Aspectos clínicos, patológicos e reprodutivos da infecção experimental por Toxoplasma gondii em caprinos

Abstract

The objective was to evaluate the clinical, pathological, and reproductive aspects of the Toxoplasma gondii experimental infection in goats. Firstly was studied the transmission T. gondii in goats inseminated vaginally with semen contaminated with strain tachyzoites CPG (genotype III). Were divided into two experimental groups (G1 and G2) each with five goats. The females of the G1 were inseminated with semen containing 1x105 tachyzoites and females G2 (control) with semen free tachyzoites (insemination = day 0). To confirm infection were performed serologic tests (indirect immunofluorescence) and detection of parasitic DNA (polymerase chain reaction) in blood and organs. For monitoring pregnancy ultrasound exams were used. In G1, seroconversion occurred between days 7 and 14 at 4/5 goats. In the same group, the DNA of T. gondii was present between days 7 and 49 in blood and various tissues of 3/5 goats and two kids born at full term. In G2, all samples were negative for both techniques. In the second experiment, the goats of the G1 in the first experiment were monitored in the acute and chronic phases of infection; embryonic reabsorption occurred in 4/5 goats in the acute phase, while in the chronic phase were observed in anestrus 2/5 goats, 1/5 goats had both hydrosalpinx and ovarian cysts. The third experiment investigated to venereal transmission of T. gondii in goats mated with breeder experimentally infected orally with oocysts of the ME-49 strain. Ten goats were allocated into two groups (G1 and G2) each with five animals. The female goats in G1 were mated with a breeder that had been experimentally infected with T. gondii oocysts whereas those in G2 (control) were mated with a serologically negative goat. The infection of the breeder and the females was confirmed through clinical, serological, molecular and histopathological findings. Seroconversion ocurred in the breeder infected on the 7th day post-infection (d.p.i.) and T. gondii DNA was present in the blood and semen in the 3th d.p.i. In G1, 2/5 goats seroconverted and DNA was present in the blood in 2/5 goats. In G2, all goats were negative in all tests. With regards to gestational development, the goats in G1 ocurred embryonic reabsorption in 1/5 in day 34 after mating, 1/5 aborted in day 42 after mating and 3/5 goats gave birth to full-term healthy kids. One of the kids exhibited PCR-positive blood at birth. In total, 2/5 of the females in G1 and 4/5 of the kids born alive in G1 exhibited PCR-positive in at least one organ. In G2, the goats gave birth goats healthy. In conclusion, artificial insemination with semen containing tachyzoites of T. gondii infected goats, causing reproductive pathologies during acute and chronic phases of infection. Furthermore, it was found that venereal transmission of T. gondii occurs in goats mated with an infected breeder.