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90 Cards in this Set
- Front
- Back
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Herpesviridae - structure
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enveloped viruses with icosahedral capsids
**layer of protein (tegument) between capsid and envelope |
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Herpesviridae - size?
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big - 100-300 nm in diameter
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Herpesviridae - genome
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large, linear dsDNA (100-230 kbp)
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Herpesviridae - Important Family Members
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HHV1 - herpes simplexvirus-1 (HSV1)
HHV2 - herpes simplexvirus-2 (HSV2) HHV3 - Varicella-Zoster Virus (VZV) HHV4 - Epstein-Barr Virus (EBV) HHV5 - Cytomegalovirus (CMV) HHV6 + HHV7 HHV8 - Kaposi's Sarcoma Herpesvirus |
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HSV1, HSV2 and VZV belong to which subfamily?
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Alphaherpesvirinae
(remain latent in neuronal tissue!) |
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CMV, HHV6 (and probably HHV7) belong to which subfamily?
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Betaherpesvirinae
(establish latency in cells of immune system) |
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EBV and HHV8 belong to which subfamily?
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Gammaherpesvirinae
(****ONCOGENIC potential) |
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Does HSV1/HSV2 kill neurons?
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NO!
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HSV1/HSV2 infect which cells?
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epithelial cells and neurons innervating infections site
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HSV1/HSV2 - axonal transport
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virus travels by retrograde transport to ganglia where virus establishes latency
**oral - trigeminal ganglia **genital - sacral ganglia |
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What can reactivate HSV1/HSV2 latent infections?
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stress, UV, hormones, medical school, etc.
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What happens when HSV1/HSV2 is activated?
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virus travels from ganglia to initial site of infection, where lesions are produced.
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HSV1/HSV2 relies on what to avoid the immune system?
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cell to cell spread
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HSV1/HSV2 v. epithelial cells
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cause disease by direct cytolytic killing of epithelial cells
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Herpes simplex lesions... are those contagious?
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omigod... YES!
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Why do we care if a pregnant woman has HSV1/HSV2?
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Congenital herpes is bad news - disseminated infection, sepsis, death, etc.
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Herpes labialis oral
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HSV1 causes cold sores, fever blisters
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Herpes labialis genital
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HSV2 causes genital lesions
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Herpes whitlow
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finger infection
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Herpes gladiatorum
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skin infection in wrestlers and rugby players
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Herpes keratitis
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eye infection that can lead to recurrent damage and blindness
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Herpes encephalitis
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acute febrile disease with high morbididty and mortality
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Herpes meningitis
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often a sequalae of genital herpes -- self resolves
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Is HSV1 common?
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Yes - pretty much everyone has been exposed by age 2.
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Is HSV2 common?
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Yes - 5 of every 12 adults in the US
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HSV1/HSV2 diagnosis
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often diagnosed solely on vesicular lesions and location
Virus isolation is easy and fast (ELVIS) PCR and serological tests can discriminate 1/2 |
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HSV1/HSV2 treatment
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Acyclovir + analogues
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How does Acyclovir work to inhibit HSV1/HSV2?
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Nucleoside analogue -- non-toxic in prepared form, must be modified by thymidine kinase.
When incorporated into DNA, it disrupts viral DNA replication. |
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Acyclovir - resistance?
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Point mutations in viral DNA polymerase confer resistance
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____ ____ ____ is essential in controlling simplexvirus infection.
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cell mediated immunity
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HSV1/HSV2 - vaccine?
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nope (cell-to-cell, so titers don't really help)
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VZV - one of the childhood ____
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rashes
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VZV causes what common childhood rash?
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chickenpox (varicella)
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Name two ways VZV differs from most herpesviruses.
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1) VZV is a RESPIRATORY virus
2) VZV spreads through the body by VIREMIA |
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VZV establishes latency in ____.
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neurons
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VZV - infection route
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infection from aerosol virus
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VZV - where does infection begin?
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respiratory tract
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VZV is spread via ____ to the reticuloendothelial system.
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lymphatics
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VZV spreads through the body via ____.
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viremia
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____ ____ ____ is necessary to clear VZV
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cell mediated immunity
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What limits viremia and spread of VZV?
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humoral immunity
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____ causes a dermal vesiculopusular rash as the result of secondary viremia
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VZV
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VZV - is that rash contagious??
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YES!
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Shingles - cause?
