Occupational Safety

Hepatitis A

(Infectious Hepatitis, Epidemic Jaundice, Catarrhal Jaundice, HA, HAV)

Humans are the primary reservoir for Hepatitis A virus (HAV), and nonhuman primate infections result from contact with infected humans. However, more than 200 cases of HAV infection in humans have been associated with nonhuman primates, and many nonhuman primate species are infected. A recent outbreak of HAV infection in young domestically reared rhesus macaques has renewed the concern for potential zoonotic transmission.

HAV is transmitted by the fecal-oral route, and some outbreaks can be related to contaminated food and water.

The disease in nonhuman primates is much less severe than the disease in humans, and is often subclinical. Some species of nonhuman primates develop malaise, vomiting, jaundice, and increased serum concentrations of hepatic enzymes.

The disease in humans varies from a mild illness lasting 1-2 weeks to a severely debilitating illness lasting several months. After an incubation period of about a month, patients experience an abrupt onset of fever, malaise, anorexia, nausea, and abdominal discomfort, followed within a few days by jaundice. Children often have a mild disease without jaundice, whereas HAV infections in older patients can be fulminant and protracted, with prolonged convalescence.

An approved vaccine (PDF) is now available for the control of HAV infection in humans. Passive immunization with immune serum globulin has also been used at intervals of 4-6 months for personnel in contact with recently imported chimpanzees.

The use of protective clothing, good personal hygiene, and appropriate sanitation of equipment and facilities also will minimize the potential for zoonotic transmission.