legionnaires' disease

text: People of any age may develop Legionnaires' disease, but the illness most often affects middle-aged and older people, particularly those who smoke cigarettes or have chronic lung disease. Immunocompromised people are also at higher risk. Pontiac fever most commonly occurs in those who are otherwise healthy.


title: Legionnaires' disease

text: The most useful diagnostic tests detect the bacteria in coughed-up mucus, find "Legionella" antigens in urine samples, or allow comparison of "Legionella" antibody levels in two blood samples taken 3–6 weeks apart. A urine antigen test is simple, quick, and very reliable, but only detects "L. pneumophila" serogroup 1, which accounts for 70% of disease caused by "L. pneumophila", which means use of the urine antigen test alone may miss as many as 30% of cases. This test was developed by Richard Kohler in 1982. When dealing with "L. pneumophila" serogroup 1, the urine antigen test is useful for early detection of Legionnaire's disease and initiation of treatment, and has been helpful in early detection of outbreaks. However, it does not identify the specific subtypes, so it cannot be used to match the person with the environmental source of infection. The "Legionella" bacteria can be cultured from sputum or other respiratory samples. "Legionella" spp. stain poorly with Gram stain, stain positive with silver, and are cultured on charcoal yeast extract with iron and cysteine (CYE agar).


title: Legionnaires' disease

text: A significant under-reporting problem occurs with legionellosis. Even in countries with effective health services and readily available diagnostic testing, about 90% of cases of Legionnaires' disease are missed. This is partly due to the disease being a relatively rare form of pneumonia, which many clinicians may not have encountered before, thus may misdiagnose. A further issue is that people with legionellosis can present with a wide range of symptoms, some of which (such as diarrhea) may distract clinicians from making a correct diagnosis.


title: Legionnaires' disease

text: Although the risk of Legionnaires' disease being spread by large-scale water systems cannot be eliminated, it can be greatly reduced by writing and enforcing a highly detailed, systematic water safety plan appropriate for the specific facility involved (office building, hospital, hotel, spa, cruise ship, etc.) Some of the elements that such a plan may include are:


title: Legionnaires' disease

text: An effective water safety plan also covers such matters as training, record-keeping, communication among staff, contingency plans, and management responsibilities. The format and content of the plan may be prescribed by public health laws or regulations. To inform the water safety plan, the undertaking of a site specific legionella risk assessment is often recommended in the first instance. The legionella risk assessment identifies the hazards, the level of risk they pose and provides recommendations of control measures to put place within the overarching water safety plan.


title: Legionnaires' disease

text: Effective antibiotics include most macrolides, tetracyclines, ketolides, and quinolones. "Legionella" spp. multiply within the cell, so any effective treatment must have excellent intracellular penetration. Current treatments of choice are the respiratory tract quinolones (levofloxacin, moxifloxacin, gemifloxacin) or newer macrolides (azithromycin, clarithromycin, roxithromycin). The antibiotics used most frequently have been levofloxacin, doxycycline, and azithromycin.


title: Legionnaires' disease

text: Macrolides (azithromycin) are used in all age groups, while tetracyclines (doxycycline) are prescribed for children above the age of 12 and quinolones (levofloxacin) above the age of 18. Rifampicin can be used in combination with a quinolone or macrolide. Whether rifampicin is an effective antibiotic to take for treatment is uncertain. The Infectious Diseases Society of America does not recommend the use of rifampicin with added regimens. Tetracyclines and erythromycin led to improved outcomes compared to other antibiotics in the original American Legion outbreak. These antibiotics are effective because they have excellent intracellular penetration in "Legionella"-infected cells. The recommended treatment is 5–10 days of levofloxacin or 3–5 days of azithromycin, but in people who are immunocompromised, have severe disease, or other pre-existing health conditions, longer antibiotic use may be necessary. During outbreaks, prophylactic antibiotics have been used to prevent Legionnaires' disease in high-risk individuals who have possibly been exposed.


title: Legionnaires' disease

text: The mortality at the original American Legion convention in 1976 was high (29 deaths in 182 infected individuals) because the antibiotics used (including penicillins, cephalosporins, and aminoglycosides) had poor intracellular penetration. Mortality has plunged to less than 5% if therapy is started quickly. Delay in giving the appropriate antibiotic leads to higher mortality.


title: Legionnaires' disease

text: The fatality rate of Legionnaires' disease has ranged from 5–30% during various outbreaks and approaches 50% for nosocomial infections, especially when treatment with antibiotics is delayed. Hospital-acquired "Legionella" pneumonia has a fatality rate of 28%, and the principal source of infection in such cases is the drinking-water distribution system.


title: Legionnaires' disease

text: Legionnaires' disease acquired its name in July 1976, when an outbreak of pneumonia occurred among people attending a convention of the American Legion at the Bellevue-Stratford Hotel in Philadelphia. Of the 182 reported cases, mostly men, 29 died. On 18 January 1977, the causative agent was identified as a previously unknown strain of bacteria, subsequently named "Legionella", and the species that caused the outbreak was named "Legionella pneumophila". Following this discovery, unexplained outbreaks of severe respiratory disease from the 1950s were retrospectively attributed to "Legionella". Legionnaires' disease also became a prominent historical example of an emerging infectious disease.


title: Legionnaires' disease

text: Outbreaks of Legionnaires' disease receive significant media attention, but this disease usually occurs in single, isolated cases not associated with any recognized outbreak. When outbreaks do occur, they are usually in the summer and early autumn, though cases may occur at any time of year. Most infections occur in those who are middle-aged or older. National surveillance systems and research studies were established early, and in recent years, improved ascertainment and changes in clinical methods of diagnosis have contributed to an upsurge in reported cases in many countries. Environmental studies continue to identify novel sources of infection, leading to regular revisions of guidelines and regulations. About 8,000 to 18,000 cases of Legionnaires' disease occur each year in the United States, according to the Bureau of Communicable Disease Control.


title: Legionnaires' disease

text: Between 1995 and 2005, over 32,000 cases of Legionnaires' disease and more than 600 outbreaks were reported to the European Working Group for Legionella Infections. The data on "Legionella" are limited in developing countries, and "Legionella"-related illnesses likely are underdiagnosed worldwide. Improvements in diagnosis and surveillance in developing countries would be expected to reveal far higher levels of morbidity and mortality than are currently recognised. Similarly, improved diagnosis of human illness related to "Legionella" species and serogroups other than "Legionella pneumophila" would improve knowledge about their incidence and spread.


title: Legionnaires' disease

text: A 2011 study successfully used modeling to predict the likely number of cases during Legionnaires' outbreaks based on symptom onset dates from past outbreaks. In this way, the eventual likely size of an outbreak can be predicted, enabling efficient and effective use of public-health resources in managing an outbreak.


title: Legionnaires' disease

text: During the COVID-19 pandemic, some researchers and organisations raised concerns about the impact of the COVID-19 lockdowns on Legionnaire's disease outbreaks. Additionally, at least two people in England died from a co-infection of "Legionella" and SARS-CoV-2.


title: Legionnaires' disease

text: An outbreak is defined as two or more cases where the onset of illness is closely linked in time (weeks rather than months) and space, where a suspicion or evidence exists of a common source of infection, with or without microbiological support ("i.e." common spatial location of cases from travel history).


title: Legionnaires' disease

text: In April 1985, 175 people in Stafford, England, were admitted to the District or Kingsmead Stafford Hospitals with chest infection or pneumonia. A total of 28 people died. Medical diagnosis showed that Legionnaires' disease was responsible and the immediate epidemiological investigation traced the source of the infection to the air-conditioning cooling tower on the roof of Stafford District Hospital.


title: Legionnaires' disease

text: In March 1999, a large outbreak in the Netherlands occurred during the Westfriese Flora flower exhibition in Bovenkarspel; 318 people became ill and at least 32 people died. This was the second-deadliest outbreak since the 1976 outbreak and possibly the deadliest, as several people were buried before Legionnaires' disease had been diagnosed.


title: Legionnaires' disease

text: The world's largest outbreak of Legionnaires' disease happened in July 2001, with people appearing at the hospital on 7 July, in Murcia, Spain. More than 800 suspected cases were recorded by the time the last case was treated on 22 July; 636–696 of these cases were estimated and 449 confirmed (so, at least 16,000 people were exposed to the bacterium) and six died, a case-fatality rate around 1%.


title: Legionnaires' disease

text: In September 2005, 127 residents of a nursing home in Canada became ill with "L. pneumophila". Within a week, 21 of the residents had died. Culture results at first were negative, which is not unusual, as "L. pneumophila" is a "fastidious" bacterium, meaning it requires specific nutrients, living conditions, or both to grow. The source of the outbreak was traced to the air-conditioning cooling towers on the nursing home's roof.


