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81 Cards in this Set
- Front
- Back
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Enteroviruses include what group of viruses?
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Picornaviruses. It's the smallest of the RNA viruses.
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These viruses are all ssRNA +, Naked, nonsegmented (linear), icosahedral, with many antigenic types
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Picornaviruses
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Picornaviruses include what groups?
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Enteroviruses!
1. Poliovirus 2. Coxackie A and B 3. Echovirus 4. Hepatitis A 5. Rhinovirus |
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What common traits do enteroviruses share?
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They all cause CNS symptomology and grow in the gut
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How does the initial enterovirus infection take place?
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Takes place in upper respiratory tract and/or intestinal mucosa. These can withstand pH2. Viremia spreads from lymph system to blood and the virus has trophism for certain areas. They multiply in GI tract but don't actually cause a lot of diarrhea. It's secondary viremia is what goes to the CNS.
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Describe the illness brought on by poliovirus (ssRNA+ naked icosahedral)
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Aseptic meningitis, and abortive poliomyelitis. Poliomyelitis is an inflammation of gray matter in anterior horn of spinal cord, gives you flaccid paralysis. infects peyer's patches.
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What is post-polio syndrome?
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Ages 40-50, nerves that replaced the polio damaged ones wear out.
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What are the types of vaccines for polio?
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1. Salk Vaccine - inactivated virus that stimulates IgG but not IgA, prevents viremia but not intestinal infection.
2. Sabin Vaccine - live attenuated virus that is oral. Trivalent and stimulates production of IgA. Prevents viremia and intestinal infection. Will be shed so produces herd immunity. CAN revert back to virulence. US only uses killed vaccine. |
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Ho many antigenic types does polio have?
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3 - making it easy to have vaccine.
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What type of virus is coxackie A and what does it cause
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A picornavirus (enterovirus) that causes aseptic meningitis, herpangina, rash on hands and feet (C and D?)
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What type of virus is coxackie B and what does it cause?
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Picornavirus, causes neonatal encephalomyocarditis, myocarditis in adults, pleurodynia
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What type of virus is echovirus and what does it do?
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Picornavirus, enterovirus, it causes aseptic meningitis, febrile illness, summer exanthem (skin eruption) and can be caused in swimming pool.
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Why is it not practical to have a vaccine for echo and coxackie viruses?
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Too many antigenic types. Coxackie a has several, B has 6. Echo has up to 30.
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When are enteroviruses most prevalent?
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Summer and fall, worldwide distribution, 99% are subclinical.
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How do you diagnose enteroviruses?
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Usually serologically, by a rising antibody titer.
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This ssRNA + naked icosahedral virus is a member of the picornaviridae family and has over 100 antigenic types
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Rhinovirus, responsible for >25% of common colds
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What time of year is rhinovirus most active?
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late summer and fall
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Why is a vaccine against rhinovirus impractical?
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Immunity is short lived. There is less than 2 years immunity to each rhinovirus strain, due to IgA. There are also too many antigenic types.
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What type of treatment do we give for common colds?
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Decongestants, control secondary symptoms. Can give interferon, but it gives you same symptoms as cold.
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What type of virus is hepatis A?
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A picornavirus, an enterovirus
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How does HAV infect?
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Enters oropharynx, targets parenchyma of liver, replicates in hepatocytes and kupfers cells. Pathology is indestinguishable from HBV. Incubation period is 30 days (1 month). HAV is not cytolytic.
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In what hepatitis viruses is there chronic infection?
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HBV, HCV, HDV
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What is the incidence of jaundice by age group in HAV?
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less than 6 = 10%, 6-14 = 50%, >14 = 80%.
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What are the symptoms of HAV?
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fever, fatigue, nausea, loss of apetite, abdominal pain, jaundice. Not associated with hepatic cancer.
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What goes into making a hepatitis A vaccine?
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Culture it in fibroblasts, inactivate it with formalin, use aluminum hydroxide adjuvant, grow in eggs. Highly immunogenic (97%) with first dose. Vaccinate around 15 months. Should vaccinated if Hep A rate >20/100,000 and consider vaccinating if Hep A rate <20 but >10/ 100,000 people.
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Who can have the HepA/B vaccine?
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People >18yrs who need both hep A and B vaccination. Contains HbsAg and Hep A antigen. Vaccinated at 0,1, and 6 months.
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How do you diagnose a HAV infection?
