Protracted alanine aminotransferase levels in tamarins infected with hepatitis A virus.

Eighteen red-bellied tamarins (Saguinus labiatus), experimentally infected with hepatitis A virus (HAV), were followed for up to 1.5 years after initial challenge. Half of these animals developed protracted alanine aminotransferase (ALT) abnormalities, which lasted for between 23 and 55 weeks post-challenge. IgM anti-HAV was detected intermittently during the early phase of their relapsing hepatitis and never after return of ALT levels to normal. The possibility that these findings may be related to continued HAV replication, coinfection with another agent, or the result of an autoimmune phenomenon triggered by HAV are discussed.