 Terry Yates, a professor at the University of New Mexico, joined an interdisciplinary research team charged with finding the source of the mysterious illness by the National Science Foundation.Yates, along with his research assistant, Robert Parmenter, isolated the source of the illness, which became known as the hantavirus, by using animal specimens which he had collected throughout the American Southwest.Yates found that the hantavirus was carried by the deer mouse, a species which had a higher than usual population in early 1993 due to unusually wet weather in the region.