title: Legionnaires' disease

text: In an outbreak in lower Quebec City, Canada, 180 people were affected with 13 resulting deaths due to contaminated water in a cooling tower.


title: Legionnaires' disease

text: In November 2014, 302 people were hospitalized following an outbreak of legionellosis in Portugal, and seven related deaths were reported. All cases emerged in three civil parishes from the municipality of Vila Franca de Xira in the northern outskirts of Lisbon, and were treated in hospitals of the greater Lisbon area. The source is suspected to be located in the cooling towers of the fertilizer plant Fertibéria.


title: Legionnaires' disease

text: Twelve people were diagnosed with the disease in an outbreak in the Bronx, New York, in December 2014; the source was traced to contaminated cooling towers at a housing development. In July and August 2015, another, unrelated outbreak in the Bronx killed 12 people and made about 120 people sick; the cases arose from a cooling tower on top of a hotel. At the end of September, another person died of the disease and 13 were sickened in yet another unrelated outbreak in the Bronx. The cooling towers from which the people were infected in the latter outbreak had been cleaned during the summer outbreak, raising concerns about how well the bacteria could be controlled.


title: Legionnaires' disease

text: On 28 August 2015, an outbreak of Legionnaire's disease was detected at San Quentin State Prison in Northern California; 81 people were sickened and the cause was sludge that had built up in cooling towers.


title: Legionnaires' disease

text: Between June 2015, and January 2016, 87 cases of Legionnaires' disease were reported by the Michigan Department of Health and Human Services for the city of Flint, Michigan, and surrounding areas. The outbreak may have been linked to the Flint water crisis, in which the city's water source was changed to a cheaper and inadequately treated source. Ten of those cases were fatal.


title: Legionnaires' disease

text: In November 2017, an outbreak was detected at Hospital de São Francisco Xavier, Lisbon, Portugal, with up to 53 people being diagnosed with the disease and five of them dying from it.


title: Legionnaires' disease

text: In Quincy, Illinois, at the Illinois Veterans Home, a 2015 outbreak of the disease killed 12 people and sickened more than 50 others. It was believed to be caused by infected water supply. Three more cases were identified by November 2017.


title: Legionnaires' disease

text: In the autumn of 2017, 22 cases were reported in a Legionnaires' disease outbreak at Disneyland in Anaheim, California. It was believed to have been caused by a cooling tower that releases mist for the comfort of visitors. The contaminated droplets likely spread to the people in and beyond the park.


title: Legionnaires' disease

text: In July 2019, 11 former guests of the Sheraton Atlanta hotel were diagnosed with the disease, with 55 additional probable cases.


title: Legionnaires' disease

text: In September 2019, 141 visitors to the Western North Carolina Mountain State Fair were diagnosed with Legionnaires' disease, with four reported deaths, after a hot tub exhibit is suspected to have developed and spread the bacteria. At least one additional exposure apparently occurred during the Asheville Quilt Show that took place a few weeks after the fair in the same building where the hot tub exhibit was held. The building had been sanitized after the outbreak.


title: Legionnaires' disease

text: In December 2019, the government of Western Australia's Department of Health was notified of four cases of Legionnaires' disease. Those exposed had recently visited near Bali's Ramayana Resort and Spa in central Kuta.


title: Norfolk, Virginia

text: Norfolk ( ) is an independent city in the Commonwealth of Virginia in the United States. Incorporated in 1705, it had a population of 238,005 at the 2020 census, making it the third-most populous city in Virginia after neighboring Virginia Beach and Chesapeake, and the 94th-largest city in the nation.


title: Norfolk, Virginia

text: Norfolk holds a strategic position as the historical, urban, financial, and cultural center of the Hampton Roads region, which has more than 1.8 million inhabitants and is the thirty-third largest Metropolitan Statistical area in the United States. Officially known as "Virginia Beach-Norfolk-Newport News, VA-NC MSA", the Hampton Roads region is sometimes called "Tidewater" and "Coastal Virginia"/"COVA," although these are broader terms that also include Virginia's Eastern Shore and entire coastal plain. Named for the eponymous natural harbor at the mouth of the Chesapeake Bay, Hampton Roads has ten cities, including Norfolk; seven counties in Virginia; and two counties in North Carolina.


