During the early years, Dearing and her colleagues checked their traps wearing protective gear that looked like space suits, inspiring the nickname "hantanauts".
"We still didn't understand the risk of trapping mice and contracting hantavirus," she says. "We didn't understand the risk to personnel so we took extreme precautions."
Now scientists have a better understanding of how hantavirus is transmitted. Mice get it from other mice, probably through bites, while humans get it by breathing in mouse urine and feces during activities such as sweeping out a garage. Humans can't get it by handling infected mice or even by being bitten, so the "hantanauts" have been able to shed their space suits and check traps unencumbered.
The new study looked at the overall number of captured mice and the number that were infected in the spring and fall of 2004, 2005 and 2006.
Seasonal heavy rains in the U.S. Southwest spur the growth of plants such as juniper, sagebrush and spring-blooming annuals. While deer mice do not feed on such vegetation, they directly depend on it because they eat seeds and plant-eating insects.
The satellite images came from Moderate Resolution Imaging Spectroradiometer (MODIS), a sensor on NASA's Terra satellite. The images of the study site were processed using four different vegetation indices mathematical techniques for turning satellite data into plant-cover measurements. Three of the four indices measure green light reflecting from chlorophyll in plants. One measures infrared light absorbed by water in plant leaves. The researchers measured changes in plant cover from 2003 to 2006.
Greenery Blooms, then Mouse Population Booms
The study answered two questions: which vegetation indices are the best predictors of hantavirus risk and how long does it take for that risk to peak after surges in plant growth?<
|Contact: Lee J. Siegel|
University of Utah