Navigation Links
Precipitation, predators may be key in ecological regulation of infectious disease

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," Orrock says. "What this illustrates is that if you know just a few things, you can have a reasonable shot of predicting the disease prevalence."

Working with Brian Allan from the University of Illinois at Urbana-Champaign and Charles Drost from the U.S. Geological Survey's Southwest Biological Science Center, Orrock mined an existing dataset, collected on the Channel Islands shortly after the Four Corners outbreak, to look for relationships between biological and physical island characteristics and the prevalence of Sin Nombre on each of the eight islands.

The researchers found that 79 percent of the variation in disease prevalence among the islands could be explained by a single factor average annual precipitation. Adding in the physical characteristics of the islands and the number of predators accounted for 98 percent of the variation. Higher infection rates among Channel Island deer mice were strongly associated with more precipitation, larger island area and fewer predator species.

The strong effect of precipitation levels highlights potential links between changing climate regimes and human health. The results also suggest that more diverse predator populations could help keep animal-borne diseases in check an important lesson as top predators like wolves and bears increasingly disappear from ecosystems due to habitat loss and conflicts with humans.

The authors note that future studies should use experimental methods and examine larger systems to evaluate the generality of the observed patterns. Nonetheless, the strength of the associations they found on the Channel Islands is striking.

"What's shocking about these data is how tight the relationship is," Orrock says. "Rarely in ecology do you find that one variable will explain 79 percent of the variation in anything. The fact that precipitation does here, and that adding the effects of predator richness and island characteristics explains nearly all the variation in disease prevalence on these eight islands, suggests that we're getting to the heart of some basic ecological principles."


Contact: John Orrock
University of Wisconsin-Madison

Related biology news :

1. Amount of dust, pollen matters for cloud precipitation, climate change
2. Hind wings help butterflies make swift turns to evade predators, study finds
3. As super-predators, humans reshape their prey at super-natural speeds
4. Sexy or repulsive? Butterfly wings can be both to mates and predators
5. Predators ignore peculiar prey
6. Siberian jays use complex communication to mob predators
7. Venomous sea snakes play heads or tails with their predators
8. Lizards change their diet to avoid predators
9. Move over predators: Plants can control the food chain too -- from the bottom up
10. Return of top predators is key to ecological future
11. Making its predators tremble: Multiple defenses act synergistically in aspen
Post Your Comments:
(Date:11/18/2015)... York , November 18, 2015 ... Research has published a new market report titled  Gesture ... Trends, and Forecast, 2015 - 2021. According to the report, ... 2014 and is anticipated to reach US$29.1 bn by ... 2021. North America dominated ...
(Date:11/17/2015)... , November 17, 2015 ... au 19 novembre  2015.  --> Paris ... --> DERMALOG, le leader de l,innovation biométrique, ... la fois passeports et empreintes sur la même surface ... les passeports et l,autre pour les empreintes digitales. Désormais, ...
(Date:11/17/2015)... SOUTH EASTON, Mass. , Nov. 17, 2015 /PRNewswire/ ... "Company"), a leader in the development and sale of ... to the worldwide life sciences industry, today announced it ... closing of its $5 million Private Placement (the "Offering"), ... Offering to $4,025,000.  One or more additional closings are ...
Breaking Biology News(10 mins):
(Date:11/27/2015)... November 27, 2015 ... popularity of companion diagnostics is one of ... market with pharmaceutical companies and diagnostic manufacturers ... tests. . --> ... report on global cancer biomarkers market spread ...
(Date:11/25/2015)... -- PharmAthene, Inc. (NYSE MKT: PIP) announced  today that its ... (Rights Plan) in an effort to preserve the value ... 382 of the Internal Revenue Code (Code). ... its NOLs could be substantially limited if the Company ... of the Code. In general, an ownership change occurs ...
(Date:11/25/2015)... Nov. 25, 2015  Neurocrine Biosciences, Inc. (Nasdaq: ... President and CEO of Neurocrine Biosciences, will be presenting ... New York . ... website approximately 5 minutes prior to the presentation to ... the presentation will be available on the website approximately ...
(Date:11/25/2015)... PORTLAND, Oregon , November 25, 2015 /PRNewswire/ ... Deep Market Research Report is a professional and ... Genomics industry.      (Logo: ... basic overview of the industry including definitions, classifications, ... analysis is provided for the international markets including ...
Breaking Biology Technology: