COVID-19 UPDATES|CORONAVIRUS UPDATES IN INDIA|RELIEF FOR GUJARAT CORONA PATIENTS|INDIA UPDATES 2020
Channel: KNOWLEDGE INFO
Date: 18/04/2020

Coronaviruses vary significantly in risk factor. Some can kill more than 30% of those infected, such as MERS-CoV, and some are relatively harmless, such as the common cold.[24] Coronaviruses can cause colds with major symptoms, such as fever, and a sore throat from swollen adenoids.[55] Coronaviruses can cause pneumonia (either direct viral pneumonia or secondary bacterial pneumonia) and bronchitis (either direct viral bronchitis or secondary bacterial bronchitis).[56] The human coronavirus discovered in 2003, SARS-CoV, which causes severe acute respiratory syndrome (SARS), has a unique pathogenesis because it causes both upper and lower respiratory tract infections.[56]

Six species of human coronaviruses are known, with one species subdivided into two different strains, making seven strains of human coronaviruses altogether. Four of these coronaviruses continually circulate in the human population and produce the generally mild symptoms of the common cold in adults and children worldwide: -OC43, -HKU1, HCoV-229E, -NL63.[57] Coronaviruses cause about 15% of commons colds.[58] The majority of colds are caused by rhinoviruses.[59] The four mild coronaviruses have a seasonal incidence occurring in the winter months in temperate climates.[60][61] There is no preference towards a particular season in tropical climates.[62]

Coronaviruses were first discovered in the 1930s when an acute respiratory infection of domesticated chickens was shown to be caused by infectious bronchitis virus (IBV).[9] Arthur Schalk and MC Hawn described in 1931 a new respiratory infection of chickens in North Dakota. The infection of new-born chicks was characterized by gasping and listlessness. The mortality rate of the chicks was 40–90%.[10] In 1937, Fred Beaudette and Charles Hudson reported that they had successfully isolated and cultivated the infectious bronchitis virus which caused the disease.[11] In the 1940s, two more animal coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), were isolated.[12] It was not realized at the time that these three different viruses were related.[13]

Human coronaviruses were discovered in the 1960s.[14] The earliest ones studied were from human patients with the common cold, which were later named human coronavirus 229E and human coronavirus OC43.[15] They were first imaged by Scottish virologist June Almeida at St. Thomas Hospital in London.[16] Other human coronaviruses have since been identified, including SARS-CoV in 2003, HCoV NL63 in 2004, HKU1 in 2005, MERS-CoV in 2012, and SARS-CoV-2 in 2019. Most of these have involved serious respiratory tract infections.
Seasonal distribution of HCoV-NL63 in Germany shows a preferential detection from November to March
Four human coronaviruses produce symptoms that are generally mild:

Human coronavirus OC43 (HCoV-OC43), β-CoV
Human coronavirus HKU1 (HCoV-HKU1), β-CoV
Human coronavirus 229E (HCoV-229E), α-CoV
Human coronavirus NL63 (HCoV-NL63), α-CoV
Three human coronaviruses produce symptoms that are potentially severe:

Middle East respiratory syndrome-related coronavirus (MERS-CoV), β-CoV
Severe acute respiratory syndrome coronavirus (SARS-CoV), β-CoV
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), β-CoV
Outbreaks of human coronavirus diseases
Severe acute respiratory syndrome (SARS)
Main article: Severe acute respiratory syndrome
Characteristics of human coronavirus strains
MERS-CoV, SARS-CoV, SARS-CoV-2,
and related diseases
MERS-CoV SARS-CoV SARS-CoV-2
Disease MERS SARS COVID-19
Outbreaks 2012, 2015,
2018 2002–2004 2019–2020
pandemic
Epidemiology
Date of first
identified case June
2012 November
2002 December
2019[63]
Location of first
identified case Jeddah,
Saudi Arabia Shunde,
China Wuhan,
China
Age average 56 44[64][a] 56[65]
Sex ratio (M:F) 3.3:1 0.8:1[66] 1.6:1[65]
Confirmed cases 2494 8096[67] 2,256,844[68][b]
Deaths 858 774[67] 154,350[68][b]
Case fatality rate 37% 9.2% 6.8%[68]
Symptoms
Fever 98% 99–100% 87.9%[69]
Dry cough 47% 29–75% 67.7%[69]
Dyspnea 72% 40–42% 18.6%[69]
Diarrhea 26% 20–25% 3.7%[69]
Sore throat 21% 13–25% 13.9%[69]
Ventilatory use 24.5%[70] 14–20% 4.1%[71]
Notes
 Based on data from Hong Kong.
 Data as of 18 April 2020.
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In 2003, following the outbreak of severe acute respiratory syndrome (SARS) which had begun the prior year in Asia, and secondary cases elsewhere in the world, the World Health Organization (WHO) issued a press release stating that a novel coronavirus identified by a number of laboratories was the causative agent for SARS. The virus was officially named the SARS coronavirus (SARS-CoV). More than 8,000 people were infected, about ten percent of whom died