Foodborne Illnesses / Hepatitis A /

Hepatitis A Food Poisoning

An Introduction to Hepatitis A

Viral hepatitis is a major global public health problem affecting hundreds of millions of people and is associated with significant morbidity and mortality. Five biologically unrelated hepatotropic viruses cause most of the global burden of viral hepatitis: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D (delta) virus (HDV), and hepatitis E virus (HEV). HBV, HCV, HDV, and, occasionally, HEV can produce chronic infections, whereas HAV does not.

The hepatitis A virus (HAV) causes an acute, self-limiting infection of the liver that is typically mild and resolves spontaneously. The clinical manifestations and duration of illness vary a great deal, with many persons, especially young children, showing no symptoms at all. The proportion of asymptomatic infections range between 30% in adults and up to 90% in children under age 5. The clinical signs of HAV infection include dark urine and, sometimes, clay-colored stool, often accompanied or followed by jaundice. Associated symptoms may involve fever, abdominal pain, loss of appetite, diarrhea, nausea, vomiting, headache, and extreme fatigue.

Hepatitis A was originally referred to as infectious hepatitis and understood to be transmitted differently than serum hepatitis (now known as hepatitis B). It has been written that the “earliest accounts of contagious jaundice are found in ancient China.” According to the CDC,

The first descriptions of hepatitis (epidemic jaundice) are generally attributed to Hippocrates. Outbreaks of jaundice, probably hepatitis A, were reported in the 17th and 18th centuries, particularly in association with military campaigns. Hepatitis A (formerly called infectious hepatitis) was first differentiated epidemiologically from hepatitis B, which has a longer incubation period, in the 1940s. Development of serologic tests allowed definitive diagnosis of hepatitis B. In the 1970s, identification of the virus, and development of serologic tests helped differentiate hepatitis A from other types of non-B hepatitis.
Until 2004, hepatitis A was the most frequently reported type of hepatitis in the United States. In the pre-vaccine era, the primary methods used for preventing hepatitis A were hygienic measures and passive protection with immune globulin (IG). Hepatitis A vaccines were licensed in 1995 and 1996. These vaccines provide long-term protection against hepatitis A virus (HAV) infection.

Hepatitis A is the only common vaccine-preventable foodborne disease in the United States. While it does not develop into chronic hepatitis, relapse of acute hepatitis A has been observed to occur in 3 to 20 percent of cases, sometimes with prolonged or persistent cholestasis (arrest of bile flow) after infection. Rarely, HAV has extrahepatic manifestations such as pancreatitis, rash, acute kidney injury with interstitial nephritis or glomerular nephritis, pneumonitis, pericarditis, hemolysis, acute cholecystitis, mononeuritis, Guillain-Barré syndrome, encephalitis, and central myelitis. HAV infection can precipitate autoimmune hepatitis.