MYCVIR- MIDTERM HEPA HERPES

HAV

Picornaviridae; Hepatovirus; non-enveloped ssRNA virus.

HAV transmission

Fecal-oral route; contaminated food, water, and seafood.

HAV hallmark

Acute hepatitis; never causes chronic infection.

IgM anti-HAV

Marker of acute HAV infection.

HBV

Hepadnaviridae; Orthohepadnavirus; enveloped virus with partially double-stranded circular DNA.

Dane particle

Complete HBV viral particle; approximately 42 nm.

HBV transmission

Parenteral, sexual, and perinatal routes.

HBV chronicity risk

Approximately 90% in infected infants versus 3% in infected adults.

HBsAg

Marker of active HBV infection, carrier state, or incubation period.

Anti-HBs

Marker of recovery or immunity following HBV vaccination.

IgM anti-HBc

Marker of acute HBV infection; important during the diagnostic window period.

HBeAg

Marker of active HBV replication and high infectivity.

HBV P gene

Encodes DNA polymerase.

HBV S gene

Encodes HBsAg.

HBV C gene

Encodes HBcAg and HBeAg.

HBV X gene

Encodes HBx transactivator linked to liver cancer.

HCV

Flaviviridae; Hepacivirus; enveloped ssRNA virus.

HCV transmission

Primarily parenteral, including intravenous drug use and post-transfusion exposure.

HCV chronic carrier rate

Approximately 50%.

HCV diagnosis

HCV RNA detected by PCR; detectable in approximately 2 weeks.

HCV treatment

Direct-Acting Antivirals (DAA), which can cure infection.

HDV

Defective ssRNA Deltavirus that requires HBV HBsAg for its envelope and replication.

HDV superinfection

Can cause severe acute hepatitis with increased risk of cirrhosis and fulminant hepatitis in chronic HBV carriers.

HEV

Hepeviridae; Hepevirus; naked ssRNA virus.

HEV transmission

Fecal-oral route.

HEV hallmark

High mortality risk in pregnant women.

Herpesvirus structure

Large, enveloped linear dsDNA virus with an icosahedral capsid and tegument.

Herpesvirus hallmark

Lifelong latency with periodic reactivation.

HSV-1 latency

Trigeminal sensory ganglia.

HSV-1 hallmark

Oral herpes, herpetic keratitis, and temporal lobe encephalitis.

HSV-2 latency

Sacral sensory ganglia.

HSV-2 hallmark

Genital herpes, neonatal herpes, and aseptic meningitis.

Tzanck smear

Shows syncytial multinucleated giant cells with intranuclear inclusions in HSV infection.

Acyclovir

Antiviral treatment for HSV infection.

VZV / HHV-3

Varicella-zoster virus; causes chickenpox and shingles.

Varicella

Primary VZV infection; chickenpox.

Herpes zoster

Reactivation of VZV causing unilateral dermatomal shingles.

VZV latency

Dorsal root ganglia or cranial nerve ganglia.

EBV / HHV-4

Causes infectious mononucleosis and is associated with Burkitt lymphoma, Hodgkin disease, and nasopharyngeal carcinoma.

EBV receptor

CD21 / C3d receptor on B-lymphocytes.

EBV diagnosis

Monospot test; anti-VCA and anti-EBNA serology.

CMV / HHV-5

Characterized by enlarged cells with prominent owl's-eye intranuclear inclusions.

CMV hallmark

Owl's-eye intranuclear inclusions.

CMV clinical significance

Most common congenital viral infection; can cause retinitis, pneumonitis, and GI ulcers in immunocompromised patients.

HHV-6 and HHV-7

Roseoloviruses associated with roseola infantum (sixth disease).

Roseola infantum

High fever followed by a maculopapular rash as the fever subsides.

HHV-6 complication

Febrile seizures in approximately 30-40% of symptomatic young children.

HHV-7 receptor

CD4 molecule on T-lymphocytes.

HHV-8 / KSHV

Associated with Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman disease.

Kaposi sarcoma

HHV-8-associated vascular tumor characterized by purple skin lesions.