Detection of Neospora spp. and Sarcocystis neurona in amniotic fluid and placentas from mares

The closely related apicomplexa protozoa, Toxoplasma gondii, Neospora spp., and Sarcocystis neurona, have all been associated with neurological and reproductive diseases in horses. However, there is limited data regarding the presence of these three parasites in equine placental tissues and amniotic fluid. The aim of the present report was to investigate the presence of the DNA of T. gondii, Neospora spp. and S. neurona in placentas and amniotic fluid in mares. Anti-T. gondii, anti- S. neurona and anti- Neospora spp. antibody titers were evaluated in 31 mares in the final third of pregnancy by indirect fluorescent antibody test (IFAT). The presence of parasite DNA in placentas and amniotic fluid was evaluated by polymerase chain reaction (PCR), using two target loci (ITS1 and Nc5). No antibodies to were identified nor was any T. gondii DNA detected in any mare. Antibodies to Neospora spp. were found in 6 mares (19.35 %) and DNA from this protozoan was detected in four placentas (12.9 %) and in five amniotic fluid samples (16.6 %). Antibodies to Sarcocystis spp. were detected in nine mares and S. neurona DNA was found in only one placenta (3.23 %). Our results suggest that the transplacental route may be a potential source of Neospora caninum infection in mares. Further studies are needed to understand the role of transplacental transmission in the epidemiology of these protozoa.

Automated summary

Limited data is available about the presence of Toxoplasma gondii, Neospora spp., and Sarcocystis neurona in equine placental tissues and amniotic fluid. This study found evidence of Neospora spp. DNA in placentas and amniotic fluid of some mares, suggesting a potential transplacental transmission route for Neospora caninum infection.