Exam 1 – Microbiology Answers – Flashcards
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| What are the three characteristics of viruses? |
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| structure, taxonomy, and replication |
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| What makes up virus structure? |
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| viral genome (nucleic acid), capsid (protein coat which surrounds the genome), virion (entire virus = nucleic acid, capsid, envelope, glycoprotein spikes), envelopes (lipid containing, larger viruses, surrounds the capsid) and morphology (helical = irregular shaped capsid, spiral shaped, icosahedral= cubical capsid with 20 flat sides and complex). |
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| What makes up Viral taxonomy? |
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| type of genome (can be DNA or RNA), the number of strands (single or double stranded), morphology (icosahedral, helical or complex) and the presence of absence of an envelope |
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| What are the stages in viral replication? |
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| attachment, entry, uncoating, replication, assembly, release |
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| attachment |
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| initiate the infectious cycle, virus recognizes and binds to a suitable host cell |
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| entry |
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| penetration- virus enters the host cell, fusion of the viral envelope with host cell membrane |
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| uncoating |
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| occurs once the virus is internalized, necessary to release viral genome before the viral DNA or RNA is delivered to its intracellular site of replication in the nucleus or cytoplasm |
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| replication |
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| macromolecular synthesis- production of nucleic acid and protein polymers |
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| release |
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| occurs following cell lysis or by budding from cytoplasmic membrane |
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| How are viruses classified? |
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| (1) morphology (2) type of genome or (3) means or replication |
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| How is a throat swab collected? |
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| rub inflamed vesiculated or purulent areas of the posterior pharynx with a dry sterile swab, avoid mouth |
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| What can throat swabs detect? |
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| enterovirus, adenoviruses and HSV |
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| How is a Nasopharyngeal swab/aspirate collected? |
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| insert swab through nostril to the nasopharynx or use a bulb syringe with saline and squirt into nose and aspirate back |
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| what can Nasopharyngeal swab/aspirate detect? |
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| respiratory syncytial, influenza and Parainfluenza. |
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| What can nasal specimens detect? |
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| rhinovirus |
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| Aspirates versus swabs |
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| nasopharyngeal aspirates are superior to the all swabs, but swabs are easier to get. |
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| How are Bronchial and Bronchoalveolar washes collected? |
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| wash and lavage fluid collected in bronchoscopy |
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| What can Bronchial and Bronchoalveolar washes detect? |
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| lower respiratory tract viruses (influenza and adenovirus) |
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| How are rectal swabs collected? |
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| inserting a swab 3 cm into the rectum to obtain feces. |
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| Rectal swab v. Stool specimen |
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| Stool specimens are preferred |
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| What can rectal swab and stool specimens be used to detect? |
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| rotavirus, enteric adenovirus, and enterovirus |
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| How are urine samples collected? |
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| Best specimen is 10 mL of clean-voided first morning urine. |
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| What can urine samples detect? |
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| used for CMV, mumps, measles, polyomaviruses and adenoviruses |
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| how are skin and mucous membrane lesions collected? |
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| Cannot collect after skin has ulcerated or crusted. Collection form cutaneous vesicles by unroofing the vesicle and aspirating the fluid. |
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| What can skin and mucous membrane lesions be used to detect? |
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| enterovirus, HSV, VZV, CMV and pox viruses |
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| How are sterile body fluids collected? |
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| collected aseptically by doctor |
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| What can sterile body fluid be used to detect? |
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| used for enterovirus, HSV, VZV, influenza, and CMV |
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| How is blood collected? |
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| 10 mL of anticoagulated blood in Vacutainer. Sodium citrate should be used |
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| What viruses can be detected in blood? |
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| CMV, HSV, VZV, enterovirus and adenoviruses |
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| How is bone marrow collected? |
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| aspirated specimens are added to a sterile tube with anticoagulant |
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| What is bone marrow used to detect? |
