Study on outbreak of Neospora caninum-associated abortion in dairy cows in Tabriz (Northwest Iran) by serological, molecular and histopathologic methods

Objective: To determine Neospora, caninum (N. caninum) as a cause of bovine abortion in dairy cows by ELISA, PCR and Pathological methods in Tabriz, Northwest of Iran. Methods: For study of outbreak of neosporosis, blood samples were collected from 76 Holstein aborted dairy cows in Tabriz (Northwest Iran. Antibodies to N. caninum, were assayed by using a commercially ELISA kit (IDEXX, USA). IgG against N. caninum were found in 14 (18.4%) cases. Aborted fetuses of these seropositive clams were proposed for histopathological and molecular investigations. Brains, spinal cords and placentas of the fetuses were fixed in 10% buffered formalin for histopathology. Also 5-10 g of brain tissue was sampled for DNA extraction. In 6 out of 14 (42.8%) fetuses, brain tissue was positive in PCR. All dams of these fetuses were serologically seropositive in ELISA test. Results: Histopathologically, the lesions consistent with N. caninum were observed in brains, spinal cords and placenta of all fetuses. Lesions in CNS included severe congestion, perivascular and perineuronal edema, status spongiosis, perivascular cuffing, focal gliosis, nourophagy and focal necrosis. There were some Neospora like cysts in brain. In placentas, severe congestion, perivascular infiltration of mononuclear cells, vascular thrombosis, focal placentitis and necrotic foci in cotyledons were noticed. Conclusions: The results of present study tweed the results of similar studies about serological, histopathological and molecular results of other studies about neosporosis and it seems to support the outbreak of N. caninum associated abortion in dairy cows in Tabriz (Northwest Iran).