Foodborne Illnesses / Hepatitis A /

Symptoms of Hepatitis A Infection

What are the symptoms of Hepatitis A infection?

Hepatitis A may cause no symptoms at all when it is contracted, especially in children. Asymptomatic individuals may only know they were infected (and have become immune, as infection gives lifelong immunity) by getting a blood test later in life.

Approximately 10 to 12 days after exposure, HAV is present in blood and is excreted via the biliary system into the feces. Although the virus is present in the blood, its concentration is much higher in feces. HAV excretion begins to decline at the onset of clinical illness and decreases significantly by 7 to 10 days after onset of symptoms. Most infected persons no longer excrete virus in their feces by the third week of illness, although children may excrete HAV longer than adults.

Figure 3. Timeline for hepatitis A manifestations.

The average incubation period for HAV is between 2 and 4 weeks (but can be up to 8 weeks). Signs and symptoms, as described above, typically begin about 28 days after contracting the virus, but can begin as early as 15 days or as late as 50 days after exposure. Jaundice (i.e., icterus) is a clinical sign that appears relatively later on in an HAV infection—after a few days to a week of typical symptoms. A sign of “cholestasis,” jaundice, manifests as yellowing of the skin, eyes (“scleral icterus”), and mucous membranes. It is caused by bile flowing poorly through the liver, backing up into the blood, and resulting in the characteristic yellowish tint to the tissues. The same mechanism causes the urine to turn dark tea- or cola-colored because of the presence of bile, and the stool may turn white or clay-colored from the absence of bile.

Scleral icterus

In general, symptoms usually last less than two months, although 10 to 15 percent of symptomatic persons have prolonged or relapsing disease for up to six months. It is not unusual for blood tests to remain abnormal for six months or more (see ALT, IgM, IgG in Figure 3 above). The jaundice so commonly associated with hepatitis A can also linger for a prolonged period in some infected persons—sometimes as long as eight months or more. Bilirubin rises soon after the onset of bilirubinuria (bilirubin in the urine) and follows rises in ALT and AST levels. Serum bilirubin levels may be impressively high and can remain elevated for several months; persistence beyond three months indicates cholestatic HAV infection. Additionally, pruritus, or severe itchiness of the skin, can persist for several months after the onset of symptoms. These conditions are frequently accompanied by diarrhea, loss of appetite, and extreme fatigue.