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| parvovirus B19 |
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| How is tissue collected? |
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| collected during surgical procedure |
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| What can tissue be used to detect? |
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| CMV, influenza virus, adenovirus, sin nombre virus, and HSV |
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| How is serum collected? |
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| collected as soon as possible after symptoms, 5 mL via venipuncture. |
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| What is serum used to detect? |
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| Antibodies |
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| How are specimens transported? |
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| placed on ice and transported to laboratory, if there is a delay it should be refrigerated for 12-24 hours, if longer you need to freeze the specimen at 4°C, for longer than 6 days freeze at -20°C |
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| Name the three kinds of tissue culture? |
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| primary (from animal tissue, limited divisions), diploid (more divisions but resistant to viruses) or continuous/ heteroploid cell (indefinite divisions, HeLa cells) |
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| cytopathic effect |
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| areas of dead or dying cells |
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| hemagglutination/hemadsorption |
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| infected cells contain viral hemadsorping glycoproteins in their outer membranes, if you wash the culture with red cells you see a ring around the infected cells |
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| immunostaining |
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| hemadsorption cell cultures stained with fluorescent-labeled antisera to identify the specific hemadsorping virus present |
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| Rapid viral antigen detection Advantages |
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| rapid, can detect viruses that can’t be cultured, do not need to culture |
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| Rapid viral antigen detection Disadvantage |
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| need to know what virus you are looking for, need correct specimen, labor intensive and costs more money |
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| Light microscopy |
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| less sensitive than culture but especially helpful for viruses that difficult or dangerous to isolate in the lab (parvovirus and rabies virus) |
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| Electron microscopy |
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| labor intensive, insensitive, works for viruses that do not grow in culture, can detect virus in small amounts, used for gastroenterovirus, HSV, and measles, can identify morphology |
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| Enzyme Immunoassay Advantages |
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| nonradioactive, stable reagents and results can be interpreted qualitatively and quantitatively, sensitive, simple, can be automated |
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| Enzyme Immunoassay Disadvantages |
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| borderline interpretive category for low levels of viral antigen, specimen quality cannot be evaluated, number of cells cannot be assessed, and cellular specimens are inferior. |
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| Nucleic acid probes |
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| can generate results in hours, probe reaction can occur in situ, usefully with abundant virus |
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| Gene amplification assays |
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| amplify DNA target sequences for probes, automated, rapid, broad application, introduction and use of standardized materials and external quality control programs, universal internal controls to ensure accuracy. |
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| Serologic Assays |
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| used to detect immune status and to make the diagnosis of infections in situations in which the virus cannot be cultivated in cell culture or detected readily by immunoassay or molecular assay. |
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| Immune status |
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| measures whether a particular virus has previously infected a patient |
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| The most common respiratory viruses (6) |
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| influenza, Parainfluenza, respiratory syncytial virus, adenovirus, rhinovirus and coronavirus |
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| The populations most at risk for RSV |
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| children under the age of 4 and caregivers of those children |
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| Antigenic drift |
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| is subtle changes, dependent on two characteristics: the duration of the epidemic, and the strength of host immunity. A longer epidemic allows for selection pressure to continue over an extended period of time and stronger host immune responses increase selection pressure for development of novel antigen, can lead to loss of immunity and explains the necessity for a new flu shot each year, occurs in all influenza viruses |
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| Antigenic Shift |
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| process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains, only occurs in influenza A because it can affect more than just humans |
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| The viruses associated with skin eruptions (exanthemas) (5) |
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| measles virus (rubeola), rubella (German measles), hand, foot and mouth disease, parvovirus, and Varicella. |
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| The six classic childhood rashes |
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| measles, scarlet fever, rubella, scalded skin syndrome (staphylococci), erythema infectiosum (parvovirus) and roseola infantum (herpes virus 6 or 7). |
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| The viruses associated with gastrointestinal infections (6) |