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Reactivaition of herpes zoster (VZV) in neurons.
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Why is shingles seen primarily in older adults (and really freaked out med students)?
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Viral rash may be result of reduction in immune system competence
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Chickenpox - symptoms
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mild disease in children - fever and characteristic rash with successive waves over 3-5 days
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VZV - incubation period
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14 days (until rash)
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VZV - more serious in adults?
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YES!!
immunopathology in primary infection, inflammatory reactions, interstitial pneumonia (20-30%) |
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Zoster - clinical diagnosis
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diagnosed by symptoms
rash limited to dermatome severe pain precedes rash postherpetic neuralgia |
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____ ____ can be used to diagnose VZV infection in the laboratory
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cell cytology
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VZV - treatment
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Acyclovir, passive immunization
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VZV - vaccine
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life attenuated vaccine (also as prophylactic)
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CMV - size
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BIGGEST herpesvirus - 200-300nm in diameter with genome >200,000bp
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Does CMV often cause disease in immunocompetent folks?
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nope
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CMV - pathology
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establishes latency in mononuclear cells, lymphocytes, kidneys and heart
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___ is the most significant viral complication in organ transplantation.
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CMV
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___ is the most likely viral cause of congenital disease in a fetus.
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CMV
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CMV - congenital infection
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0.5 - 2.5% infected before birth
Infants at highest risk if mother had PRIMARY infection during pregnancy --> microcephaly, intracerebral calcification, hepatosplenomegaly, etc |
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CMV - cytoplasmic inclusion disease
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nuclear inclusion bodies in infected cells (esp salivary glands)
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CMV Mononucleosis
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mild, result of primary infection in young adults
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CMV - what happens to immunocompromised hosts?
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chemically immunosupressed transplant patients and AIDS patients -- wide range of disease: pneumonia, retinitis, colitis, organ rejection
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CMV - lab diagnosis
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histology, virus load, virus isolation, serology
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CMV - histology
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giant cell pneumonia in lung biopsy
enlarged cells with "owl eye inclusion body" |
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CMV - virus load
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**pts only treated with viral load is VERY high.
pp65 antigenemia assay, PCR, FACS |
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CMV - virus isolation
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routinely done in 1st week after birth
urine sample direct detection w/in 24-48hh |
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CMV - Serology
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primary infection detected by presence of IgM or by seroconversion
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CMV - treatment
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1) Gancyclovir - acyclovir analogue -- SIDE EFFECTS!!
2) Foscarnet - inhibits viral DNA polymerase |
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CMV - vaccine?
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nope
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HHV6 causes which of the childhood rashes?
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Roseola
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HHV6 - symptoms
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high fever 1-2dd followed by generalized rash 1-2dd
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HHV6 may cause mild ____ in naive adults.
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mono
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HHV7 - do we care?
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no - no associated disease
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EBV - causitive agent of ____ ____
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infectious mono
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EBV - limited to growth in which human cells?
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B cells, some epithelial cells
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EBV - how does it attach to hosts??
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VAP attaches to host CR2 (CD21) receptors
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EBV - what nuclear antigen is produced during latency?
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EBNA - EBV nuclear antigen
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EBV - direct/indirect pathology?
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indirect pathology by overstimulating immune system
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Infectious Mononucleosis - marker
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heterophile antibody
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Infectious Mononucleosis - symptoms
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high fever, malaise, hepatosplenomegaly, etc.
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Infectious Mononucleosis - complications
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Guillain-Barre syndrome and meningoencephalitis
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Burkitt's Lymphoma
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EBV - B-cell lymphoma of the jaw and face
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Epstein-Barr - transmission
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saliva
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EBV - Diagnosis
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Lymphocytosis - Mononuclear cells are 60-70% of WBC with 30% atypical lymphocytes
Heterophile antibody (Monospot test) Serology |
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EBV - treatment? antivirals?
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no antivirals, supportive care
***NO CONTACT SPORTS!!! |
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EBV - vaccine?
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nope
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HHV8 - responsible for ____ ____ in AIDS pts
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Kaposi's sarcoma
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HHV8 - (2) diseases
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Kaposi's sarcoma
Castleman's disease |
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Is HHV8 common?
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antibodies in 10% of population
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Monkey B Virus
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virus replicates in hindbrain --> 80% mortality
Results from monkey bite... no human-human transmission |
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Monkey B Virus - treatment
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prophylactic acyclovir
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