Toxoplasmic sheep abortion in a Florida farm

Abstract

An epizootic of Toxoplasma spp. sheep abortions in a farm in Florida, Uruguay, is described. Oocysts shed by domestic and wild cats inhabiting a big native forest were the likely sources old infection for sheep. In the 1993 lambing season, of 293 ewes that were tupped, 154 raised lambs and 18 aborted. Of 269 gimmers that were tupped, 107 aborted and none raised lambs. Toxoplasma spp. was isolated by mouse inoculation with homogenates of cotiledons and liver, spleen, lungs and brain of 3 aborted fetuses. 28 sera from sheep that aborted had titres of 1:16.384 or greater with the direct agglutination test of Desmonts and Remington; 2 more sera from the same group had titres of 1:1.024. White spots of necrosis the size of a pinhead were seen on the surface of placental cotiledons from ewes that aborted. Necrosis and calcification of cotiledonary villi and brain and hepatitis, neumonia and nephritis were the histological findings. Six months after the epizootie of abortions, 55.6% of the ewes had titres of 1:1024 or greater, which allowed the authors to consider that reproductive wastage due to toxoplasmosis could have been in a similar range. Experimental vaccination of ewes free of Toxoplasma infection was initiated, to protect them against reproductive wastage in 1994.