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71 Cards in this Set
- Front
- Back
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DNA Viruses
(Think HHapppy) |
Herpes, Hepadna, Adeno, Papova, Parvo, Pox. All icosahedral except Pox
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Enveloped DNA Viruses
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Herpes (icosahedral), Hepadna (icosahedral), Pox (box)
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Naked DS DNA Viruses
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Papova, Adeno, Parvo (the only single stranded DNA virus)
Think to get a PAP smear you must be naked |
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Double Stranded RNA
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Reovirus, naked
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Single Stranded RNA, Positive, Naked
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Picornavirus, Calicivirus. Both icosahedral.
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Single Stranded RNA, Positive, Enveloped
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Togaviridae (icosahedral),
Flaviviridae (icosahedral), Coronavirus (Helical), Retrovirus (helical). |
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Single Stranded RNA, Negative
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All are enveloped. All are Helical.
Bunyaviridae, Orthomyxovirus, Paramyxovirus Rhabdovirus Arenavirus Filovirus |
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All DNA viruses except this one replicate in the nucleus
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Poxviridae, which replicates in the cytoplasm
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These are the only 2 RNA viruses that replicated in the nucleus
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Retrovirus and Orthomyxovirus
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What does "infectious RNA" refer to?
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Infectious RNA is single stranded +, ready to make virus right away
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RNA Dependent RNA Polymerase
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Is made by SS+ RNA viruses, is carried pre-made by all SS- RNA viruses
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Icosahedral, DS DNA, Linear, 47 antigenic types.
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Adenovirus. The common cold, acquired by inhalation, may become latent.
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>50% of respiratory disease in military recruits, causing "Acute Respiratory Disease"
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Adenovirus. Types 1,2,3,4,7 most common types. Military does have a vaccine for it.
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This DS DNA virus causes keratoconjunctivitis and ARD
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Adenovirus.
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Hemagglutination for rat, monkey, and human erythrocytes diagnoses this DS DNA virus
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Adenovirus
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DS DNA Enveloped, 4 segments, One antigenic type, cross reacts with HSV
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Varicella Zoster - Alphaherpesvirus
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Alphaherpes viruses
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HSV, VZV.
Latent in nerves. Make multinucleated giant syncytial cells with intranuclear inclusion bodies. |
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Betaherpes viruses
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CMV, HHV6, HHV7. Latent in B cells.
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Gammaherpes virus
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EBV, HHV-8. Latent in B cells.
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What do all herpesviruses have in common?
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Latency or persistant infection following primary. Held at bay by cell mediated immunity. Also, you cannot tell the difference between herpesviruses under electron microscopy. See cell ballooning.
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Varicella Zoster Virus gains entry to the body via what?
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Respiratory tract. Stays latent in cerebral or posterior root ganglia.
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If you acquire this between weeks 0-20 of gestation, fetus could have scarring, limb hypoplasia, CNS and eye deficits, and death
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Varicella Zoster - congenital inffection. "Varicella Syndrome" - can cross placenta.
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What vaccine is used for varicella zoster?
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A live attenuated whole cell vaccine that is safe even with latency. VZV has only one antigenic varient.
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How do you diagnose Varicella Zoster
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By clinical symptoms, serology if an atypical presentation. Causes chickenpox and shingles.
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DsDNA, cross reactive with VZV, enveloped, icosahedral, usually subclinical
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Herpes Simplex Virus. 1&2 share 50-70% homology.
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Reactivation of this virus is triggered by stress, infection (especially pneumococcal), fever, irradiation, sunlight, and menstruation
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Herpes Simplex Virus
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What are the oro-facial problems associated with HSV infection?
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Acute gingivostomatosis
Herpes Labialis (cold sore) Ocular herpes HSV Keratitis (cataracts) |
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This occurs on the penis, vagina, cervix, anus, vulva, bladder, sacral nerve routes, and spinal meninges. Also on your bum. It is prone to secondary staph or candida infection.
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Genital Herpes, recurs 60% of the time, perianal area worst of all
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What are the 2 forms of HSV encephalitis?
