DNA Viruses Flashcards
Enveloped hepadnavirus, common cause of acute viral hepatitis, becomes chronic in 10% adults, transmission to 90% infants, increases risk of hepatocellular carcinoma and cirrhosis
Hepatitis B Virus
Hepatitis D is a defective RNA virus. Which part of HBV does it seek out to become pathogenic?
HBsAg
What are the first antibodies to appear in an acute Hepatitis B infection?
HBcAb. Positive during window phase; if HbcAb IgM is present, this indicates a recent disease
Which antigen indicates transmissibility of HBV infection and determines active state in chronic hepatitis?
HBeAg
- if HBeAb is instead present, this indicates that the infection is chronic but not active
If HBsAb is present, what phase is the patient in?
Either immunized or has a history of a prior infection (HBeAb and HBcAB IgG will also be present in case of prior infection)
ssDNA, naked icosahedral parvovirus, erythema infectiosum, causes flu-like symptoms with facial rash and sometimes arthralgias due to a Type III hypersensitivity (immune complex deposition), no vaccine available
B19
How does B19 infect and in which patients can this be a serious issue?
Infects immature erythroid progenitor cells, which results in cell lysis. Usually asymptomatic but in patients with sickle cell, can cause aplastic crisis.
dsDNA, naked icosahedral, many serotypes, infects basal layer of skin and mucous membranes and causes a hyperkeratosis, associated with warts and condylomata acuminata, some serotypes are premalignant (cervical intraepithelial neoplasia)
Human papilloma virus
koilocytic cells on Pap smear
Human papilloma virus
Serotypes 6 and 11 = benign, more common
Serotypes 16, 18, 31, 35 are preneoplastic; genes E6 and E7 inhibits p53 and Rb
Gardasil recombinant vaccine covers 6, 11, 16, 18
Polyomavirus, causes renal disease in AIDS patients
BK Virus
Polyomavirus, infects oligodendrocytes and causes demyelination, causes progressive multifocal leukoencephalopathy in AIDS or transplant patients
JC Virus
Also on differential: subacute sclerosing panencephalitis, prions
dsDNA, nonenveloped, many serotypes, penton fibers act as hemagglutinin and are also directly toxic to cells, virus is lytic in permissive cells and can be transformative/oncogenic in nonpermissive cells, causes pneumonia in military, pharyngoconjunctivitis in kids at swimming pools
Adenovirus
10 yo boy presents with painful urinating and blood in urine. He has no other symptoms and does not have a history of a recent illness.
Acute hemorrhagic cystitis, caused by adenovirus. Differentiate from Post-strep glomerulonephritis which is much more serious
What kind of vaccine is available for adenovirus?
Enteric coated live, nonattenuated vaccine used in the military
dsDNA, enveloped icosahedral, contains intranuclear inclusion bodies, establishes latency in nerves
Herpesviridae (HSV 1 and 2, VZV, EBV, CMV, HHV6, HHV8)
Cause of gingivostomatitis, cold sores, keratoconjunctivitis
HSV1, establishes latency in trigeminal ganglion
Fever, headache, confusion, focal temporal lesions, perivascular cuffing, high mortality rate if untreated, leading cause of viral encephalitis in US
HSV1
Cause of genital infections, severe neonatal infection during passage through birth canal
HSV2, establishes latency in sacral ganglion
Diagnosis of herpes genital infections?
Tzank smear to show multinucleated giant cells and Cowdry Type A intranuclear inclusions
Causative agent chickenpox and shingles, dewdrops on rose petals, latency in dorsal root ganglion, live attenuated vaccine available with boosters, diagnose with Tzanck smear
Varicella Zoster Virus
How can you differentiate a chickenpox rash from a smallpox rash?
Chickenpox: asynchronous (macules, vesicles, and scabs will all be present at same time)
Smallpox: synchronous (rash will be in same stage)
Latent infection of B cells by binding to CD21 and produces atypical reactive T cells (known as Downey Type II cells)
Epstein-Barr Virus
Malignancies associated with EBV
Burkitt lymphoma (c-myc), nasopharyngeal carcinoma, Hodgkin lymphoma
Diagnosis of EBV
heterophile antibody positive (IgM), serology (EBNA associated with transformed cells)
