Can horses be clinically screened for West Nile Fever?

In Europe, the frequency of West Nile Fever (WNF) outbreaks in horses and/or human beings is on the increase, especially in mid-eastern and southern Europe (Dauphin and others 2004, Rabel and others 2011). However, in several western European countries no activity of the virus has been detected so far, for example, in The Netherlands (Rockx and others 2006), Belgium and the UK (Morgan 2006)). However, considering the presence of migratory birds and suitable vectors in those countries, and the reports of changing epidemiology of the virus (Petersen and Marfin 2005, Blitvich 2008), the West Nile virus (WNV) is a genuine threat. Horses are considered good sentinels for WNV infection surveillance (Petersen and Marfin 2005) by the use of syndromic surveillance followed by laboratory confirmation. Syndromic surveillance aims at early identification of disease clusters before laboratory confirmation, thereby reducing morbidity and mortality (Leblond and others 2007). Clinical signs of WNF in horses are, however, difficult to distinguish from those of other neurological diseases (Leblond and others 2007, Porter and others 2011). The aim of this study was to identify clinical variables that could be indicators for WNF in horses, which will be attempted …