Prevalence of antibodies to specific infectious agents in bovine fetuses from a slaughterhouse in Minnesota

Bovine Parainfluenza-3 Virus Detection Methods and Prevalence in Cattle: A Systematic Review and Meta-Analysis

Bovine parainfluenza-3 virus (BPI3V) is an important respiratory pathogen in cattle, contributing to syndromes in the bovine respiratory disease complex (BRDC). Despite its significance, the understanding of its prevalence remains fragmented, especially within the larger framework of BRDC. This systematic review and meta-analysis aimed to determine the global prevalence of BPI3V in cattle using varied detection methods and to highlight associated risk factors. Of 2187 initially retrieved articles, 71 were selected for analysis, covering 32 countries. Depending on the detection method employed, the meta-analysis revealed significant variations in BPI3V prevalence. In the general cattle population, the highest prevalence was observed using the antibody detection method, with a proportion of 0.64. In contrast, in cattle with BRDC, a prevalence of 0.75 was observed. For the antigen detection method, a prevalence of 0.15 was observed, exclusively in cattle with BRDC. In nucleic acid detection, a prevalence of 0.05 or 0.10 was observed in the general and BRDC cattle populations, respectively. In virus isolation methods, a prevalence of 0.05 or 0.04 was observed in the general and BRDC cattle populations, respectively. These findings highlight the differences in the detection ability of different methods in identifying BPI3V. Other factors, such as country, study year, coinfections, farm size, the presence of respiratory signs, sex, and body weight, may also affect the prevalence. Most studies were anchored within broader BRDC investigations or aimed at detecting other diseases, indicating a potential under-representation of focused BPI3V research. BPI3V plays an important role in BRDC, with its prevalence varying significantly based on the detection methodology. To further understand its unique role within BRDC and pave the way for targeted interventions, there is an evident need for independent, dedicated research on BPI3V.

Intrauterine infection with bovine leukemia virus in pregnant dam with high viral load

Enzootic bovine leukemia is caused by the bovine leukemia virus (BLV). BLV is transmitted vertically or horizontally through the transfer of infected cells via direct contact, through milk, insect bites and contaminated iatrogenic procedures. However, we lacked direct evidence of intrauterine infection. The purpose of this study was to confirm intrauterine BLV infection in two pregnant dams with high viral load by cesarean delivery. BLV was detected in cord and placental blood, and the BLV in the newborns showed 100% nucleotide identity with the BLV-env sequence from the dams. Notably, a newborn was seropositive for BLV but had no colostral antibodies. In this study, we presented a direct evidence of intrauterine BLV transmission in pregnant dam with a high proviral load. These results could aid the development of BLV control measures targeting viral load.

Survey of cell lines in the American Type Culture Collection for bovine viral diarrhea virus

Cell lines originating from cattle, sheep, goat, deer, bison, swine, rabbit, hamster, cat, dog, monkey, human, and mosquito were obtained from the American Type Culture Collection and tested for contamination with bovine viral diarrhea virus (BVDV). Immunocytochemical procedures and polymerase chain reaction (PCR) amplification were used to detect viral antigen or viral RNA in 13 of 41 cell lines. The results of these procedures correlated exactly. Cell lines derived from cattle, sheep, goat, deer, bison, rabbit, and domestic cat were found contaminated with BVDV. Attempts were made to experimentally infect 14 swine, rabbit, hamster, cat, dog, monkey, and human cell lines that had been found free of virus. All swine cell lines, and most rabbit and cat cell lines, became infected with BVDV. Hamster, human, dog, and certain rabbit and cat cells were refractory to BVDV infection. Experimental infection of monkey cells produced variable results.

Methods for detection and frequency of contamination of fetal calf serum with bovine viral diarrhea virus and antibodies against bovine viral diarrhea virus

Methods used by the National Animal Disease Center to test fetal calf serum for contamination with bovine viral diarrhea virus (BVDV) and antibodies against BVDV are described. Using those methods, virus was isolated from 332 of 1,608 (20.6%) lots of raw fetal calf serum obtained specifically for the Center and 93 of 190 (49%) lots of commercially available fetal calf serum. Virus neutralization and immunoperoxidase staining tests were used to detect antibodies against BVDV in 224 of the 1,608 (13.9%) lots of raw fetal calf serum. Both BVDV and antibodies against BVDV were detected in 50 lots of raw serum. The molecular specificity of antibodies against BVDV was determined by radioimmunoprecipitation. Lots of fetal calf serum that contained BVDV-specific antibodies that did not neutralize virus were identified.