Seroprevalence of Sarcocystis spp., Neospora spp. and Besnoitia spp. in horses (Equus caballus) intended for slaughter in the state of Rio Grande do Sul, Brazil.

Abstract

The study aimed to assess the prevalence of horses reactive to Sarcocystis neurona, Neospora caninum, and Besnoitia besnoiti in horses from the state of Rio Grande do Sul, Brazil. Sera reactivity was tested by the Immunofluorescent Antibody Test (IFAT) in 354 equids sampled at slaughter, using a cut-off of 1:80 for S. neurona and 1:50 for N. caninum and B. besnoiti. Detection of N. caninum was attempted by PCR and bioassay in gerbils (Meriones unguiculatus) using brain samples collected from seropositive horses. Sera from 158 horses (44.63 %) (158/354; CI: 39.54-49.84 %) reacted to S. neurona antigen, while 33 (9.32 %) (33/354; IC: 6.71-12.80 %) were reactive to N. caninum. Sera from 12 horses (3.38 %) were positive to N. caninum and S. neurona, 5 horses (1.41 %) were positive to S. neurona and B. besnoiti and 3 horses (0.84 %) were positive to B. besnoiti and N. caninum. None of the samples positive to B. besnoiti by the IFAT was confirmed by Western blot. Equine brain samples from horses seropositive to N. caninum were negative by PCR and bioassay in gerbils.