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| rotavirus, Noravirus, adenovirus (40 and 41), coronavirus, Caliciviruses, and Astroviruses |
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| The viruses associated with the CNS (4) |
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| poliovirus, coxsackievirus A and B, echovirus, and enterovirus |
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| The sexually transmitted viruses (9) |
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| Hepatitis B/C and delta, Herpes, Epstein-Barr, CMV, HPV, retroviruses (HIV), Filoviridae, and Orthopoxvirus |
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| Hepatitis A and E are transmitted |
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| fecal-oral route |
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| Hepatitis B/C and delta are transmitted |
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| infected blood/body fluids |
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| Antigenic Drift and Influenza A |
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| With respect to influenza A antigenic drift occurs when the virus mutates and develops a novel antigen. The hemagglutinins and neuraminidases stay the same |
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| Antigenic Shift and influenza A |
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| With respect to influenza A antigenic shift occurs when the virus completely changes hemagglutinins and neuraminidases (example spring 2009 Influenza A had components of swine, avian and human flu |
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| why are vaccines for influenza not always effective |
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| Vaccines for influenza are not always effective because the flu could have mutated during flu season and the vaccine does not cover that antigenic drift. |
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| List 6 respiratory viruses. |
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| Influenza viruses, Parainfluenza, Adenovirus, RSV, Rhinovirus, and Coronavirus |
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| What disease does influenza virus cause? |
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| respiratory illness (winter) characterized by high fever, headache, extreme tiredness, dry cough, runny/stuffy nose and muscle aches |
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| What disease does parainfluenza virus cause? |
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| year round upper respiratory (not severe cold) in adults and croup, bronchiolitis and pneumonia (which can be more serious) in children |
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| What disease does RSV virus cause? |
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| seasonal (dec/jan) bronchiolitis, pneumonia and coup |
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| What disease does Adenovirus cause? |
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| pharyngitis, conjunctivitis, pneumonia, cystitis, and gastroenteritis. |
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| What disease does Rhino virus cause? |
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| year round common cold (highest incidence in late winter/early spring). |
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| What disease does Corona virus cause? |
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| common cold and possible gastroenteritis |
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| Who is the primary population affected by influenza virus? |
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| 5-20% of the population |
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| Who is the primary population affected by parainfleunza virus? |
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| adults and children |
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| Who is the primary population affected by RSV? |
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| children < 4 |
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| Who is the primary population affected by adenovirus? |
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| military recruits |
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| What disease does mumps virus cause? |
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| swelling of the paracarotids, in males a swelling of the testes, and encephalitis |
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| Who is the primary population affected by mumps? |
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| older males, and school age children |
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| What is the diagnosis for influenza |
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| cell culture, antigen detection and PCR. |
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| What is the diagnosis for parainfluenza |
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| culture (via DFA) and PCR. |
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| What is the diagnosis for RSV |
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| cell culture, antigen detection and PCR. |
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| What is the diagnosis for adenovirus |
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| cell culture, antigen detection and PCR. |
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| What is the diagnosis for rhinovirus |
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| cell culture and PCR |
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| What is the diagnosis for coronavirus |
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| electron microscopy |
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| What is the diagnosis for mumps |
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| cell culture and serology |
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| List 6 viruses that cause gastrointestinal disease |
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| Rotavirus, norovirus, adenovirus (40 and 41), coronavirus, calicivirus and astrovirus |
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| How is rotavirus diagnosed? |
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| The common means for laboratory diagnosis are EIA and PCR. |
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| How is norovirus diagnosed? |
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| EIA and PCR. |
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| What types of infections do human papillomaviruses produce? |
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| skin and anogenital warts, benign head and neck tumors and cervical and penile cancer. |
