Retrospective serological survey for influenza in horses from Brazil

Daly, J. M.; Megid, J.; Langoni, H.; de Nardi J�nior, G.; Ribeiro, M. G.

Abstract

Equine influenza (EI) virus is one of the most economically important pathogens of respiratory diseases of horses worldwide. Despite availability of vaccines for control of EI, the highly contagious nature and variability properties of the virus mean global outbreaks occur. Thus, continuous surveillance programs, including seroprevalence studies of disease in different countries, may contribute to better control of the disease. In this study, the seroprevalence of equine influenza in 850 horses from Brazil was investigated. The serodiagnosis was based on the single radial hemolysis (SRH) assay using influenza A/equine/Richmond/1/2007 (H3N8) antigen. Antibodies against A/equine/Richmond/1/07 (H3N8) were detected in 44.7% (380/850, 95% CI: 41.4–48.1%) of horses. Seroprevalence was significantly lower (p = 0.001) in younger animals (< 5years, 38.6%) than in “adult” animals (5–14years, 52.1%). There was also a significant relationship between the year of sampling and seroprevalence (p < 0.0005). The mean SRH antibody value was 42.0mm2 (range 4–238.9mm2), with the majority of horses (95.3%) having an SRH value ≤ 150mm2, which is considered an insufficient level for protection of equine hosts against influenza infections and potential virus shedding. These findings indicate the need to reinforce preventive/control measures against equine influenza in Brazil.

Citation

Daly, J. M., Megid, J., Langoni, H., de Nardi Júnior, G., & Ribeiro, M. G. (2021). Retrospective serological survey for influenza in horses from Brazil. Brazilian Journal of Microbiology, 52(1), 461-466. https://doi.org/10.1007/s42770-020-00398-8

• Journal Article Type: Article
• Acceptance Date: Oct 26, 2020
• Online Publication Date: Nov 11, 2020
• Publication Date: 2021-03
• Deposit Date: Oct 28, 2020
• Publicly Available Date: Nov 12, 2021
• Journal: Brazilian Journal of Microbiology
• Electronic ISSN: 1678-4405
• Peer Reviewed: Peer Reviewed
• Volume: 52
• Issue: 1
• Pages: 461-466
• DOI: https://doi.org/10.1007/s42770-020-00398-8
• Keywords: Horses; influenza virus H3N8; seroprevalence; serodiagnosis
• Public URL: https://nottingham-repository.worktribe.com/output/4997001
• Publisher URL: https://link.springer.com/article/10.1007/s42770-020-00398-8
• Additional Information: This is a post-peer-review, pre-copyedit version of an article published in Brazilian Journal of Microbiology. The final authenticated version is available online at: https://doi.org/10.1007/s42770-020-00398-8