Neospora caninum isolation from beef catte: immunodiagnostic and PCR studies

CAMPERO L.M.; DELLARUPE A.; GUAL I.; MORÉ G.; RAMBEAUD M.; MORRELL E.; MOORE D.P.; VENTURINI M.C.

Gramado

Congreso; XVIII CONGRESSO BRASILEIRO DE PARASITOLOGIA VETERINÁRIA; 2014

Bovine neosporosis is a parasitic disease caused by the protozoan Nesopora caninum, manifested mainly by abortion between 4- 8 months of gestation that causes significant economic losses in beef and dairy cattle. The aims of this work were to obtain isolates of N. caninum from beef herds in Argentina and to confirm diagnosis by PCR analysis. A 10 year old Angus cow with 6 months of gestation was necropsied. Central nervous system (CNS) from the mother and fetus and placenta were submitted for histopathological (HP), immunohistochemical (IHC) and polymerase chain reaction (PCR) studies, and indirect fluorescent antibody test (IFAT) was also performed. The digested CNS was inoculated in gamma knockout mice for isolation, and characterization by HP, IHC and IFAT were performed in infected mice. Histopathological results in the dam, placenta and fetus revealed lesions compatible with N. caninum (miocarditis, meningoencephalitis and hemorrhage, lymphoplasmahistiocytic placentitis). Clusters of tachyzoites were detected in the placenta by IHQ. PCR results were positive for the placenta and the SNC of the fetus. Serum from the dam and fetal liquid had IFAT titers of 1:3200. Twenty five days postinoculation (dpi) mice were bled and tested by IFAT. Three of four mice that were inoculated with SNC form the fetus were serologically positive, and sacrificed at day 26 dpi. Brains from seropositive mice were used for successive in vivo passages and peritoneal washings were used to infect cell culture. Tachyzoites were detected in the flasks 1 week post infection. HP mice results revealed mononuclear and neutrophil infiltrate in liver, heart and lungs. Mice presented positive IHC staining in lungs and heart. Infected mice tissues (CNS, heart, lungs, liver and peritoneal fluid) and cell culture derived tachyzoites were positive by PCR. Mulitilocusmicrosatellite analysis is currently underway to genetically characterize this new bovine isolate. Further bioassays will be performed to characterize this new isolate.