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Acute = HAV-IgM, past = HAV IgG EIA
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What about hepatits A is different in the lab?
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It is difficult to culture, must use monkey kidney cells, and it is very hard to kill - goes to pH1, solvents, detergents ,salt water, drying, and high temps can't knock it out.
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What are the highest attack rates of HAV?
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In 5-14 year olds, children can serve as a reservoir for infection. Can be endemic in this age group.
Shellfish are also important because they are filter feeders and concentrate viral particles. |
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What is the source of HAV?
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Usually contaminated food, close personal contact, and rarely thru blood.
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This ssRNA + naked icosahedral virus has 4 genogroups with 25 types in each. It causes acute viral gastroenteritis.
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Calciviridae, Norovirus
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What type of virus is norovirus and how do you get it?
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A calcivirus, get it by fecal oral transmission, it infects and kills mucosal cells in the villi of small intestine leading to malabsorbtion.
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What ssRNA+ naked virus causes local epidemics of gastroenteritis?
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Norovirus.
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How do you treat norovirus?
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supportive with fluids and electrolytes. Must use proper hygeine. No vaccines at the moment, looking into using plants.
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What is so difficult about making a vaccine to norovirus?
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It tends to reinfect in the presence of high homologous Ab titers.
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How do you diagnose norovirus?
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Clinical evidence and exclusion, also has antigen capture kits for several serogroups
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This ssRNA + enveloped icosahedral virus is an arbovirus with a mosquito vector that gives rise to seasonal encephalopathy
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Alphavirus, a member of Togaviridae. Prevent by controlling its mosquito vector.
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EEE, WEE, VEE are all part of this virus, a member of Togaviridae
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Alphavirus. Severity = EEE > VEE > WEE.
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What are the symptoms of Eastern Equine Encephalitis?
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Malaise, headache, fever, vomiting. 50-70% death rate
Get life long immunity |
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What is the reservoir for alphavirus?
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Birds maintain the virus in nature. It uses a mosquito vector. In cold climates it overwimnters in reptiles, amphibians, migratory birds. Has a seasonal occurence.
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How do you diagnose alphavirus?
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4x rise in ab titer, isolation is difficult, must be from brain. Its seasonal nature makes it different than other encephalopathies.
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This ssRNA + nonsegmented enveloped icosahedral virus is an arbovirus with a mosquito vector that is responsible for 5 major illnesses.
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Flavaviridae, responsible for
Yellow Fever Dengue St. Louis encephalitis West Nile Virus Japanese Encephalitis |
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This helical ss RNA + enveloped virus has 4 antigenic types so far, and is newly discovered.
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Coronavirus, responsible for SARS and the common cold
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How is SARS spread and what are its clinical features?
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SARS - severe acute respiratory syndrome - is spread by inhalation of aerosol from person to person and direct contact. It initially starts as a cold, progresses to atypical pneumonia, 10% fatal.
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10-15% of cases of common cold are due to this SSRNA + helical enveloped virus
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coronavirus
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SARS-CoV has been isolated from what reservoirs in China?
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Domestic cats, wild dogs, wild cats. A possible source of initial infection.
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How do you diagnose coronavirus?
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Symptoms and evidence of local SARS outbreaks. Samples of URT, LRT, and tears are sent to govt labs for ELISA and direct IFA.
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How do you treat coronavirus?
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Interferon beta is effective in inhibition, vaccines not availble. Mostly need supportive care (respiratory, nutrition).
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This RNA +, icosahedral, enveloped virus contains a diploid viron of 2 ss RNA
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Retrovirus - HIV. In lentovirus subcategory.
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What two viral glycoproteins bind to the CD4 receptor on target cells in HIV?
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gp120 and gp41
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HIV contains premade reverse transcriptase to do what?
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This is RNA dependent DNA polymerase, to replicate thru a DNA intermediate and genome replication
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In what cells does the initial replication of HIV occur?
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Monocytes - macrophages (M-trophic) and CD4 T cells (T-trophic) and CNS dendritic cells.
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What is the infection process of HIV? What are the 3 stages?
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Early acute infection - mono like 30-60 days post infection with a massive increase in HIV in serum.
Steady state - set point of virus is detecatble in plasma, less than 10% the total virual load, maintained in T cells in lymph tissue. AIDS - CD4 count less than 200/microliter, often get opportunistic infections. |
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What are some typical symptoms of HIV infection?
