Avaliação parasitológica e sorológica de coinfecção por Syphacia muris e Strongyloides venezuelensis

Abstract

The specie Strongyloides venezuelensis is a parasite of rodents used in the study of parasite host relationship in helminth infected animals due to their resemblance of the cycle of Strongyloides stercoralis. The Syphacia muris is a nematode found in large numbers in the cecum of laboratory rats. The present study aimed carry out assessment parasitological and the cross-reactivity among rats (Rattus norvegicus) Wistar naturally infected with S. muris and experimentally infected with S. venezuelensis. Forty animals were used divided into four groups of 10 animals for evaluating the parasite load by quantification of helminths recovered from the intestines of animals and quantification of eggs S. venezuelensis per gram of feces. For cross-reactivity ELISA and immunoblotting were used. In addition, thirty animals were used for comparison of diagnostic methods for S. muris using the methods HPJ, Willis and Graham. Was demonstrated that elimination of eggs as well as the amount female parthenogenetic of S. venezuelensis decreases significantly by coinfection for S. muris. The method of Graham was the most effective in the detection of S. muris infection in rats. In ELISA was observed high cross reactivity at the sera from all rats infected with S. muris front to the total saline extract of S. venezuelensis and all animals infected only with S. venezuelensis front to the saline extract of S. muris. By immunoblotting demonstrated cross reactivity of IgG antibodies in sera from animals infected only with S. muris and recognition eight bands in the saline extract of S. venezuelensis. Of these only the bands of 68 and 102 kDa were considered to be immunodominant in specific serum from animals infected only with S. muris. In the sera from animals infected with S. venezuelensis there was the cross recognition of seven bands, and the 36, 91 and 149 kDa demonstrated the major peaks of reaction. The adaptive immune response generated for S. muris may have influenced in the infection by S. venezuelensis in coinfected animals, decreasing the animal load parasitic. This fact can be explained by antigenic similarity between the parasites and cross protection by IgG antibodies to antigens initially generated by S. muris. Given this, the rats kept in animal facilities should be periodically evaluated, once that infections with S. muris may compromise and interfere with experimental results with S. venezuelensis.