Key result
In vaccinated cattle herds experiencing vaccination failure, overall seroprevalence was 83.3% by virus neutralization test, but 41.4% of positive samples lacked a predominant titer against a specific BVDV subtype.
Why the study?
The study aimed to compare the serological response in cattle herds where new persistently infected calves were identified without prior removal of persistently infected animals or despite their removal after introducing whole herd vaccination against BVDV.
Observational (n=133)
Yes
Vaccination with BVDV-1a may fail to protect cattle fetuses from persistent infection when exposed to heterologous field strains like BVDV-1b and BVDV-1d.
Answers are grounded in this paper and cite their sources.
BVDV-1a vaccines may not prevent persistent infection by heterologous strains; leaves open the need for updated multivalent formulations in endemic herds.
Vaccination against bovine viral diarrhea (BVD) is one of the key elements to protect cattle herds from this economically important disorder. Bovine viral diarrhea virus (BVDV) is a pestivirus infecting animals at all ages with significant impact on reproductive, digestive, and respiratory systems. Financial burden caused by this pathogen prompts many farmers to introduce vaccination as the control and prophylactic measure especially when persistently infected (PI) individuals, being the main source of the virus in the herd, are removed after test-and-cull approach. The aim of the study was to compare the serological response in cattle herds where new PI calves were identified without prior removal of PI animals or despite their removal and after the introduction of whole herd vaccination against BVDV infection. Overall seroprevalence in 5 vaccinated herds was 91.7 and 83.3% using ELISA and virus neutralization test, respectively. Despite high titers for both vaccine and field strains of BVDV in analyzed herds the analysis of comparative strength of neutralization indicated that 41.4% of positive samples did not have a predominant titer against one specific subtype of BVDV. In 3 herds BVDV-1b subtype was identified while in 2 others it was BVDV-1d, while the vaccine used was based on BVDV-1a which was never identified in Poland so far. To increase the success of the BVDV eradication program, a careful approach is suggested when planning herd vaccination. Comparison of existing field strains and their similarity with vaccine strains at antigenic and genetic levels can be a useful approach to increase the effectiveness of vaccination and efficient protection of fetuses from persistent infection.
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Antos et al. (2021) conducted an observational in Bovine viral diarrhea (BVD) vaccination failure (n=133). Whole herd vaccination against BVDV (BVDV-1a strain) was evaluated on Overall seroprevalence using virus neutralization test (VNT). In vaccinated cattle herds experiencing vaccination failure, overall seroprevalence was 83.3% by virus neutralization test, but 41.4% of positive samples lacked a predominant titer against a specific BVDV subtype.
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