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The aim of this study was to estimate the occurrence of bovine viral diarrhea virus (BVDV) infection and to assess the population immunity in cattle vaccinated against BVDV in different regions of Kazakhstan. Cattle samples were collected in 12 oblasts (43 districts) of Kazakhstan. A total of 2477 cattle from 114 herds and 21 Bukhara deer (Cervus elaphus bactrianus) were examined by ELISA and conventional RT-PCR. Univariate and multivariate logistic regression analysis was performed to identify risk factors associated with BVDV infection in the country. In total, antibodies against BVDV were found in 79.3% (1965/2477) of all the animals and 92.1% (105/114) of all the herds examined. Seroprevalence in unvaccinated and vaccinated animals was 48.6% (447/920) and 98.7% (1391/1410), respectively. Seroprevalence in deer was 19.1% (4/21). The BVDV RNA was detected in six unvaccinated cattle (0.2%). Sequence analysis of the 5'-untranslated region demonstrated that four of the detected strains belonged to BVDV-1 and two strains to BVDV-2. Regression analysis revealed that age, production type, housing method, farm size, and geographic location were risk factors for BVDV infection in cattle in Kazakhstan. The present data confirm circulation of BVDV-1 and BVDV-2 in Kazakhstan and highlight the need to improve strategies for prevention and control of BVDV infection in the country., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The objective was to compare clinical protection [evaluated through health scoring, endoscopy score of the upper respiratory tract (URT-ES), leukocyte count, viremia, and virus shedding in nasal secretions] following Bovine viral diarrhea virus 2 (BVDV2) and Bovine herpes virus 1 (BHV1) challenge among calves submitted to modified-live virus (MLV) booster vaccination (either intranasal or subcutaneous) concurrent with injectable trace minerals (ITM) or saline. Forty-eight dairy calves received an MLV intranasal (IN) vaccine containing BHV1, BRSV, and BPI 3 V and subcutaneous (SC) ITM (Se, Cu, Zn & Mn; ITM, n = 24) or saline (SAL, n = 24). Ten weeks later, calves received a second dose of ITM, or saline, according to previous groups and were randomly assigned to receive the same IN vaccine [ITM-IN (n = 12), SAL-IN (n = 12)] or a SC MLV vaccine containing BHV1, BRSV, BPI3V, BVDV1 & 2 [ITM-SC (n = 12), SAL-SC (n = 12)]. Additionally, 12 calves did not receive vaccine or treatment and served as a control group (UNVAC, n = 12). Forty-nine days after booster, calves were challenged with BVDV2; and seven days later with BHV1. Health scores indicated disease in UNVAC on days 6, 10 and 12 compared to the vaccinated groups. Unvaccinated calves had the highest URT-ES after BHV1 challenge. Calves that received SC booster had lower URT-ES after BHV1 challenge than UNVAC calves. Calves in ITM-IN had significantly lower URT-ES after BHV1 infection than SAL-IN and UNVAC calves. In conclusion, IN or SC MLV vaccination was similarly effective in protecting calves from BVDV2 + BHV1 challenges (reducing clinical and endoscopy scores, preventing leukopenia, and viremia), compared to unvaccinated calves. Endoscopic evaluation of the URT allowed visualization of the inflammation and damage at multiple depths in the URT caused by a serial BVDV2 + BHV1 challenge. Calves that received SC vaccination had significantly lower URT-ES after BHV1 challenge than the UNVAC calves. Administration of ITM concurrent with IN vaccination was associated with reduced URT inflammation after BVDV2 + BHV1 challenge., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The objective was to evaluate the effects of injectable trace minerals (ITM) concurrent with modified-live virus (MLV) vaccination on protection from bovine viral diarrhea virus (BVDV) infection in dairy calves. In a previous study (Palomares et al., 2016), thirty dairy calves received two doses of a MLV vaccine subcutaneously (SC), concurrently with ITM (n = 15) or saline (n = 15), SC. Five months later, 20 of these calves received ITM (G1, n = 10) or saline (G2, n = 10) according to their previous groups and were challenged intranasally with BVDV2. Five unvaccinated calves were also challenged with BVDV2 (G3). Blood samples were collected on days 0 (BVDV challenge), 3, 5, 6, 7, 8, 9, 11, 14, 18, 21, 32 and 61 for leukocyte count, virus isolation and BVDV serum neutralizing antibodies (SNA). Mild-moderate clinical signs were observed in G3 after BVDV challenge. Group 1 showed lower sum health score and nasal score on d5 and fecal score on d8 compared to G2. Rectal temperature and leukocyte counts were not different between G1 and G2. In contrast, G3 calves had significant leukopenia and lymphopenia from d3 to d7 (P < .05) and higher rectal temperatures on d6 to d8, compared to values on d0 (P < .05). All unvaccinated calves became viremic, while viremia was not detected in G1 or G2. Average daily gain was not different between vaccinated groups, however, only G1 calves had significantly greater (P = .04) ADG compared to non-vaccinated calves during the first 14 days post challenge. Vaccinated calves treated or not with ITM were protected from BVDV2 infection five months post-vaccination., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Bovine viral diarrhea (BVD) is one of the most economically important diseases of cattle. With its very high prevalence, cattle kept on pastures become a source of the virus for the wildlife which, due to their susceptibility, then easily can serve as a source for re-infections of cattle. Therefore, we investigated the BVDV infection in Serbian wild boar and assessed the role of wild boar in BVDV epidemiology including possible spreading to domestic species. This study was based on examination of 50 spleen samples which were collected from wild boars located in Eastern Serbia during the hunting season 2016/2017. BVDV genome was detected in 4 of 50 samples (8%). Phylogenetic analysis based on 5'UTR revealed that BVDV strains from wild boars shared 100% identity. Belonging to the BVDV 1f subgenotype, the most common in cattle, we showed that BVDV infections of wild boar occurred as a result of either direct or indirect contact with domestic animals. Therefore, the occurrence of infectious disease in wildlife emphasizes the need to study the pathogens shared by wildlife and domestic animals by investigating the incidence of pathogens and disease patterns of those populations., (Copyright © 2018 Elsevier Ltd. All rights reserved.)