title: Norfolk, Virginia

text: Bordered to the west by the Elizabeth River and to the north by the Chesapeake Bay, the city shares land borders with the independent cities of Chesapeake to its south and Virginia Beach to its east. With coastline along multiple bodies of water, Norfolk has many miles of riverfront and bayfront property, including beaches on the Chesapeake Bay.


title: Norfolk, Virginia

text: The coastal zones are important for the economy. The largest naval base in the world, Naval Station Norfolk, is located in Norfolk along with one of NATO's two Strategic Command headquarters. Additionally Norfolk is an important contributor to the Port of Virginia. It is home to Maersk Line, Limited, which manages the world's largest fleet of US-flag vessels. This low-lying coastal infrastructure is very vulnerable to sea level rise, with water levels expected to rise by more than 5.5 feet by the end of the 21st century.


title: Norfolk, Virginia

text: The city has a long history as a strategic military and transportation point, where many railroad lines started. It is linked to its neighbors by an extensive network of interstate highways, bridges, tunnels, and three bridge-tunnel complexes.


title: Norfolk, Virginia

text: In 1619 the Governor of the Virginia Colony, Sir George Yeardley, incorporated four jurisdictions, termed "citties," for the developed portion of the colony. These formed the basis for colonial representative government in the newly minted House of Burgesses. What would become Norfolk was put under the Elizabeth Cittie incorporation.


title: Norfolk, Virginia

text: In 1634 King Charles I reorganized the colony into a system of shires. The former Elizabeth Cittie became Elizabeth City Shire. After persuading 105 people to settle in the colony, Adam Thoroughgood (who had immigrated to Virginia in 1622 from King's Lynn, Norfolk, England) was granted a large land holding, through the head rights system, along the Lynnhaven River in 1636.


title: Norfolk, Virginia

text: When the South Hampton Roads portion of the shire was separated, Thoroughgood suggested the name of his birthplace for the newly formed New Norfolk County. One year later, it was divided into two counties, Upper Norfolk and Lower Norfolk (the latter now incorporated into the City of Norfolk), chiefly on Thoroughgood's recommendation. This area of Virginia became known as the place of entrepreneurs, including men of the Virginia Company of London.


title: Norfolk, Virginia

text: Norfolk developed in the late-seventeenth century as a "Half Moone" fort was constructed and were acquired from local natives of the Powhatan Confederacy in exchange for 10,000 pounds of tobacco. The House of Burgesses established the "Towne of Lower Norfolk County" in 1680. In 1691, a final county subdivision took place when Lower Norfolk County split to form Norfolk County (included in present-day cities of Norfolk, Chesapeake, and parts of Portsmouth) and Princess Anne County (present-day Virginia Beach).


title: Norfolk, Virginia

text: Norfolk was incorporated in 1705. In 1730, a tobacco inspection site was located here. According to the Tobacco Inspection Act, the inspection was ""At Norfolk Town, upon the fort land, in the County of Norfolk; and Kemp's Landing, in Princess Anne, under one inspection."" In 1736 George II granted it a royal charter as a borough. By 1775, Norfolk developed into what contemporary observers argued was the most prosperous city in Virginia. It was an important port for exporting goods to the British Isles and beyond. In part because of its merchants' numerous trading ties with other parts of the British Empire, Norfolk served as a strong base of Loyalist support during the early part of the American Revolution. After fleeing the colonial capital of Williamsburg, the Royal Governor of Virginia, John Murray, 4th Earl of Dunmore, tried to reestablish control of the colony from Norfolk. Dunmore secured small victories at Norfolk but was soon driven into exile by the Virginia militia, commanded by Colonel Woodford. His departure brought an end to more than 168 years of British rule in Virginia.


title: Norfolk, Virginia

text: On New Year's Day, 1776, Lord Dunmore's fleet of three ships shelled the city of Norfolk for more than eight hours. The gunfire, combined with fires started by the British and spread by the Patriots, destroyed more than 800 buildings, constituting nearly two-thirds of the city. The Patriot forces destroyed the remaining buildings for strategic reasons the following month. Only the walls of Saint Paul's Episcopal Church survived the bombardment and subsequent fires. A cannonball from the bombardment (fired by the "Liverpool") remains within the wall of Saint Paul's.


