Abstract

Hepatitis A virus (HAV) is a picornavirus that causes hepatitis A, a zoonotic disease. This virus has only human and nonhuman primates as its natural hosts. Just one serotype is known, but several strains have been recognized. The infection route of the HAV is fecal–oral. After the ingestion of the virus by infected food or contaminated objects, the virus replicates in the liver of the animal, reaches the intestines through the bile, and is eliminated with the feces. The disease in primates is mainly asymptomatic but when present is nonspecific and varies from mild signs to death. The diagnosis is made by serologic tests or identification from the viral antigen in sera or feces at the acute phase of the disease. The presence of anti-HAV IgM shows acute or recent infection. On the other hand, anti-HAV IgG is found from the convalescent phase of the disease through several years. The aim of this project was to research the seroprevalence of anti-HAV antibodies in New World primates and detect the viral antigen in feces from those animals that had acute infection. Sera from 421 animals of 32 different species were tested. From these animals, 13.5% (57/421) were wild animals, 29.7% (125/421) were from the Centro de Primatologia do Rio de Janeiro (CPRJ), 4.0% (17/421) from breeders, 3.8% (16/421) from Departamento de Parques e Áreas Verdes (DEPAVE), and 48.9% (206/421) were zoo animals. The sera were tested by immune-enzymatic tests for the presence of IgM and total anti-HAV antibodies. All the sera were negative for IgM, which means that no animal had acute infection when tested. All wild animals were negative for total anti-HAV, as were the animals from DEPAVE. Four percent (5/125) from the CPRJ animals and 7.6% (17/223) from the zoos’/breeders’ animals were positive for total anti-HAV, showing that a number of captive animals have already been in contact with the virus. The prevalence of anti-HAV antibodies found in this study was lower than expected, as it is known that the number of positive animals in captivity is high. The possible reasons for such low prevalence are discussed. Our results lead us to think that hepatitis A is not a disease of high risk for either wild or zoo New World primates kept in our conditions. To our knowledge, this is also the first report of hepatitis A in animals belonging to the genus Leontopithecus.

Acknowledgments

Financial support: Fundação de Amparo à Pesquisa do Estado de São Paulo—FAPESP.