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| Which viruses have the potential for latency? |
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| Adenovirus, Herpes Simplex Virus, Varicella Zoster Virus, Epstein-Barr Virus, CMV, HPV and retroviruses |
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| Where is the Herpes Virus latency? |
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| sensory nerve ganglia |
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| Where is the VZV latency? |
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| dorsal root ganglia |
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| Where is the Epstein-barr latency? |
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| B lymphs |
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| Where is the CMV latency? |
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| WBCs, endothelial cells and various organs |
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| Where is the HPV latency? |
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| epithelial tissue |
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| Where is the retrovirus latency? |
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| CD4 lymphocytes |
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| What are the markers for acute hepatitis B? |
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| Hepatitis B symptoms and the rising and falling levels of HBeAg, HBsAg antigens. The Anti-HBc and Anti-HBe antibodies will also increase during the acute infection |
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| What are the markers for chronic hepatitis B infection? |
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| steady level of HBsAg and total anti-HBc antibody |
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| What are the markers of resolution of a hepatitis B infection? |
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| decline in HBsAg and HBeAg an increase a steady level of Anti-HBc, a slight decrease in Anti-HBe and an incline in Anti-HBs. |
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| List the viruses for which a vaccine is available (10) |
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| Influenza A and B, adenovirus, Mumps, Measles Virus (Rubeola), Rubella, Varicella zoster Virsus, Human papilloma virus, Rabies (post exposure), Rotavirus (under development), Hepatitis A and B. |
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| acronym for respiratory viruses? |
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| IPARRC (influenza, parainfluenza, RSV, rhinovirus and coronavirus) |
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| acronym for exanthema viruses? |
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| CRP VM (crap vince mirab) Coxsackie viurs A4/10/11, rubella virus, parvovirus B19, varicella zoster, and measles (rubeola) |
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| acronym for gastrointestional viruses? |
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| NAC RAC- Norovirus, adenovirus (40/41), coronavirus, rotavirus, astrovirus and calcivirus |
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| acronym for arboviruses? |
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| BFT (big freaking ticks)- bunyaviridae, flavivirdae, and togaviridae |
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| Hepatitis virus types? |
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| A,B,C,E |
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| 4 H viruses? |
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| Herpes Simplex, Herpes 6 & 7, herpes 8, human papilloma virus |
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| acronym for other viruses? |
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| FORREV C- Filoviridae, orthviridae, reterovirus, ravies, epstein-barr, varicella zoster and CMV |
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| acronym for CNS viruses? |
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| PC2E2- polio, coxsackie a and b, enterovirus and echovirus |
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| ssDNA, no envelope, icosahedral? (1) |
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| parvoviridae family --> Parvovirus B19 (slap cheek syndrome, erythema infectiosum) |
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| dsDNA, no envelope, icosahedral? (3) |
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| Adenovirirdae- adenovirus (-itis +/- gastro), Reoviridae- rotavirus (winter, F/O transmission), or Papovaviridae (HPV) |
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| dsDNA, enveloped, icosahedral? (2) |
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| Hepadnaviridae- hepatitis B, or herpes virus (HSV, VZV, CMV, EPV) |
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| dsDNA, enveloped? (1) |
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| Small pox (orthopoxvirus) |
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| ssRNA, no envelope, icosahedral? (3) |
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| togoviridae (rubella, eastern/western/venezuelen encephalitis), flaviviridae (yellow fever/St. Louis fever from mosquitoes) or retroviridae- HIV |
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| ssRNA, no envelope, helical? (4) |
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| paramyxoviridae (parainfluenza, RSV and rubeola), coronaviridae (cold like +/- gastro), bunyaviridae (California encephalitis, LaCrosse disease, hantevirus and Crimean Congo hemorrhagic fever), or Rhabdoviridae (rabies) |
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| ssRNA, no envelope, segmented? (1) |
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| orthomyxoviridae- influenza A/B and C |
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| ssRNA, enveloped, round? (1) |
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| calciviridae- norovirus (cruise ships and nursing homes) and hepatitis E |
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| ssRNA, enveloped, defective? (1) |
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| delta virus |
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| ssRNA, eveloped, icosahedral? (1) |
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| picornaviridae- rhinovirus (cold), CNS viruses (PE2C2), and hepatitis A |
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| DNA viruses? (7 families) |
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| Smallpox, hepadnaviridae (Hep B), herpes family, adenoviridae, reoviridae (rotavirus), papovaviridae, and parvoviridae |
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| helical viruses? (4) |
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| ssRNA, and enveloped (all) paramyxoviridae, coronaviridae, bunyaviridae, and rhabdoviridae |
