First report of Neospora caninum-associated bovine abortion in Mashhad area, Iran.
Neospora caninum is an apicomplexan protozoan which causes abortion in cattle worldwide. The present study was designed to assess the importance of bovine neosporosis for causing abortion in Iranian cattle. Infection was primarily diagnosed by polymerase chain reaction (PCR), complemented with histopathology and immunohistochemistry (IHC). One hundred brains of aborted bovine fetuses were collected from Iranian dairy herd between 2003 and 2005 in Mashhad area. N. caninum was detected by PCR in the brains of 13 aborted fetuses. Lesions consistent with N. caninum infection were observed in 12 of fetal brains. Immunohistochemical examination of brain detected N. caninum organisms in three aborted fetuses, and a thick-walled (2 mum) cyst with 50 mum diameter was identified in one of the IHC-positive brain. The results indicated that neosporosis is an important cause of abortion in dairy cattle of Iran.