Simultaneous Infection of Bovine Aborted Fetuses by Infectious Bovine Rhinotracheitis and Neospora caninum in a Dairy Farm around Tehran, Iran

Background: Infectious bovine rhinotracheitis (IBR) is a predominant viral abortifacient agent, and Neospora caninum has been documented as a primary etiological agent of reproductive losses in dairy herds. The present study aimed to investigate the concurrent infection of bovine fetuses with IBR and N. caninum, emphasizing the critical need for implementing control measures. Methods: A total of ۲۳ blood samples, ۲۳ placentas, ۲۳ vaginal secretions, and ۷ fetuses from aborted cattle, were collected for the identification of N. caninum and IBRV. Real-time PCR was developed for the detection of N. caninum and herpesvirus ۱ (BoHV-۱). The presence of N. caninum and IBRV specific antibodies was assessed using commercially available ELISA kits. Results: Serological analysis revealed a higher prevalence of IBRV infection compared to N. caninum, whereas aborted fetuses demonstrated greater frequency of N. caninum infection. ELISA results indicated that ۶۰.۹% and ۴۳.۵% of cattle sera tested positive for antibodies against IBRV and N. caninum, respectively. IBRV was detected in ۳۴.۸% of the fetuses, while N. caninum infection was identified in ۴۳.۵%. Concurrent infection with both pathogens was observed in ۲۶.۱% of the fetuses, and ۴.۳% of placental and vaginal discharge samples tested positive for both agents. All positive fetuses and the infected placental sample originated from seropositive cattle. Conclusion: In conclusion, cattle co-infection with IBR and N. caninum increases the rate of abortion rather than infection with each pathogen alone. This study highlights the important need for enforcement of control measures for neosporosis & IBR infection in cattle, which requires vaccination and biosecurity techniques. Implementation of comprehensive hygienic measures is essential which should include rigorous environmental disinfection, isolation of suspected cases, control of stray dogs (the definitive host of Neospora spp.), and proper disposal of reproductive tissues to effectively limit disease transmission.

کلیدواژه ها:

Abortion ، Cattle ، Dog ، Infectious bovine rhinotracheitis ، Neospora caninum