title: Norfolk, Virginia

text: Following recovery from the Revolutionary War's burning, Norfolk and its citizens struggled to rebuild. In 1804, another serious fire along the city's waterfront destroyed some 300 buildings and the city suffered a serious economic setback. In the War of 1812 between America and Great Britain, Norfolk saw action between American militia led by Richard Lawson and the British navy. On July 13, 1813. A British landing party of 8 marines and 16 sailors landed at the beaches of Norfolk to construct a well and gather water. Richard Lawson concealed his company of militia behind a benign looking sandhill. Richard Lawson and his militia sprang their ambush by opening fire from their concealment behind the Sandhills. The British landing party who suffered 3 marines killed surrendered. Richard Lawson who suffered none killed had his militia destroy the British boat, take all provisions, and take the brass cannon. The American militia under Lawson returned back to town with their prisoners. During the 1820s, agrarian communities across the American South suffered a prolonged recession, which caused many families to migrate to other areas. Many moved west into the Piedmont, or further into Kentucky and Tennessee. This migration also followed the exhaustion of soil due to tobacco cultivation in the Tidewater, where it had been the primary commodity crop for generations.


title: Norfolk, Virginia

text: Virginia made some attempts to phase out slavery and manumissions increased in the two decades following the war. Thomas Jefferson Randolph gained passage of an 1832 resolution for gradual abolition in the state. However, by that time the increased demand from the settlement of the lower South states had created a large internal market for slavery. The invention of the cotton gin in the late-eighteenth century had made profitable the cultivation of short-staple cotton in the uplands, which was widely practiced.


title: Norfolk, Virginia

text: The American Colonization Society proposed to "repatriate" free blacks and freed slaves to Africa by establishing the new colony of Liberia and paying for transportation. But most African-Americans wanted to stay in their birthplace of the United States and achieve freedom and rights there. For a period, many emigrants to Liberia from Virginia and North Carolina embarked from the port of Norfolk. Joseph Jenkins Roberts, a free person of color native to Norfolk, emigrated via the American Colonization Society and later was elected as the first president of Liberia, establishing a powerful family.


title: Norfolk, Virginia

text: On June 7, 1855, the 183-foot vessel "Benjamin Franklin" put into Hampton Roads for repairs. The ship had just sailed from the West Indies, where there had been an outbreak of yellow fever. The port health officer ordered the ship quarantined. After eleven days, a second inspection found no issues, so it was allowed to dock. A few days later, the first cases of yellow fever were discovered in Norfolk, and a machinist died from the disease on July 8. By August, several people were dying per day, and a third of the city's population had fled in the hopes of escaping the epidemic. No one understood how the disease was transmitted. With both Norfolk and Portsmouth being infected, New York banned all traffic from those sites. Neighboring cities also banned residents from Norfolk. The epidemic spread through the city via mosquitoes and poor sanitation, affecting every family and causing widespread panic. The number of infected reached 5,000 in September, and by the second week, 1,500 had died in Norfolk and Portsmouth. As the weather cooled, the outbreak began to wane, leaving a final tally of about 3,200 dead. It took the city some time to recover.


title: Norfolk, Virginia

text: In early 1861, Norfolk voters instructed their delegate to vote for secession. Virginia voted to secede from the Union. In the spring of 1862, the Battle of Hampton Roads took place off the northwest shore of the city's Sewell's Point Peninsula, marking the first fight between two ironclads, the USS "Monitor" and the CSS "Virginia". The battle ended in a stalemate, but changed the course of naval warfare; from then on, warships were fortified with metal.


title: Norfolk, Virginia

text: In May 1862, Norfolk Mayor William Lamb surrendered the city to Union General John E. Wool and his forces. They held the city under martial law for the duration of the Civil War. Thousands of slaves from the region escaped to Union lines to gain freedom; they quickly set up schools in Norfolk to start learning how to read and write, years before the end of the war.


title: Norfolk, Virginia

text: 1907 brought both the Virginian Railway and the Jamestown Exposition to Sewell's Point. The large Naval Review at the Exposition demonstrated the peninsula's favorable location and laid the groundwork for the world's largest naval base. Southern Democrats in Congress gained its location here. Commemorating the tricentennial anniversary of the founding of Jamestown, the exposition featured many prominent officials, including President Theodore Roosevelt, members of Congress, and diplomats from twenty-one countries. By 1917, as the US prepared to enter World War I, the Naval Air Station Hampton Roads had been constructed on the former exposition grounds.