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Neonatal -> liquefaction, 100% fatal. Acquired in passage thru birth canal or thru placenta. Need C-section.
Focal -> temporal lobe, 70% mortality without treatment. |
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This is a intense painful infection of hands, with bumps and ulcers on fingertips.
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Herpetic whitlow
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How do you diagnose herpes simplex?
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Usually clinically. Can to immunoflourescent scrapings of skin to tell difference between HSV and VZV. PCR for encephalitis. Serology is retrospective.
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This has the largest genome of any herpesvirus and is one of the most successful human pathogens. DSDNA, icosahedral, enveloped, 4 isomers.
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Cytomegalovirus, CMV. So named because infected cells become swollen.
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CMV likes to hide out latent in these types of cells
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B cells in bone marrow
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What are the major complications of CMV?
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Cytomegalic Inclusion Disease - congential, transmitted to fetus during all stages of pregnancy. Causes CNS problems, choroidretinopathy, deafness, etc
Immunocompromised patients - transplant recipients and AIDS, get pneumonitis, retinitis, colitis, and encephalopathy. Mononucleosis - but heterophil AB test is negative and you still see atypical lymphs in blood |
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What is the best treatment for CMV?
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Ganciclovir, offer abortion if congenital. There is NO vaccine for CMV.
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How is CMV transmitted?
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Perinatal infection by genital secretion or breast milk. Very successful vertically and horizontally.
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How do you diagnose CMV in the lab?
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Look for CMV inclusion antibodies or CMV antigens in nuclei of blood PMNS*. Lives in WBCs so it is best to culture buffy coat.
It is in urine of neonates and adults, but not pregnant women. Must be diagnosed by IgM or IgG in that case. |
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This large genomed DS DNA enveloped virus becomes very problematic with transplants. Up to 70% of people in developing countries are infected.
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CMV.
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Between HHV 6 and HHV 7, it's the one that actually causes a disease
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HHV 6 - causes Roseala Infantum - a disease of infants with spiking fever and mild rash, which can be complicated by encephalitis. 99% of the population is infected by both by adulthood.
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HHV 6 has two different types, what are they and what do they cause?
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A = linked to MS
B = Roseala Infantum Lays latent in T-cells |
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How do you diagnose HHV6?
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Clinically - for roseala infantum. Few labs can diagnose it. Can do serology if needed.
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Kaposis Sarcoma is linked with this DS DNA enveloped virus
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HHV-8, in 100% of KS cases. Prevalence of HHV8 is low in the general population, not ubiquitous.
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This herpesvirus has molecular piracy in that it has many genes found in human DNA.
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HHV8, a gammaherpesvirus
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This DS DNA enveloped virus has 2 peaks of infection, between 1-6, and then 14-20. 80-90% of adults are alread infected, and it tends to immortalize B cells.
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Epstein-Barr Virus. EBV. A gammaherpes virus that doesn't integrate into host DNA but forms circular episomes.
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Name 4 diseases caused by EBV
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Infectious mono (check with monospot, agglutinates sheep blood
Burkitts Lymphoma - restricted to areas with holoendemic malaria Nasopharyngeal carcinoma - often in China Immunocompromised patients - lymphoma, leukoplakia, NHL, fatal infectious mono (Ducan X-linked Lymphoproliferative Disorder) |
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A vaccine for this virus should not be a subunit vaccine, a live vaccine may actually be tumorigenic
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EBV. Vaccine should protect against mono, burkitts lymphoma, nasopharyngeal cancer.
Antigen = gp 340/220 |
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A heterophil antibody test, using sheeps blood to agglutinate, is a great for detection of this virus.
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EBV - also detection of anti-EBV IgM.
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What cell does EBV tend to immortalize?
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B cells - binds to C3d complement receptors
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Single Stranded DNA, naked
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Parvoviridae, B19 virus. The smallest icosahedral virus.
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Parvoviridae causes what disease?
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Fifth disease - rosy cheeks, fetal loss thru hydrops fetalis, severe anemia, CHF, edma, fetal death. Aplastic crisis, tarkets erythrocyte precursors. Spread by respiratory route
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The risk of fetal infection of parvoviridae is highest during what trimester?
