What organism is considered the most common of all serious fungal diseases? Candida albicans Although Candida is a normal endogenous inhabitant of the alimentary tract and the mucocutaneous regions of the body, what is true about its capability of becoming an opportunistic pathogen? It can become an opportunistic pathogen in debilitated and immunocompromised hosts Cellular defenses protect against type of infection? Mucocutaneous infections Most individuals also have some antibodies to organism? C. albicans methods for antibodies give comparable results, and both reliably detect antibodies in systemic candidiasis in immunocompetent hosts? ID and CIE methods What is considered a positive reaction between the reagent antigen and patient’s Formation of one or more bands When is systemic candidiasis presumptively identified? When serial dilutions of specimens show an increasing number of precipitin bands or convert from negative to positive Which test for antibodies is quantitative and can be of diagnostic and prognostic value? The LA test particles sensitized with a homogenate antigen of C. albicans are reacted with what? Patient sera and control sera What is done when LA test for antibodies screening test is positive? A serial dilution is performed and reported as the highest dilution giving a 2+ reaction What suggests an early infection, colonization, or a nonspecific reaction? 1:4 A titer of 1:8 or greater, conversion from a negative to a positive test, or a fourfold increase in titer suggests what? Is presumptive evidence of invasive infection A fourfold decrease in titer may indicate what? Successful therapy What tests must be performed for immunocompromised patients? Tests for antigenemia Why do immunocompromised patients need to have tests for antigenemia? Because antibody-detection tests have little or no value in immunocompromised patients. What antigen tests for candidiasis include? EIA and reverse passive agglutination test What is the etiologic of coccidioidomycosis? Coccidioides immitis
What form of EIA tests are avaialbe to detect antigens of C. neoformans? and CSF eia testing What is the difference between the EIA method and latex agglutination procedure? The EIA method is more sensitive but takes more time to perform. What can be used as both a qualitative screening test and a semiquantitative test to detect and titer antibodies to C. neoformans? Tube agglutination (TA) test For testing what are the Heat-inactivated or CSF from patients with suspected C. neoformans, along with positive and negative controls, mixed with? Cryptococcus antigen suspension of weakly encapsulated yeast cells What takes place to the tubes before it gets read for agglutination? Incubation and refrigeration overnight What titer suggests a current or recent infection with C. neoformans? 1:2 or greater What other tests are available for the detection of antibodies to C. neoformans? Indirect immunofluorescence (IFA) tests, PCR What does a positive Indirect immunofluorescence test suggests? a recent or current infection with C. neoformans or a cross-reaction with another fungus. What testing is not commonly performed for fungi? Molecular testing? What can impair the development of cost-effective screening methods for fungal infections? large number of pathogens that exist What are Spirochetes? long, slender, helically coiled bacteria containing axial filaments, or periplasmic flagella, which wind around the bacterial cell wall and are enclosed by an outer sheath. What kind of motility does organisms exhibit? characteristic corkscrew flexion or motility. What similarities do diseases caused by these organisms include? a localized skin infection that disseminates to numerous organs as the disease progresses, a latent stage, and cardiac and neurological involvement if the disease remains untreated. What are two major spirochete diseases? Syphilis and Lyme disease What is the most commonly acquired spirochete disease in the United States today? Syphilis How is Syphilis typically transmitted? Through sexual transmission How much is the incidence of in 2000? 2.2 cases per 100,000
What occurs once contact has been made with a susceptible skin site? Endothelial cell thickening occurs with aggregation of lymphocytes, plasma and macro phages. What is the initial lesion called? chancre When does a chancre develop? Develops between 10 and 90 days after infection, with three weeks being the average. What is a chancre? A painless, solitary lesion characterized by raised and well-defined borders. Where does chancre usually occur in men? They appear usually on the outside of the penis. does chancre usually occur in women? They may appear in the Regina or on the cervix and thus may go undetected. How long does the primary stage last? One to six weeks. How many percent does the initial chancre, if is untreated, progresses to the secondary stage? 25% How long is the stage observed after the primary chancre disappears? 1 to 2 months. How long can it take for a chancre to heal itself? 