West Nile virus outbreak detection using syndromic monitoring in horses.

Recent outbreaks of West Nile virus-associated (WNV) diseases, both in the old World and Americas, underline the importance for early warning systems that rapidly identify emerging and re-emerging diseases and thus help in their control. Traditional approaches of disease monitoring become less reliable and increasingly costly when used for rare health-related events, such as WNV outbreaks in southern France. The objective of this work was to discuss methodological issues related to syndromic monitoring of WNV-associated disease in Camargue horses by veterinary practitioners. Tracking cases of equine encephalitis by veterinarians is an example of such syndromic monitoring of an emerging disease. Signs of illness, observed prior diagnostic confirmation, can be of interest because they may provide an early warning for WNV circulation in a given area and allow authorities to take appropriate preventive measures for public health.