The Northern Ireland Control Programmes for Infectious Cattle Diseases Not Regulated by the EU

Genotypic analysis of a localised hotspot of Pestivirus A (BVDV-1) infections in Northern Ireland

BACKGROUND

Bovine viral diarrhoea (BVD) is caused by Pestivirus A and Pestivirus B. Northern Ireland (NI) embarked on a compulsory BVD eradication scheme in 2016, which continues to this day, so an understanding of the composition of the pestivirus genotypes in the cattle population of NI is required.

METHODS

This molecular epidemiology study employed 5' untranslated region (5'UTR) genetic sequencing to examine the pestivirus genotypes circulating in samples taken from a hotspot of BVD outbreaks in the Enniskillen area in 2019.

RESULTS

Bovine viral diarrhoea virus (BVDV)-1e (Pestivirus A) was detected for the first time in Northern Ireland, and at a high frequency, in an infection hotspot in Enniskillen in 2019. There was no evidence of infection with BVDV-2 (Pestivirus B), Border disease virus (pestivirus D) or HoBi-like virus/BVDV-3 (pestivirus H).

LIMITATIONS

Only 5'UTR sequencing was used, so supplementary sequencing, along with phylogenetic trees that include all BVDV-1 genotype reference strains, would improve accuracy. Examination of farm locations and animal movement/trade is also required.

CONCLUSIONS

Genotype BVDV-1e was found for the first time in Northern Ireland, indicating an increase in the genetic diversity of BVDV-1, which could have implications for vaccine design and highlights the need for continued pestivirus genotypic surveillance.

Prevalence of bovine viral diarrhea virus in cattle between 2010 and 2021: A global systematic review and meta-analysis

Background

Bovine viral diarrhea is one of the diseases that cause huge economic losses in animal husbandry. Many countries or regions have successively introduced eradication plans, but BVDV still has a high prevalence in the world. This meta-analysis aims to investigate the prevalence and risk factors of BVDV in the world in recent 10 years, and is expected to provide some reference and theoretical basis for BVDV control plans in different regions.

Method

Relevant articles published from 2010 to 2021 were mainly retrieved from NCBI, ScienceDirect, Chongqing VIP, Chinese web of knowledge (CNKI), web of science and Wanfang databases.

Results

128 data were used to analyze the prevalence of BVDV from 2010 to 2021. BVDV antigen prevalence rate is 15.74% (95% CI: 11.35-20.68), antibody prevalence rate is 42.77% (95% CI: 37.01-48.63). In the two databases of antigen and antibody, regions, sampling time, samples, detection methods, species, health status, age, sex, breeding mode, and seasonal subgroups were discussed and analyzed, respectively. In the antigen database, the prevalence of dairy cows in the breed subgroup, ELISA in the detection method subgroup, ear tissue in the sample subgroup, and extensive breeding in the breeding mode were the lowest, with significant differences. In the antibody database, the prevalence rate of dairy cows in the breed subgroup and intensive farming was the highest, with a significant difference. The subgroups in the remaining two databases were not significantly different.

Conclusion

This meta-analysis determined the prevalence of BVDV in global cattle herds from 2010 to 2021. The prevalence of BVDV varies from region to region, and the situation is still not optimistic. In daily feeding, we should pay attention to the rigorous and comprehensive management to minimize the spread of virus. The government should enforce BVDV prevention and control, implement control or eradication policies according to local conditions, and adjust the policies in time.

BVD seroprevalence in the Irish cattle population as the national BVD programme progresses toward eradication

BACKGROUND

Bovine Viral Diarrhoea Virus (BVDV) infection remains endemic in many countries worldwide. Ireland, in common with several other European counties, commenced an BVDV eradication programme in the last decade, Managing eradication programmes requires careful monitoring of diseases prevalence and understanding factors associated with disease exposure to ensure eradication programmes remain evidence based and tailored to the evolving epidemiological situation.

METHODS

In this study, we explore the seroprevalence of BVDV exposure over a four-year period (2017 to 2020) in Ireland from a cohort of animals (n = 6,449) under 30 months of age sampled at slaughter, who were born subsequent to the commencement of a compulsory national eradication programme. Temporal trends and risk factor analysis were undertaken using multilevel logit regression models.

RESULTS

There was a declining temporal trend in seroprevalence over the sample years of the study, and risk varied at both county- and herd-levels. The unadjusted marginal animal-level seroprevalence reduced from 9.1% in 2017 (95%; CI: 7.2-10.9) to 3.9% in 2020 (95%; CI: 3.2-4.6). The final model suggested that seropositivity in study cattle was strongly related with the presence of a PI animal in the herd during the year of the animal's birth, and to a lesser extent the status of the herd from which the animal was slaughtered. The risk of seroconversion increased significantly with increasing size of the herd of slaughter, in females relative to males, and in dairy relative to suckler herds.

CONCLUSIONS

This study has shown that the BVDV serostatus of cattle at slaughter is correlated to the BVD infection history of the herd into which the animal was born and the herd from which it was slaughtered. Herd location, increased herd size and dairy production were associated with increased probability of serconversion. These findings will be used to inform the targeting of surveillance strategies once BVDV freedom has been achieved.