Detection and prevalence of bovine viral diarrhea virus in ovarian follicular fluid: A potential risk for in vitro embryo production

Abstract

Bovine Viral Diarrhea Virus (BVDV) and anti-BVDV antibodies have been detected in ovarian follicular fluid of infected cows. The aim of this study was to assess both the frequency of BVDV detection and the prevalence of anti-BVDV antibodies in pooled follicular fluid obtained from slaughterhouse ovaries for in vitro embryo production. Additionally, we sought to determine whether specific antibodies present in these samples are able to neutralize different BVDV strains. BVDV RNA was detected by using reverse transcription polymerase chain reaction (RT-PCR) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), while viral viability was evaluated by using viral isolation (VI). Antibody titers against different BVDV strains (reference strain NADL-1a Vs145; field strain 13/558-1a; field strains 10/49-1b) were determined through viral neutralization (VN) assays. A total of 60 pooled follicular fluid samples from slaughterhouse ovaries were analyzed over a period of 19 months. Results showed that 45 % (27 out of 60) of the samples tested positive for BVDV RNA via RT-PCR and RT-qPCR, although no samples yielded viable virus through the VI technique. The seroprevalence of anti-BVDV antibodies was 98 % (59 out of 60), with antibody titers sufficient (1:136 and 1:268) to neutralize the field strains tested. These findings indicate a high prevalence of BVDV RNA and extensive seroprevalence of anti-BVDV antibodies in pooled follicular fluid samples. The high antibody levels may compromise the sensitivity of VI, likely due to a viral inhibitory effect. Such inhibition could also influence the dynamics of infection throughout the in vitro embryo production process.