INTRAGASTRIC INFECTION-INDUCED IN MARMOSETS (CALLITHRIX-JACCHUS) BY ABRAZILIAN HEPATITIS-A VIRUS (HAF-203)

Several species of non-human primates have been used in studies on exp erimental infection with hepatitis A virus (HAV). Attempts to infect a South-American marmoset (Callithrix jacchus) with a Brazilian HAV iso late (HAF-203) are described here. Four seronegative animals were inoc ulated intragastrically and one was sacrificed on day 11, 20, 47 and 6 2 after infection. One uninfected animal was included as control. Live r, small intestine, lymph node, spleen and kidney samples were collect ed for histological diagnosis and immunocytochemistry studies. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serum enz ymes and anti-HAV antibodies were monitored by a colorimetric procedur e (Abbott) and an enzyme immunoassay (ELISA), respectively. Feces were collected daily for HAV antigen (HAVAg) detection by ELISA. Increased levels of HAVAg were detected in hepatocytes 11 days after infection, with a gradual decrease during the course of infection. Shedding of H AVAg in feces was observed from the late incubation to the early acute phase (20th day to 47th day after infection). The end of the incubati on period was indicated by the initial increases in serum ALT and AST. Severe hepatic lesions such as piecemeal necrosis and bridging necros is were detected during the acute phase, coinciding with the maximum t ransaminase levels and the appearance of anti-HAV antibodies. On the 6 2nd day (convalescent phase), the hepatic tissue showed evidence of re generation and the transaminase values had returned to baselines. The serological, biochemical, antigenic and histological evidence of hepat itis A was similar to that observed in several primate models inoculat ed with other HAV isolates. These data suggest that C.jacchus can be a valuable model for the study of hepatitis A and for the evaluation of HAV vaccines.