Detection of bovine viral diarrhea virus and bovine herpes virus type 1 in cattle with and without endometritis

This study aimed to investigate the potential presence of bovine herpes virus type 1 (BHV-1) and bovine viral diarrhea virus (BVDV) in cattle uteri that did not display any clinical and macroscopic signs of infection. Virus detection involved polymerase chain reaction (PCR) test, double immunohistochemistry (IHC), and double immunofluorescence (IF). One hundred cornu uterus samples were collected from cattle aged 1 year and older. The BVDV was detected by PCR or by double IHC/IF in the collected samples from slaughterhouses in Kayseri city (Central Anatolia, Türkiye) from 2021 - 2022. By contrast, BHV-1 was detected by PCR and double IHC/IF at a rate of 16.00% and 21.00%, respectively. In the IHC and IF detection, BHV-1 was detected in endometrial epithelial cells and in some mononuclear cells in the lamina propria, periglandular areas and myometrium. Although no macroscopic lesion was found in the BHV-1-positive samples (n = 21), histopathological detection showed that two had acute endometritis, eight had subacute endometritis, eight had chronic endometritis and the three others showed no signs of endometritis. This prevalence study demonstrated for the first time that even while BVDV could not be detected in the samples, BHV-1 posed a critical potential reproductive risk in pregnant animals, as it can specifically cause abortions when it resides in cattle uteri that do not show clinical or macroscopic and even microscopic signs of infection. Additionally, this study was the first to combine PCR and double IHC/IF for BHV-1 and BVDV detection in cattle uteri.