West Nile Fever is a zoonotic disease caused by a mosquito-borne flavivirus, WNV. By its clinical sensitivity to the disease, the horse is a useful sentinel of infection. Because of the virus’ low-level, short-term viraemia in horses, the primary tools used to diagnose WNV are serological tests. Inter-laboratory proficiency tests (ILPTs) were held in 2010 and 2013 to evaluate WNV serological diagnostic tools suited for the European network of National Reference Laboratories (NRLs) for equine diseases. These ILPTs were designed to evaluate the laboratories’ and methods’ performances in detecting WNV infection in horses through serology. The detection of WNV immunoglobulin G (IgG) antibodies by ELISA is widely used in Europe, with 17 NRLs in 2010 and 20 NRLs in 2013 using IgG WNV assays. Thanks to the development of new commercial IgM capture kits, WNV IgM capture ELISAs were rapidly implemented in NRLs between 2010 (4 NRLs) and 2013 (13 NRLs). The use of kits allowed the quick standardisation of WNV IgG and IgM detection assays in NRLs with more than 95% (20/21) and 100% (13/13) of satisfactory results respectively in 2013. Conversely, virus neutralisation tests (VNTs) were implemented in 33% (7/21) of NRLs in 2013 and their low sensitivity was evidenced in 29% (2/7) of NRLs during this ILPT. A comparison of serological diagnostic methods highlighted the higher sensitivity of IgG ELISAs compared to WNV VNTs. They also revealed that the low specificity of IgG ELISA kits meant that it could detect animals infected with other flaviviruses. In contrast VNT and IgM ELISA assays were highly specific and did not detect antibodies against related flaviviruses. These results argue in favour of the need for and development of new, specific serological diagnostic assays that could be easily transferred to partner laboratories.

西尼罗河热是一种由蚊子传播的黄病毒WNV引起的人畜共患疾病。由于对疾病的临床敏感性，马是有用的感染前哨。由于该病毒在马匹中低水平，短期病毒血症，因此用于诊断WNV的主要工具是血清学检测。2010年和2013年进行了实验室间能力验证（ILPT），以评估适用于欧洲马匹国家参考实验室（NRL）网络的WNV血清学诊断工具。这些ILPT旨在评估实验室和方法通过血清学检测马匹WNV感染的性能。通过ELISA检测WNV免疫球蛋白G（IgG）抗体在欧洲已广泛使用，2010年使用IgG WNV分析检测到17种NRL，2013年检测到20种NRL。得益于新的商用IgM捕获套件的开发，在2010年（4个NRL）和2013年（13个NRL）之间的NRL中快速实施了WNV IgM捕获ELISA。使用试剂盒可快速标准化NRL中的WNV IgG和IgM检测测定，在2013年分别获得超过95％（20/21）和100％（13/13）的满意结果。相反，病毒中和测试（VNT） 2013年，在33％（7/21）的NRL中实施了这些工具，而在本次ILPT期间，有29％（2/7）的NRL证明了它们的低敏感性。血清学诊断方法的比较表明，与WNV VNT相比，IgG ELISA的敏感性更高。他们还发现，IgG ELISA试剂盒的低特异性意味着它可以检测出感染了其他黄病毒的动物。相反，VNT和IgM ELISA分析具有高度特异性，并且未检测到针对相关黄病毒的抗体。