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2nd. Minimal risk during 1st and 3rd. Does not warrent abortion because can treat in urtero with digoxin. 50% of women at child-bearing age are susceptible.
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Small Pox is caused by what DS linear DNA virus?
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Poxviridae. 2 strains = variola minor and variola major.
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What type of envelope does poxvirus have?
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A very large box envelope.
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What is very unique about poxviridae?
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It doesn't need a nucelus to replicate, it carries its own enzymes and replicates in the cytoplasm, just needs host cell's energy.
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This DS DNA enveloped virus has very strong bioweapon potential
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Poxviridae. Has been eradicated due to effective vaccine, no animal vectors, infection only with symptoms, prior infection giving immunity.
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The symptoms include small lesions that progress from pustules to scars, centrifugal rash involving face and extremities. It enters via respiratory tract and has caused the most deaths of any infectious disease ever
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Small Pox - there are two phases of viremia on day 3 and 8, invades reticuloendothelial organs.
The minor varient of this is molluscum contagiousum. |
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Jenner used cowpox to make a dirty vaccine to this disease.
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Smallpox
There are serious risks to the current vaccine, but those immune can autinoculate other people. |
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This DS DNA Naked virus is responsible for HPV and JC virus
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Papovavirus.
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What is JC virus?
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Linked to PML - progressive multifocal leukoencephalopathy - a leading cause of death in HIV. It is a papovavirus, similar to HPV, BK, and Simian Vacuolating Virus
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This is the second most common cause of mental handicap behind downs syndrome
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Congenital CMV - recommend abortion. hard to detect unless mom has a primary infection.
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This DS DNA virus has a circular genome, encodes reverse transcriptase, and replicates thru and RNA intermediate. It is enveloped and icosahedral, and is prevented by immunization
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Hepadnavirus - Hepatitis B
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Antibody to its HBs Antigen gives protective immunity
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Hepadnavirus - HBV.
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What are the antigens of hepatitis B?
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HBsAg - envelop associated, presence indicates disease
HBcAg - core antigen, on capsid. IgM to it = acute infection, IgG to it = chronic infection HBeAg - a soluble marker of core, if seen, means it is highly infective. AntiHbE means it's no longer replicating. |
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How is HBV maintained in the population?
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Asymptomatic carriers with chronic infection
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This DS DNA virus is enveloped and has an average 60-90 day incubation period.
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Hep B. Causes jaundice. If less than 5yrs, <10% get jaundice. If >5yrs, 30-50% get jaundice.
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What types of infection does Hep B cause?
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Chronic peristent hepatitis, chornic active hepatitis, acute hepatitis. Cirrhosis, hepatocellualr cancer. T cells recongoise virus and keep killing liver cells.
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Treatment for hepatitis B includes what?
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Interferon for HbE + carriers with active hepatitis.
Lamivudine - a reverse transcriptase inhibitor. Has tendency to relapse once stopped. |
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How do you prevent Hepadnavirus?
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vaccination with HbS antigen, Hepatitis B Ig within 48 hours of exposure, screen blood donors, use universal precautions.
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How is hepatitis B transmitted?
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Percutaneous permucosal - blood, body fluids. Pernatal is the main means of transmission.
Infants are at the highest risk for chronic infection. Adults are at a lower risk of developing chronic infection. Most are infected at birth or in childhood. |
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How does the lab diagnose hepadnavirus?
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1. Abnormal liver enzymes (transaminase high)
2. HbSAg - marker if infection 3. HbS antibody - documents recovery 4. Anti-Hbc IgM - new infection 5. Anti-HBc IgG - old chronic infection 6. HBeAg - replication 7. Anti-Hbe - low infectivity 8. HBV-DNA - active replication, disappears with succesful treatment If you see HbE and HbS - ongoing active infection Anti-HbS = patient is immune |
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In this infection, there is a window at 28 weeks where there is no surface antigen and no antibodies, so it is misleading
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Hepadnavirus - acute recovery
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