School of Veterinary Medicine and Science, University of Nottingham, Nottingham, UK.
Infectious Diseases of Domestic Animals, Department of Animal Production and Preventive Veterinary Medicine, School of Veterinary Medicine and Animal Science, São Paulo State University-UNESP, Botucatu, SP, 18618-681, Brazil.
Braz J Microbiol. 2021 Mar;52(1):461-466. doi: 10.1007/s42770-020-00398-8. Epub 2020 Nov 11.
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 (< 5 years, 38.6%) than in "adult" animals (5-14 years, 52.1%). There was also a significant relationship between the year of sampling and seroprevalence (p < 0.0005). The mean SRH antibody value was 42.0 mm (range 4-238.9 mm), with the majority of horses (95.3%) having an SRH value ≤ 150 mm, 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.
马流感（EI）病毒是世界范围内马呼吸系统疾病最重要的经济病原体之一。尽管有疫苗可用于控制 EI，但该病毒具有高度传染性和变异性，这意味着全球仍会爆发疫情。因此，包括对不同国家疾病进行血清学监测的持续监测计划，可能有助于更好地控制该病。在本研究中，对来自巴西的 850 匹马的马流感血清流行率进行了调查。血清学诊断基于使用 A/equine/Richmond/1/2007（H3N8）抗原的单径向溶血（SRH）测定。在 850 匹马中，有 44.7%（380/850，95%CI：41.4-48.1%）的马检测到针对 A/equine/Richmond/1/07（H3N8）的抗体。在较年幼的动物（<5 岁，38.6%）中，血清流行率显著低于“成年”动物（5-14 岁，52.1%）（p=0.001）。采样年份与血清流行率之间也存在显著关系（p<0.0005）。SRH 抗体的平均值为 42.0mm（范围 4-238.9mm），大多数马（95.3%）的 SRH 值≤150mm，这被认为是不足以保护马宿主免受流感感染和潜在病毒脱落的水平。这些发现表明，巴西需要加强针对马流感的预防/控制措施。
