Prevalence of antibodies against Toxoplasma gondii and Neospora spp. in equids of Western Pará, Brazil

The present study aimed to determine the prevalence of antibodies against Toxoplasma gondii and Neospora spp. in equids raised for distinct purposes in the western state of Pará, Brazil, and to identify potential risk factors associated with parasite infection. A cross-sectional study was conducted with cluster sampling in 101 farms from 18 municipalities (farm horses). In visited municipalities, samples from sport and cart horses were included. Serum was obtained for detecting antibodies against T. gondii and Neospora spp. using indirect fluorescent antibody test, with a cut-off point of 1:64 and 1:50, respectively. Association analysis, using the chi-square test, was performed to evaluate possible risk factors related to the prevalence of antibodies. A total of 1298 equids were sampled (947 farm, 240 sport, and 111 cart horses), including 1244 horses, 2 donkeys, and 52 mules. The number of equids sampled per property ranged from 1 to 49. Of the total examined, 134 (10.3%) had antibodies against T. gondii, and of the 18 municipalities visited, 11 (61%) had at least one positive animal. Seventy-three of the 1298 equids (5.62%) from 44% of the municipalities tested positive for Neospora spp. The type of the animal (farm, sport, or carthorse) was not associated with the prevalence of antibodies against T. gondii; however, antibodies against Neospora spp. was more prevalent in carthorses (P = 0.001) (13.5%) than in farm (5.0%) and sport (4.6%) horses. Breed of the horse and the presence of cats were risk factors for the prevalence of antibodies against T. gondii, and presence of dogs was a risk factor for the prevalence of antibodies against Neospora spp. This is the first report of seropositive equids for T. gondii and Neospora spp. in the state of Pará contributing to the knowledge on epidemiology of the two parasites.