Rocheleau Jean-Philippe, Arsenault Julie, Lindsay L Robbin, DiBernardo Antonia, Kulkarni Manisha A, Côté Nathalie, Michel Pascal
1 Groupe de recherche en épidémiologie des zoonoses et santé publique, Faculté de médecine vétérinaire, Université de Montréal , Saint-Hyacinthe, Québec, Canada .
Vector Borne Zoonotic Dis. 2013 Oct;13(10):712-8. doi: 10.1089/vbz.2012.1242. Epub 2013 Aug 6.
Eastern equine encephalitis virus (EEEV) is a highly pathogenic arbovirus that infects humans, horses, and other animals. There has been a significant increase in EEEV activity in southeastern Canada since 2008. Few data are available regarding nonlethal EEEV infections in mammals, and consequently the distribution and pathogenicity spectrum of EEEV infections in these hosts is poorly understood. This cross-sectional study focuses on the evaluation of viral activity in southern Quebec's horses by seroprevalence estimation. A total of 196 horses, 18 months and older, which had never been vaccinated against EEEV and have never traveled outside Canada, were sampled from 92 barns distributed throughout three administrative regions of southern Quebec. Blood samples were taken from each horse and titrated for EEEV antibodies by plaque reduction neutralization test (PRNT). Equine population vaccination coverage was estimated by surveying horse owners and equine practitioners. PRNT results revealed an EEEV seroprevalence up to 8.7%, with 95% confidence limits ranging from 4.4% to 13.0%. Vaccination coverage was estimated to be at least 79%. Our study reveals for the first time in Canada a measure of EEEV seroprevalence in horses. High seroprevalence in unvaccinated animals challenges the perception that EEEV is a highly lethal pathogen in horses. Monitoring high-risk vector-borne infections such as EEEV in animal populations can be an important element of a public health surveillance strategy, population risk assessment and early detection of epidemics.
东部马脑炎病毒（EEEV）是一种高致病性虫媒病毒，可感染人类、马和其他动物。自2008年以来，加拿大东南部的EEEV活动显著增加。关于哺乳动物非致死性EEEV感染的数据很少，因此对这些宿主中EEEV感染的分布和致病性谱了解甚少。这项横断面研究的重点是通过血清流行率估计来评估魁北克南部马匹的病毒活性。从魁北克南部三个行政区分布的92个马厩中抽取了总共196匹18个月及以上、从未接种过EEEV疫苗且从未出过加拿大的马匹。从每匹马采集血样，并通过蚀斑减少中和试验（PRNT）对EEEV抗体进行滴定。通过对马主和马医进行调查来估计马群的疫苗接种覆盖率。PRNT结果显示EEEV血清流行率高达8.7%，95%置信区间为4.4%至13.0%。疫苗接种覆盖率估计至少为79%。我们的研究首次在加拿大揭示了马匹中EEEV血清流行率的情况。未接种疫苗动物的高血清流行率挑战了EEEV在马匹中是一种高致死性病原体的观念。监测动物群体中诸如EEEV等高危媒介传播感染可能是公共卫生监测策略、群体风险评估和疫情早期检测的重要组成部分。
