[Development of an infection in monkeys as a result of their sequential natural and experimental exposure to the hepatitis A virus].

The development of spontaneous outbreak of hepatitis A (HA) among African green monkeys kept under strict isolation conditions was studied. It was shown that in the case of introduction of HAV the infection involved all the susceptible monkeys, running a course with and without any increase in the level of activity of serum alanine aminotransferase (ALT) After inoculation of commercial gamma-globulin only the infection without the ALT activity increase developed and some monkeys had no signs of HA at all. Experimental reinfection with HAV was produced in monkeys having anti-HAV titres of less than or equal to 1:3500.