Seroprevalence of West Nile virus in feral horses on Sheldon National Wildlife Refuge, Nevada, United States 2004-2006, 2008 and 2009

The authors screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004-2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004-2006 were negative. In 2008 and 2009, the authors found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for antibody against SLEV. Being unvaccinated, feral horses can be useful for WNV surveillance.本研究团队于2004-2006年、2008年及2009年间，在美国内华达州谢尔顿国家野生动物保护区内，对1397匹野生马（Equus caballus）开展黄病毒（flavivirus）特异性免疫球蛋白M（IgM）与免疫球蛋白G（IgG）抗体筛查。针对黄病毒抗体筛查呈阳性的血清样本，研究团队进一步检测其针对西尼罗病毒（West Nile virus, WNV）和圣路易斯脑炎病毒（St. Louis encephalitis virus, SLEV）的中和抗体。2004年仅1匹马的西尼罗病毒抗体呈阳性，2004-2006年间其余受检样本均为阴性。2008至2009年，研究团队发现野生马的西尼罗病毒血清阳性率随年龄增长而升高，但整体血清阳性率从2008年的19%降至2009年的7.2%。本次研究未检测到圣路易斯脑炎病毒抗体阳性的马匹。由于未接种相关疫苗，野生马可作为西尼罗病毒监测的有效研究对象。