Molecular and pathological study of bovine aborted fetuses and placenta from Neospora caninum infected dairy cattle

ABSTRACT

The objective of the study was to evaluate the presence of Neospora caninum organisms in the brain of aborted fetuses and placentas of full-term calves born of seropositive cows. During 2006-2007, 12 brains of aborted calves from Neospora seropositive cattle and 7 placentas from seropositive dams giving birth to full-term calves, from four dairy cattle farms located around Tehran province, Iran were examined by Nested-PCR and histopathology techniques. The Nested-PCR demonstrated that all of 12 aborted fetal brain samples and 5 of 7 placentas were infected by N. caninum. Mild to severe placentitis was observed in 5 placentas. Severe hyperemia and perivascular and perineuronal edema revealed in all fetal brain. In 3 out of 12 brains, scattered foci of hemorrhages, neuropilar necrosis and gliosis were present. In addition, nonpurulent encephalitis with severe lymphohistiocytic perivascular cuffing in one case and a small tissue cyst like Neospora caninum cyst in other calf were observed. Our results confirmed the molecular and histopathologic findings of other studies about Neospora caninum infection and it seems to support the hypothesis that Neospora infection is associated with bovine abortion in Iran