Molecular Confirmation of Neospora caninum as the Etiological Agent of Abortion in a Dairy Cattle Herd in Qazvin Province, Iran

Abstract

Background: Neospora caninum, a cyst-producing parasite is identified as one of the main causes of reproductive failure in cattle worldwide. Neosporosis results in increased rates of abortion and reduced milk production, leading to financial losses. This study aimed to identify Neospora caninum infection in aborted cattle and their fetuses, at a dairy cattle farm, focusing on the involvement of stray dogs in spreading the agent within the herd.

Methods: During a three-month investigation in 2023, twenty-one cattle in a farm in Qazvin Province, Iran, showed abortion at 2, 4, 5, and 7 months of pregnancy, while stray dogs had free access to various sections of the farm. Serum samples were collected from each of the aborted dams. Seven aborted fetuses, along with two placentas, were also transported to the laboratory in frozen ice packs for testing for N. caninum. The fetal and placenta samples underwent examination through molecular assessment.

Results: Anti-Neospora antibodies were detected in the sera of 7 out of 21 cattle, corresponding to a seroprevalence rate of 33.3%. Among these, three out of seven aborted fetuses tested positive for Neospora via real-time PCR, all of derived from seropositive cattle. Neospora caninum was not detected in any of the placental samples examined.

Conclusion: N. caninum significantly influences the occurrence of abortions in dairy cattle. Although transmission of infection from an infected dam to a fetus is the most prominent route of the disease transmission, the proximity of stray dogs to cattle herds plays a key role in increasing number of infected cases.