3-6 Chancre can occur in which parts of the body? Genitals, mouth, skin, rectum What happens to the nearby lymph nodes near the chancre? They are enlarged What are symptoms of the secondary stage? generalized lymphadenopathy, or enlargement of the lymph nodes; malaise; fever; pharyngitis; and a rash on the skin and mucous membranes. Where can rash symptoms appear? The rash may appear on the palms of the hands and soles of the feet, which is very unusual in other diseases. What can happen to 40% of patients with secondary syphilis? They may exhibit neurological signs such as visual disturbances, hearing loss, tinnitus, and facial weakness. How long can lesions persist? Lesions persist from a few days up to eight weeks. What is the difference between early latent and late latent? Early latent is defined as less than one year duration, late latent is when primary infection has occurred more than one year previously. What stage follows the disappearance of secondary syphilis Latent stage The patients who are infectious during latent stage are who? Pregnant women how many individuals who remain untreated will develop tertiary syphilis? 1/3 of individuals When can tertiary syphilis develop? Between 10 and 30 years following the secondary stage. What are three major manifestations of Tertiary syphilis? Gummas, cardiovascular disease, neurosyphilis
be prevented in non-immunized individuals who have been exposed to the virus by intramuscular injection of immune globulin, a sterile preparation of pooled human plasma that contains antibodies to HAV, or by prophylactic administration of the hepatitis A vaccination. What hepatitis is a non-envelope, RNA virus that belongs to the genus of Hepevirus, in the family Hepiveridae and is transmitted by the fecal-oral route. hepatitis E (HEV) True or False: Most HEV infections are related to consumption of fecally contaminated drinking water in developing regions of Africa, the Middle East, South East Asia, and Central Asia, all of which have poor sanitation conditions. Infections in the United States and other industrialized countries are rare but have been reported. True Following an incubation period of 3 to 8 what hepatitis causes an acute, hepatitis that lasts 1 to 4 weeks in most people who become infected? hepatitis E (HEV) HEV is a fulminant hepatitis, associated with rapidly progressing disease and a high mortality rate, occurs more commonly in _____ women due to their changes in the immune response. pregnant In HEV, does the infection progress to a chronic carrier no Is there a treatment for HEV? no Because HEV is not easily cultured, diagnosis of it relies on what? serology Is acute or chronice infections indicated by the presence of IgM anti-HEV, which is detectable at clinical onset but declines rapidly in the early recovery? True or False: These antibodies are typically identified by highly sensitive enzyme immunoassays that use recombinant and synthetic HEV antigens. True
number of _____ infections continue to occur. Infection with HBV results in an average incubation period of how many days, followed by a clinical course that varies in different age groups? 45 to 90 True or False: Over 90% of newborns with perinatal HBV infection remain asymptomatic, while typical symptoms of acute hepatitis are observed in 15% of children aged 1 to 5 years and in 50% of older children, adolescents, and adults. Symptoms may last several weeks to several months. True Most HBV-infected adults recover within _____ months and develop immunity to the virus, but about 1% develop fulminant liver disease with hepatic necrosis, which has a high rate of fatality. 6 Development of _____ HBV infection, in which the virus persists in the body for six months or more, is independently related to age: chronic hepatitis B develops in about 10% of infected adults, 40% of young children, and 90% of infected infants. chronic Is chronic HBV infection more likely to develop in people who are immunosuppressed or have HIV? yes _____ infection with HBV results in inflammation and damage to the liver, and places the patient at increased risk of developing cirrhosis (seen in 20% of patients with chronic infection) or liver cancer (100 times the risk of non-HBV carriers). chronic What hepatitis virus is a DNA virus of the Hepadnaviridae family? hepatitis B virus (HBV) How many genotypes have been identified for Hepatitis B? 8 Genotype _____ is the predominant one in the U.S and throughout the world. Cafe What is surrounded by an outer envelope of lipoprotein? Intact Virion
The core of the virus contains single stranded RNA or double stranded DNA? Double stranded DNA A protein called the ________________ is found in the outer envelope of the virus. Hepatitis B surface antigen How many proteins are the hepatitis B core antigen and the hepatitis Be antigen? Two Serve as serological markers for hepatitis B and have been used in differential diagnosis of _______, and monitoring the course of infection in patients, in assessing immunity to the virus, and in screening blood products for infectivity. HBV infection The hepatitis B surface antigen is detectable ______ weeks after exposure to HBV 2-10 weeks Its levels peaked during the ______ stages of infection, then gradually decline as the patient develops antibodies to the antigen and recovers. Acute What usually becomes undetectable by six months after onset of symptoms in patients with acute hepatitis B? Serum HBsAg If a patients HBsAg remains elevated for six months or more, what does it mean? Indicator of active infection and important marker in detecting initial infection, monitoring the course of infection and progression to chronic disease and screening of blood donor. The hepatitis Be antigen appears shortly ______ HBsAG and disappears shortly ______ HBsAg and recovering patients. After, before Why is HBC AG not detectable in serum? Viral envelope masks it As the ______ develops an immune response to the virus, antibodies appear. host What is first to appear to the core antigen? IgM antibody The antibody indicates __________ Current or recurrent acute infection. As the host develops an immune reponse to the virus ____________ appear. antibodies It typically occurs __________ after HBsAg during acute infection and persists in high titers for six months and then gradually declines. 1-2 weeks
