County of Los Angeles
Department of Public Health
Acute Communicable Disease Control
313 N. Figueroa Street, Room 212
Los Angeles, CA 90012
Phone: (213) 240-7941
Fax: (213) 482-4856
E-Mail:acdc2@ph.lacounty.gov
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Acute Communicable Disease Control
Hepatitis A
Hepatitis A virus (HAV), a RNA-virus of the Picornaviridae family, is a
vaccine-preventable disease transmitted fecal-orally, person-to-person, or through
vehicles such as food. Signs and symptoms of acute hepatitis A include fever, malaise,
dark urine, anorexia, nausea, and abdominal discomfort, followed by jaundice.
Many cases, especially in children, are mild or asymptomatic. Sexual and household
contacts of HAV-infected persons are at increased risk for getting the disease.
The average incubation period is 28 days (range 15–50 days). Recovery usually occurs
within one month. Infection confers life-long immunity.
ACDC uses the CDC/CSTE criteria for acute hepatitis A to standardize surveillance of
this infection. The criteria include: 1) an acute illness with discrete onset of
symptoms and 2) jaundice or elevated aminotransferase levels, and 3) appropriate lab
tests to confirm laboratory criteria for acute hepatitis A diagnosis: IgM anti-HAV
positive, or a case meets the clinical case definition and has an epidemiologic link
with a person who has laboratory confirmed hepatitis A (i.e., a household or sexual
contact of an infected person during the 15–50 days before the onset of symptoms).
It was discovered in November of 2005, that one of the largest reporting sources of
hepatitis A inadvertently stopped reporting cases since September 2004. In November
2005, this source reported more than 300 positive tests going back more than a year,
which had to be investigated. For these reasons, the year 2005 was divided into two parts.
In the last 5 months, all cases were confirmed as acute hepatitis A if they met the
CDC/CSTE criteria, or if the case was unable to be interviewed, they had ALT
levels >300 (a marker of liver injury), or if their medical record indicated they had
signs and symptoms of hepatitis A.
Hepatitis A virus (HAV), a RNA-virus of the Picornaviridae family, is a
vaccine-preventable disease transmitted fecal-orally, person-to-person, or through
vehicles such as food. Signs and symptoms of acute hepatitis A include fever, malaise,
dark urine, anorexia, nausea, and abdominal discomfort, followed by jaundice.
Many cases, especially in children, are mild or asymptomatic. Sexual and household
contacts of HAV-infected persons are at increased risk for getting the disease.
The average incubation period is 28 days (range 15–50 days). Recovery usually occurs
within one month. Infection confers life-long immunity.