title: Norfolk, Virginia

text: In the first half of the twentieth century, the city of Norfolk expanded its borders through annexation. In 1906, the city annexed the incorporated town of Berkley, making the city cross the Elizabeth River. In 1923, the city expanded to include Sewell's Point, Willoughby Spit, the town of Campostella, and the Ocean View area. The city included the Navy Base and miles of beach property fronting on Hampton Roads and the Chesapeake Bay. After a smaller annexation in 1959, and a 1988 land swap with Virginia Beach, the city assumed its current boundaries.


title: Norfolk, Virginia

text: With the dawn of the Interstate Highway System following World War II, new highways were constructed in the region. A series of bridges and tunnels, constructed during fifteen years, linked Norfolk with the Peninsula, Portsmouth, and Virginia Beach. In 1952, the Downtown Tunnel opened to connect Norfolk with the city of Portsmouth. The highways also stimulated the development of new housing suburbs, leading to the population spreading out. Additional bridges and tunnels included the Hampton Roads Bridge-Tunnel in 1957, the Midtown Tunnel in 1962, and the Virginia Beach-Norfolk Expressway (Interstate 264 and State Route 44) in 1967. In 1991, the new Downtown Tunnel/Berkley Bridge complex opened a new system of multiple lanes of highway and interchanges connecting Downtown Norfolk and Interstate 464 with the Downtown Tunnel tubes.


title: Norfolk, Virginia

text: In 1954 the Supreme Court ruled in "Brown v. Board of Education" that segregated public schools were unconstitutional, as the public system was supported by all taxpayers. It ordered integration, but Virginia pursued a policy of "massive resistance". (At this time, most black citizens were still disfranchised under the state's turn-of-the-century constitution and discriminatory practices related to voter registration and elections.) The Virginia General Assembly prohibited state funding for integrated public schools.


title: Norfolk, Virginia

text: In 1958, United States district courts in Virginia ordered schools to open for the first time on a racially integrated basis. In response, Governor J. Lindsay Almond ordered the schools closed. The Virginia Supreme Court of Appeals declared the state law to be in conflict with the state constitution and ordered all public schools to be funded, whether integrated or not. About ten days later, Almond capitulated and asked the General Assembly to rescind several "massive resistance" laws. In September 1959, seventeen black children entered six previously segregated Norfolk public schools. "Virginian-Pilot" editor Lenoir Chambers editorialized against massive resistance and earned the Pulitzer Prize for Editorial Writing.


title: Norfolk, Virginia

text: With new suburban developments beckoning, many white middle-class residents moved out of the city along new highway routes, and Norfolk's population declined, a pattern repeated in numerous cities during the postwar era independently of segregation issues. In the late-1960s and early-1970s, the advent of newer suburban shopping destinations along with freeways spelled demise for the fortunes of downtown's Granby Street commercial corridor, located just a few blocks inland from the waterfront. The opening of malls and large shopping centers drew off retail business from Granby Street.


title: Norfolk, Virginia

text: Norfolk's city leaders began a long push to revive its urban core. While Granby Street underwent decline, Norfolk city leaders focused on the waterfront and its collection of decaying piers and warehouses. Many obsolete shipping and warehousing facilities were demolished. In their place, planners created a new boulevard, Waterside Drive, along which many of the high-rise buildings in Norfolk's skyline have been erected. In 1983, the city and The Rouse Company developed the Waterside festival marketplace to attract people back to the waterfront and catalyze further downtown redevelopment. Waterside was redeveloped in 2017. Additionally the waterfront area hosts the Nauticus maritime museum and the USS Wisconsin. Other facilities opened in the ensuing years, including the Harbor Park baseball stadium, home of the Norfolk Tides Triple-A minor league baseball team. In 1995, the park was named the finest facility in minor league baseball by "Baseball America". Norfolk's efforts to revitalize its downtown have attracted acclaim from economic development and urban planning circles throughout the country. Downtown's rising fortunes helped to expand the city's revenues and allowed the city to direct attention to other neighborhoods.


