Background: Bovine viral diarrhea virus (BVDV) is one of the most important economic diseases affecting many livestock-producing countries. The disease can lead to embryo resorption, abortion, and the birth of weak calves. BVDV control strategies include vaccination and implementation of effective biosecurity.
Objectives: The current research with the aim of highlighting the biosecurity principles, investigated the presence of the virus in cases of abortion in a vaccinated dairy herd using molecular and histopathological methods.
Methods: A total of 23 swab samples from abortion secretions, 7 aborted fetuses, and parenchymatous tissues from 2 slaughtered calves with neurological symptoms were sent to the laboratory for the detection of BVDV using real-time polymerase chain reaction (real-time PCR and histopathological examination.
Results: Four aborted fetuses (57.14%) and 15 swab samples (65.22%) were detected as positive for BVDV by the molecular test. The two slaughtered calves with neurological symptoms, including exophthalmos, ataxia and hydranencephaly were both BVDV positive. The positive samples in the molecular test, showed mild to severe changes related to BVDV infection except for the heart samples. The specific findings included lymphoid tissue depletion in the spleen, multifocal gliosis in the cerebrum, vesicular degeneration in the hepatocytes, multifocal purulent interstitial nephritis, interstitial pneumonia, and multifocal necrotic cryptitis in the histopathological examination.
Conclusion: The results of the present research indicate that vaccination alone is not enough to control BVD and strict adherence to biosecurity protocols is as important as vaccination in the prevention and control of the disease.