Incidência e análise da taxa de transmissão vertical de Toxoplasma gondii e Neospora caninum em ovinos

Abstract

Toxoplasma gondii and Neospora caninum are obligate intracellular parasites responsible for reproductive disorders in sheep. The aim of this study was to evaluate the kinetics of antibodies in ewes naturally infected by Toxoplasma gondii and Neospora caninum. Ewes in reproductive age composed the experimental groups. All animals were submitted to pregnancy diagnosis and serological monitoring to determine prevalence and incidence rates. Blood samples of the ewes (postpartum) and their lambs (pre-colostral) were collected to evaluate the vertical transmission rate. Serological monitoring of the ewes was performed using the ELISA, and research of IgG antibodies anti- T. gondii and N. caninum in lambs was performed by IFAT. Aborted fetuses tissue samples were collected for PCR. The initial prevalence of toxoplasmosis was 25.0 % (15/60) and the final 46.7% (28/60), with an incidence of 28.9% (13/45); N. caninum initial prevalence was 26.0% (13/50) and the final 72.0% (36/50), and the incidence rate of 62.2 % (23/37). The abortion rate was 37.5% (3/8) for T. gondii and no abortions cases by N. caninum. The vertical transmission rate for T. gondii was 38.9% and 15.4% for N. caninum. The results of this study indicate immune response alterations in ewes naturally infected by T. gondii, mainly in those that aborted. Moreover, it was observed the importance of the horizontal transmission on the infection incidence by coccidia, as weel as the importance of the congenital infection to the maintenance of the parasites in the flock analyzed.