title: Norfolk, Virginia

text: The city is located at the southeastern corner of Virginia at the junction of the Elizabeth River and the Chesapeake Bay. The Hampton Roads Metropolitan Statistical Area (officially known as the Virginia Beach-Norfolk-Newport News, VA-NC MSA) is the 37th largest in the United States, with an estimated population of 1,716,624 in 2014. The area includes the Virginia cities of Norfolk, Virginia Beach, Chesapeake, Hampton, Newport News, Poquoson, Portsmouth, Suffolk, Williamsburg, and the counties of Gloucester, Isle of Wight, James City, Mathews, and York, as well as the North Carolina counties of Currituck and Gates. The city of Norfolk is recognized as the central business district, while the Virginia Beach oceanside resort district and Williamsburg are primarily centers of tourism. Virginia Beach is the most populated city within the MSA though it functions more as a suburb. Additionally, Norfolk is part of the Virginia Beach-Norfolk, VA-NC Combined Statistical Area, which includes the Virginia Beach-Norfolk-Newport News, VA-NC MSA, the Elizabeth City, North Carolina Micropolitan Statistical Area, and the Kill Devil Hills, NC Micropolitan Statistical Area. The CSA is the 32nd largest in the nation with an estimated population in 2013 of 1,810,266.


title: Norfolk, Virginia

text: In addition to extensive riverfront property, Norfolk has miles of bayfront resort property and beaches in the Willoughby Spit and Ocean View communities.


title: Norfolk, Virginia

text: Being low-lying and largely surrounded by water, Norfolk is particularly vulnerable to rising sea levels caused by climate change. In addition, the land on which it is built is slowly subsiding. Some areas already flood regularly at high tide, and the city commissioned a study in 2012 to investigate how to address the issue in the future: it reported the cost of dealing with a sea-level rise of one foot would be around $1,000,000,000. Since then, scientists at the Virginia Institute of Marine Science in 2013 have estimated that if current trends hold, the sea in Norfolk will rise by 5 and 1/2 feet or more by the end of this century.


title: Norfolk, Virginia

text: When Norfolk was first settled, homes were made of wood and frame construction, similar to most medieval English-style homes. These homes had wide chimneys and thatch roofs. Some decades after the town was first laid out in 1682, the Georgian architectural style, which was popular in the South at the time, was used. Brick was considered more substantial construction; patterns were made by brick laid and Flemish bond. This style evolved to include projecting center pavilions, Palladian windows, balustraded roof decks, and two-story porticoes. By 1740, homes, warehouses, stores, workshops, and taverns began to dot Norfolk's streets.


title: Norfolk, Virginia

text: Norfolk was burned down during the Revolutionary War. After the Revolution, Norfolk was rebuilt in the Federal style, based on Roman ideals. Federal-style homes kept Georgian symmetry, though they had more refined decorations to look like New World homes. Federal homes had features such as narrow sidelights with an embracing fanlight around the doorway, giant porticoes, gable or flat roofs, and projecting bays on exterior walls. Rooms were oval, elliptical or octagonal. Few of these federal rowhouses remain standing today. A majority of buildings were made of wood and had a simple construction.


title: Norfolk, Virginia

text: In the early nineteenth century, Neoclassical architectural elements began to appear in the federal style row homes, such as ionic columns in the porticoes and classic motifs over doorways and windows. Many Federal-style row houses were modernized by placing a Greek-style porch at the front. Greek and Roman elements were integrated into public buildings such as the old City Hall, the old Norfolk Academy, and the Customs House.


title: Norfolk, Virginia

text: Greek-style homes gave way to Gothic Revival in the 1830s, which emphasized pointed arches, steep gable roofs, towers and tracer-lead windows. The Freemason Baptist Church and St. Mary's Catholic Church are examples of Gothic Revival. Italianate elements emerged in the 1840s including cupolas, verandas, ornamental brickwork, or corner quoins. Norfolk still had simple wooden structures among its more ornate buildings.


title: Norfolk, Virginia

text: High-rise buildings were first built in the late nineteenth century when structures such as the current Commodore Maury Hotel and the Royster Building were constructed to form the initial Norfolk skyline. Past styles were revived during the early years of the twentieth century. Bungalows and apartment buildings became popular for those living in the city.


title: Norfolk, Virginia

text: As the Great Depression wore on, Art Deco emerged as a popular building style, as evidenced by the Post Office building downtown. Art Deco consisted of streamlined concrete faced appearance with smooth stone or metal, with terracotta, and trimming consisting of glass and colored tiles.


title: Norfolk, Virginia

text: Norfolk has a variety of historic neighborhoods. Some neighborhoods, such as Berkley, were formerly cities and towns. Others, such as Willoughby Spit and Ocean View, have a long history tied to the Chesapeake Bay. Today, neighborhoods such as Downtown, Ghent and Fairmount Park have transformed with the revitalization that the city has undergone.