What types of antibodies help indicate current or recent infection by the presence of mumps? The two types of antibodies are mumps specific IgM antibody in a single serum sample or by at least a fourfold rise in specific IgG antibody between two specimens collected during the acute and convalescent phases of the illness. Why is between antibodies to mump and related paramyxoviruses that have been reported to tests for IgG not an issue? It is not an issue because of differentiation in clinical symptoms. Which antibodies can be detected within four days of illness and can persist for at least 12 weeks? IgM antibodies Which antibodies become detectable within 10 days and persist for years? IgG antibodies The presence of which antibody indicates immunity to mumps, either as a result of natural infection or immunization? IgG antibodies In the United States, most serum allergy tests for mumps are performed to evaluate immune status in which groups of people? Healthcare workers or recipients of the mumps vaccine. What two types of human T cell lymphotropic viruses are closely related? Type I and type II What do these viruses have as their nucleic acid? RNA What enzyme to these viruses contain whose function is to transcribe the viral RNA into DNA? Reverse transcriptase The DNA then becomes integrated into the host cell’s genome as what kind of Provirus What can remain in a latent state within infected cells for a prolonged period of time? Provirus Upon activation of the host cell, the provirus can proceed to complete its replication cycle to produce what? Virions Both HTLV-I and HTLV-II infect T lymphocytes. Which type of T lymphocyte is especially affected, that causes T cell proliferation and have the potential to establish persistent infection? CD4 What can HTLV-II also infect? Macrophages What are the three structural genes called that both HTLV viruses contain? gag, pol, and env
True or False: Altered production of cytokines and chemokines is not seen in HIV False. What other immunologic abnormalities are seen in AIDS patients? List 3. defective antigen presentation, oxidative by monocytes/macrophages and decreased natural killer (NK) cell activity Although the manifestations of the disease vary in individual patients, what is the general clinical course of the disease? It begins with primary, or acute, infection, followed by a period of clinical latency and eventually culminating in AIDS. In the first stage of HIV, high levels of circulating virus, or viremia, exist, and HIV begins to disseminate to what organs? lymphoid organs. As the immune system becomes activated, what syndrome may develop? retroviral syndrome What are symptoms of Acute retroviral syndrome? Symptoms that resemble influenza or infectious mononucleosis. As HIV-specific immune responses develop, they begin to curtail replication of the virus, this period is called? Clinical latency What is the median length of clinical latency in HIV? 10 years If left untreated, what is the final stage of the HIV infection? AIDS How would you characterized AIDS? Profound immunosuppression, a resurgence of viremia, and life-threatening infections and malignancies. What is the typical median time period after initial infection HIV to progress to AIDS? 10 Years The rate of progression has been dramatically decreased with the use of this type of therapy. Antiretroviral therapies In the 1993 case definition, the CDC classified HIV-infected adults and adolescents into how many categories? Nine categories (A1–C3) In the association with clinical conditions found in HIV infections what are the 9 categories based on? CD4 T-cell counts HIV-infected individuals are classified as having AIDS if they have an absolute CD4 T lymphocyte of __ or ___? < 200/μL or certain opportunistic infections or malignancies indicative of AIDS What other types of symptoms besides opportunistic infections and Neurological symptoms
