Iain Wanless / Flickr. Dying crows were one early sign of West Nile Virus entering North America
In 1999, crows began dropping dead in the United States. A crow here, a crow there – nobody thought much of it at the time, says Joshua Dein, a veterinary scientist working with the University of Wisconsin-Madison. But this was the precursor to outbreaks of the West Nile Virus in North America. Since scientists knew the virus infected crows at a near 100% mortality rate, Dein says it is possible public health officials could have been forewarned about the oncoming virus had someone been monitoring the crow situation.
But this is a goal easier said than done. Early detection of disease events that affect wildlife is often difficult to achieve because sometimes the evidence is diffuse and hard to collect. “When you have hundred dead ducks in one place that usually gets attention. ...