title: Norfolk, Virginia

text: Narrative below is based on climate data from the 1991-2020 period. Norfolk has a humid subtropical climate and its USDA Hardiness Zone is 8a. Spring arrives in March with mild days and cool nights, and by late May, the temperature has warmed up considerably to herald warm summer days. Summers are consistently warm and humid, but the nearby Atlantic Ocean often exercises a slight cooling effect on daytime high temperatures, but a slight warming effect on nighttime low temperatures (compared to areas farther inland). As such, temperatures reach or higher on an average 35 days annually, and are uncommon, occurring in fewer than one-third of all years. On average, July is the warmest month, with a normal mean temperature of . On average, July and August are the wettest months, due to frequent summer thunderstorm activity. In August and September, rainfall remains high, due to rising frequency of tropical activity (hurricanes and tropical storms), which can bring high winds and heavy rains. These usually brush Norfolk and only occasionally make landfalls in the area; the highest-risk period is mid-August to the end of September. Fall is marked by mild to warm days and cooler nights. Winter is usually mild in Norfolk, with average winter days featuring lows near or slightly above freezing and highs in the upper-40s to mid-50s (8 to 13 °C). On average, the coldest month of the year is January, with a normal mean temperature of , Snow occurs sporadically, with an average winter accumulation of . Norfolk's record high was on August 7, 1918, and July 24 and 25, 2010, and the record low was recorded on January 21, 1985.


title: Norfolk, Virginia

text: "Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race."


title: Norfolk, Virginia

text: As of the census of 2010, there were 242,803 people, 86,210 households, and 51,898 families residing in the city. The population density was 4,362.8 people per square mile (1,684.4/km). There were 94,416 housing units at an average density of 1,757.3 per square mile (678.5/km). The racial makeup of the city was 47.1% White, 43.1% African American, 0.5% Native American, 3.3% Asian, 0.2% Pacific Islander, 2.2% from other races, and 3.6% from two or more races. Hispanics or Latinos of any race were 6.6% of the population. Non-Hispanic Whites were 44.3% of the population in 2010, down from 68.5% in 1970.


title: Norfolk, Virginia

text: There were 86,210 households, out of which 30.3% had children under the age of 18 living with them, 36.9% were married couples living together, 18.8% had a female householder with no husband present, and 39.8% were non-families. 30.2% of all households were made up of individuals, and 9.6% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 3.07.


title: Norfolk, Virginia

text: The age distribution was 24.0% under the age of 18, 18.2% from 18 to 24, 29.9% from 25 to 44, 16.9% from 45 to 64, and 10.9% who were 65 years of age or older. The median age was 30 years. For every 100 females, there were 104.6 males. For every 100 females age 18 and over, there were 104.8 males. This large gender imbalance is due to the military presence in the city, most notably Naval Station Norfolk.


title: Norfolk, Virginia

text: The median income for a household in the city was $31,815, and the median income for a family was $36,891. Males had a median income of $25,848 versus $21,907 for females. The per capita income for the city was $17,372. About 15.5% of families and 19.4% of the population were below the poverty line, including 27.9% of those under age 18 and 13.2% of those ages 65 or over.


title: Norfolk, Virginia

text: For the year of 2007, Norfolk had a total crime index of 514.7 per 100,000 residents. This was above the national average of 320.9 that year. For 2007, the city experienced 48 homicides, for a murder rate of 21.1 per 100,000 residents. Total crime had decreased when compared to the year 2000, which the city had a total crime index of 546.3. The highest murder rate Norfolk has experienced for the 21st century was in 2005 when its rate was 24.5 per 100,000 residents. For the year 2007 per 100,000, Norfolk experienced 21.1 murders, 42.6 rapes, 399.3 robberies, 381.3 assaults, 743.3 burglaries, and 450.6 automobile thefts. According to the Congressional Quarterly Press '2008 City Crime Rankings: Crime in Metropolitan America, Norfolk, Virginia, ranked as the 87th most dangerous city larger than 75,000 inhabitants.


title: Norfolk, Virginia

text: Since Norfolk serves as the commercial and cultural center for the unusual geographical region of Hampton Roads (and in its political structure of independent cities), it can be difficult to separate the economic characteristics of Norfolk from that of the region as a whole.


title: Norfolk, Virginia

text: The waterways which almost completely surround the Hampton Roads region play an important part in the local economy. As a strategic location at the mouth of the Chesapeake Bay, its protected deep-water channels serve as a major trade artery for the import and export of goods from across the Mid-Atlantic, Mid-West, and internationally.