Strongyloides venezuelensis: effects of antimicrobial and immunosuppressive drugs during the course of infection in the AKR/J strain mice

Abstract

Groups of AKR/J strain of mice infected by Strongyloides venezuelensis and treated with Ceftazidima, Dexametasona or with both drugs concomitantly had been killed on 3rd, 7th and 12th day after infection and their lungs and intestines were processed for histological studies. In lungs of all infected groups, it was verified an inflammatory infiltrated (neutrophils and mononuclear cells) in the third day after the infection. In 7th and 12th day after the infection, the inflammatory reaction becomes reduced in control and antimicrobial treated groups, but not in immunosuppressed animals (with or without antimicrobial treatment). Analysis of the duodenal mucosa confirmed the presence of parasites in all groups of animals. On the 7th day after infection it was observed significant alterations in the small intestine of control (infected) and infected and treated with antimicrobial groups with presence of inflammatory foci, constituted by mononuclear and eosinophils in mucosa, associate to a large amount of parasites, mainly in the region of the epithelium and sub epithelium. Two others groups (infected and immunosuppressed mice with or without antimicrobial), did not present inflammatory process. Goblet cells were less evident in mucosa suggesting a reduction in mucous production. In the 12th day of the infection, the treated with antimicrobial and control groups presented a reduced number of parasites and a discrete inflammatory reaction in the small intestine while the immunosuppressed groups showed more parasites in duodenum. The permanence of the infection by S. venezuelensis in immunosuppressed animals was prolonged in relation to other groups, remaining until the 49th day after infection. The results indicate that the interference of treatments in the population of intestinal microbiota favours the parasitism by Strongyloides venezuelensis.