HEPATITIS A

Description

Caused by the hepatitis A virus, (HAV), the onset of illness is usually abrupt with fever, fatigue, loss of appetite, nausea and abdominal discomfort follow by jaundice within a few days. The disease varies in clinical severity from a mild illness lasting 1-2 weeks, to a severe disabling disease lasting several months. Severity of illness increases with age but complete recovery without relapse is the rule. Generally hepatitis A is considered a disease with a relatively low case fatality rate ranging from 0.1 to 1.8% in adults over age 50.

Where are they found?

Humans are the primary reservoir however swine and birds are likely sources of new human subtypes thought to emerge through genetic changes.

How do we get infections?

Person to person by the fecal-oral route. Common source outbreaks have been related to contaminated water, food contaminated by infected food handlers, raw or under cooked shell fish and contaminated produce such as lettuce, cantaloupes, strawberries and apple cider.

In developed countries disease transmission is frequent among household and sexual contacts of acute cases and also occurs in day care centers with diapered, asymptomatic children. In the USA, 33% of the general population has serologic evidence of prior HAV infection.

Incubation period

Fifteen to 50 days with the average being 28-30 days. Evidence indicates that maximum infectivity occurs during the later half of the incubation period and continues for a few days after the onset of jaundice. Most cases are probably noninfectious after the first week of jaundice, however viral excretion of up to 6 months have been documented in infants and children. Chronic shedding of HAV in feces does not occur.

Treatment

Report to local health authority.

• Isolation, follow enteric precautions for proven HAV infection for the first 2 weeks of illness, but no longer than 1 week after the onset of jaundice.
• Immunize contacts with immune globulin (IG) (IM) 0.02ml/kg of body weight as soon after exposure as possible.

Prevention

Improve sanitary and hygienic practices to eliminate fecal contamination of foods and water.

• Outbreaks in institutions may warrant mass prophylaxis with IG and consideration of hepatitis A vaccine use.
• Clean and disinfect surfaces using an EPA approved disinfectant used according to the manufacturer's recommendation.