MADISON A little information can go a surprisingly long way when it comes to understanding rodent-borne infectious disease, as shown by a new study led by John Orrock from the University of Wisconsin-Madison.
The researchers studied wild deer mouse populations on the Channel Islands off the southern coast of California, which carry a variant of hantavirus called Sin Nombre virus. In their study appearing in the May issue of the journal American Naturalist, they show that just three ecological factors rainfall, predator diversity, and island size and shape can account for nearly all of the differences in infection rates among the eight islands.
The study also provides some of the first evidence to support a recent hypothesis that predators play an important ecological role in regulating disease sometimes known as the "predators are good for your health" hypothesis.
In humans, Sin Nombre virus causes Hantavirus Pulmonary Syndrome, a virulent and often fatal disease. An outbreak of Sin Nombre virus in 1993 in the Four Corners area of the U.S. Southwest killed several people and brought national attention to the disease. Learning what factors control the prevalence and spread of viruses like Sin Nombre within host populations is crucial for understanding the risks of animal-borne diseases.
"The ecological underpinnings of disease prevalence, its dynamics in natural populations, and its transmission from animals to humans are important links that are still being deciphered," says Orrock, an assistant professor of zoology at UW-Madison.
Mouse populations on the Channel Islands have some of the highest rates of Sin Nombre virus ever measured. That, coupled with the isolation and well-defined food webs of the islands, makes them a good system to study what ecological factors affect the presence of the virus.
"The prevalence of disease was predictably found to be a function of ecological variables that humans can measure,"
|Contact: John Orrock|
University of Wisconsin-Madison