What method has a high of sensitivity and specificity, and may sometimes give erroneous results? ELISA Collection of the sample prior to seroconversion, to administration of immunosuppressive therapy gives what type of erroneous result? False-negative Replacement transfusion, to conditions of defective antibody synthesis such as hypogammaglobulinemia gives what type of erroneous result? Technical errors attributed to improper handling of kit reagents give what type of erroneous result? False-negative Heat inactivation of serum prior to testing, repeated freezing/thawing of specimens or presence of autoreactive antibodies give what type of erroneous result? History of multiple pregnancies, gives what type of erroneous result? False-positive Passive immunoglobulin administration gives what type of erroneous result? False-positive Severe hepatic disease, recent exposure to certain vaccines, and certain malignancies give what type of erroneous result? False-positive In low-risk populations, ELISA tests of HIV have what value? a low positive predictive value Probability that the patient truly has the disease if the test result is positive called: positive predictive According to a commonly accepted testing algorithm established by the CDC, when a sample screened for HIV antibody by yields a positive result what should be done? should be retested in duplicate by the same ELISA test If two out of the three specimens are reactive by ELISA, then the results must be confirmed by what more specific method? Western blot Regardless of results of confirmatory testing repeatedly reactive units of blood are not used for: transfusion What tests are ideal for use in settings in developing nations? Rapid screen ing tests
What are ideal for use in situations in which fast notification of test results is desired? Rapid screening tests Rapid results are important in guiding decisions to what? prophylactic therapy with antiretroviral drugs following occupational exposures Rapid tests are important in what case? testing women whose HIV status is unknown during labor and delivery Rapid tests are important in what case? testing patients in sexually transmitted disease clinics What tests are important in emergency departments who are unlikely to make a return visit for their test results? Rapid screening tests for HIV How many FDA-approved HIV screening tests commercially available in the United States? 6 Rapid HIV screening test’s kit can be used to test what in one method? serum, plasma, whole blood, and oral fluid While each test has unique features, all are lateral flow or flow-through immunoassays that produce what? a colorimetric reaction in the case of a positive result How is interpretation of HIV screening test made? through visual observation A reactive result is reported as: a preliminary positive A reactive result is reported as a preliminary positive and, like the standard requires confirmation by what more specific test? Western Blot Why positive result of ELISA should be confirmed by Western Blot? because of the possibility of false-positive results Methods that can test what sample for HIV antibody are not as accurate as the blood or saliva tests and must be confirmed with a standard serological test? Urine FDA has approved the use of what test kits in addition? Home test kits Which test for HIV antibodies was introduced in 1984 and has been used for systematic confirmation of positive ELISA results since 1985? The Western blot test, or immunoblot Although the Western blot technique is technically more demanding than ELISA, what can it provide? It can provide an antibody profile of the patient sample that reveals the specificities to individual HIV antigens present How are Western blot kits prepared? Commercially as nitrocellulose or nylon strips containing individual HIV proteins that have been separated by polyacrylamide gel electrophoresis and blotted onto the test membrane
This is accomplished by preincubating the patient specimen with human? Anti-HIV-1 antibody Anti-HIV-1 antibody is used for what assay? P24 If p24 antigen is present, the neutralizing antibody will form immune complexes and will prevent the antigen from binding to the HIV antibody on the? Solid support Absorbance should decrease by at least 50 percent on this test? Positive test In immune complexes, as the host produces antibody, what antigen becomes undetectable? P24 Primary screening for HIV-1 infection, p24 cannot replace this test? ELISA test for HIV antibody Quantitative tests for HIV nucleic acid is also known as? Load tests Load predict response to? Antiretroviral therapy load testing is performed by? Nucleic acid amplification methods load assays are based on? Amplification methods Viral load assays increase the number or what copies in test sample to detectable levels? HIV RNA copies What have been developed to diagnose HIV? Several amplification methods have been developed, including the reverse transcriptase polymerase chain reaction (RT-PCR) and real-time PCR, which amplify complementary DNA generated from HIV RNA; the branched chain DNA assay (bDNA), which amplifies a labeled signal bound to the test plate; and nucleic acid sequence-based amplification (NASBA), which amplifies HIV RNA. How many of polymerase chain reaction methods have been developed to detect HIV nucleic acid? Two: the reverse-transcriptase polymerase reaction (RT-PCR) and real-time PCR. Why do technical cares must be taken when performing the RT-PCR? Because this assay is susceptible to of test samples with amplicon, target DNA, or target RNA. What can be done to minimize Physically separate work areas should be designated for reagent preparation, sample preparation, amplification, and detection, and the work should flow in one direction only. More recently, real-time RT-PCR assays have been developed to do what? quantitate HIV RNA How amplicon are analyzed in these assay? They are analyzed at the same time they are produced (i.e., in real time). contamination