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Chronic fever, fatigue, persistant diarrhea, pneumonia, chronic enlarged lymph nodes.
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What are some common opportunistic pathogens of HIV?
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Pneumocystis carnii, cryptosporidium, cryptococcal meningitis, toxoplasma gondii (ecephalitis), Candida, CMV encephalitis, JC Papovirus (PML), TB
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What malignancies are commonly associated with HIV?
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Kaposis Sarcoma, Burkitts Lymphoma, Non-hodgkins lymphoma in brain, leukemia, liver cancer, hodgkins, anogenital cancer from papovavirus.
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What two things serve as cofactors for binding HIV?
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CXCR4 - lymphocytes
CKR5 - Macrophages |
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This virus has 2 identical ss RNA pieces, protease, reverse transcriptase, and integrase. P24 is its major capsid protein.
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HIV, a lentovirus from Retroviridae, SS+ enveloped viruses.
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How do you diagnose HIV?
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First do an ELISA to screen, presumptive positive gets screened again by Western Blot to confrm. Viral load is then monitored by estimates of total body plasma levels of virus. Western blots separate out gag, pol, and env proteins.
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There are two types of HIV that occur, what are they?
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HIV 1 - throughout world, A-I clades with 3 outlier clades
HIV 2 - in West Africa, see A-E clades |
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What are the problems with creating an HIV vaccine?
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Rapid mutation, cell-> cell transfer of virus, Poor animal model
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What does HAART stand for?
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Hightly active anti-retroviral therapy, used in HIV
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What is the most prominent drug used to treat HIV?
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Reverse-transcriptase inhibitors.
NRTI - nuceleoside reverse transcriptase inhibitors, like AZT NNRTI - nonnucleoside reverse transcriptase ihibitors like nevorapine and efavirenz. NTRTI - like preveon |
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What do the drugs idinovir, saquinavir, and rionavir do to HIV?
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They are viral protease inhibitors.
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What ss RNA + enveloped icosahedral virus causes congenital defects in infants?
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Rubivirus, a member of Togaviridae
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What virus causes congenital defects in infants, also called the "3 day measels"?
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Rubivirus, causes Rubella
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Describe what infectious process happens in rubella
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In adults, you develop a macular rash with lymphadenopathy, fever, arthropathy. Spread by respiratory droplets.
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What virus leads to congenital rubella?
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Rubivirus, a member of togaviridae
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What does congenital rubella do?
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Causes spontaneous abortion, abnormalities, deafness, retinopathy, CNS retardation, heart defects. Risk goes down the farther along in pregnancy you are, 1st trimester = worst. Crosses the placenta easily in first trimester.
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Between 0-12 weeks of gestation, this virus has 100% chance of causing fetal abnormalities
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Rubella
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How do you diagnose rubella?
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Rising titers of IgG HAI, EIA, also presence of IgM.
For immune status screening, use EIA, HAI is not sensitive enough. |
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How do you treat rubella?
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Test all pregnant women for rubella status, do not give vaccine to pregnant women.
There is live attenuated vaccine, has 95% efficacy, in the MMR vaccine. 80% of women had been infected in pre-vaccination era. |
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This icosahedral double stranded segmented RNA virus causes gastroenteritis
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Reovirus, particularly rotovirus, a subdivision of reo
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This virus causes endemic viral gastroenteritis
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Reovirus, rotavirus
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Rotavirus' have how many antigenic types? Which one causes the most outbreaks?
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6 antigenic types, Type A is the worst.
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What is the pathogenesis of reovirus?
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Infects and kills villous epithelial cells in duodenum and proximal jejunum resulting in transient malabsorbption.
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50% of infantile gastroenteritis is caused by this organism?
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Rotavirus (reovirus). Adults are usually asymptomatic. A significant and deadly disease in hospital NICU facilities.
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How do you diagnose rotavirus?
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Can demonstrate in stool, cumbersome. Cannot grow in culture. Must do ELISA and rapid antigen test. Also could use electron microscope.
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What kind of vaccine is used for rotavirus?
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A live attenuated vaccine called rotatex. It is based on gentically engineered bovie rotavirus, and protects against five types of rotavirus.
Rotarix is another type, it is monovalent. |
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Why is it difficult to get rid of rotavirus?
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Because it can reinfect even in the presence of high homologous AB titers.
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When does rotavirus occur most?
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Winter.
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