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· Enterically transmitted
· No chronic sequelae
· Infectious hepatitis - hepatitis B, C, D viruses
· Blood and body fluid transmission
· Serious chronic sequelae
· Possible
First characterized in 1973
RNA virus (member of enterovirus group)
Present in large quantity in stool of infected individuals
Lesser quantities in serum and saliva
Can be grown in vitro
Clinical Features
· Incubation period 30 days (range 15-50)
· Often asymptomatic in childhood
· <10% icteric under 6 years of age
· 70-80% icteric in adolescence/adulthood
· Fulminant hepatitis is rare
· <0.5% mortality in children
· No known chronic sequelae or carrier state
· Immune serum globulin: Given ASAP within 14 days post exposure
· 80-90% efficacy
_ Vaccine
· 94-100% efficacy
· Recommended for high-risk individuals, such as travelers to endemic areas, homosexual or bisexual men, drug users, chronic liver disease, children in locales with high endemic rates
B Virus
Dane particle is probably complete virion and contains HBsAg
Incomplete forms (spherical and filamentous particles) also contain HBsAg
Virion cores (HBcAg) are contained within the incomplete forms
HBeAg exists in serum and on hepatocytes
_ Antigenic and Genetic Variation
· Multiple antigenic specificities of HBsAg are
- Mutations in "a" determinant inhibit anti-HBs
binding, may cause vaccine failure
· Multiple viral "quasispecies" exist in persistently infected hosts
- Pre-core (HBeAg) and core (HBcAg) mutants may be important in pathogenesis of persistent infection
| Concentration in Various Body Fluids | ||
| High | Moderate hepatitis C, hepatitis D, hepatitis E, liver disease, jaundice | Low/Not Detectable |
|
blood
serum wound exudates |
semen
vaginal fluid saliva |
urine
feces sweat tears breast milk |
· Incubation 60-90 days