Gastrointestinal parasites in free-ranging common marmosets (Callithrix jacchus Linnaeus, 1758) in the state of Sergipe, northeastern Brazil.

Ecological interactions resulting from human interference and environmental changes have implications for human health and the host animals involved in the parasite cycles. Considering the scarcity of surveys of the parasitic fauna of non-human primates in northeastern Brazil, the objective of this study was to investigate the infection by gastrointestinal parasites in free-ranging common marmosets (Callithrix jacchus) in the State of Sergipe. Fecal samples were collected from 52 animals captured in three protected areas. Most of the samples consisted of adult females and 57% were infected with at least one of the 12 identified parasite taxa. The most frequent intestinal parasite was Prosthenorchis sp., followed by Spiruridae, Entamoeba spp. and Strongylida order. The presence of gastrointestinal parasites was not dependent on sex, age or weight, although there was an association with the capture biome.

Serologic cross-reactivity between Sarcocystis neurona and Sarcocystis falcatula-like in experimentally infected Mongolian gerbils.

Sarcocystis neurona is the major cause of the equine protozoal myeloencephalitis (EPM) in the Americas and has opossums of the genus Didelphis as definitive hosts. Most isolates of Sarcocystis sp. shed by opossums in Brazil differ genetically from the known species of Sarcocystis. These Brazilian isolates behave similarly as Sarcocystis falcatula, which causes sarcocystosis in birds, and for this reason, have been classified as Sarcocystis falcatula-like. Genes coding for the immunodominant surface antigens SAG2, SAG3 and SAG4 of S. falcatula-like are similar to those from S. neurona. It is unknown the Sarcocystis species that causes EPM in Brazil, as S. neurona has never been genetically confirmed in Brazilian horses. All cases associated with EPM in Brazil were diagnosed by immunological tests, which are not specific for S. neurona infection. It is possible that S. falcatula-like may infect horses in Brazil. The aims of the current study were to test the susceptibility of gerbils (Meriones unguiculatus) to experimental infections with S. neurona and S. falcatula-like, and to investigate potential serologic cross-reactivity to these parasites by immunofluorescent antibody test (IFAT) and Western blot (WB). A total of 27 gerbils, distributed in five experimental groups (G1-G5), were employed in this work (G1: 4 negative controls; G2: 6 infected with S. neurona merozoites, G3: 6 infected with S. falcatula-like merozoites; G4 and G5 (5 and 6, respectively, infected with different doses of sporocysts). None of the 17 animals that seroconverted for the parasites in IFAT presented any visualized organism or Sarcocystis DNA in the examined tissues. No serologic cross-reactivity was observed using IFAT. However, sera from animals infected with S. falcatula-like and S. neurona presented the same pattern of antigenic recognition when S. neurona merozoites were used as antigen in WB, including reactivity to proteins of 30 and 16 kDa, regarded as specific markers for S. neurona-infected animals. Gerbils did not sustain infection by these parasites, although produced antibodies after inoculation. These results are suggestive that other animal species that are exposed to S. falcatula-like, including horses, may present serologic cross-reactivity to S. neurona in WB. IFAT was demonstrated to be more specific that WB for the detection of antibodies to S. falcatula-like and S. neurona in the experimental conditions of this study.