Wisconsin researchers: CWD found in soil near mineral licks
Earlier this year, University of Illinois researchers began considering the relationship between soil characteristics and the presence of deer with chronic wasting disease.
They said their findings could eventually help explain the movement of CWD across the landscape.
The hope is that new research out of the University of Wisconsin-Madison will provide even more of the same: Scientists report that, for the first time, research has detected prions responsible for CWD in samples taken from sites where deer congregate.
According to the story out of the University of Wisconsin-Madison, which conducted the study, scientists searched for prions at mineral licks — areas where deer seek out essential nutrients and minerals — in the CWD endemic area across south-central Wisconsin. Out of 11 sites, nine had detectable levels of the disease-causing misfolded proteins, the story said, and prions were found both in soil and in water from the sites, as well as in nearby fecal samples from one site.
“This is the first time that anyone has demonstrated the existence of prions in naturally contaminated soil,” Michael Samuel, an emeritus professor of wildlife ecology who helped lead the UW study, said in the story.
It is not clear if the quantity of soil-dwelling prions detected in the UW study are sufficient to infect deer, the story said, adding that the significance of prion-contaminated environments in the spread and persistence of CWD among free-ranging deer also remains unknown.
The research does help confirm longstanding suspicions that prions can accumulate in the environment in areas such as mineral licks or feeding and baiting sites where deer congregate, and scientists believe environmental reservoirs of prions could serve as an additional transmission route of CWD, which also passes between deer through direct contact, the story said.
In the University of Illinois study, scientists were looking at – among other things – what happens to a patch of soil after a deer urinates on it, as chronicled in a blog by Keri Butt of Illinois Outdoor News.
“When infected deer urinate, defecate, or salivate, they can shed prions. When a susceptible deer comes along and licks, ingests, or inhales infected soil, it could pick up a prion,” said Nohra Mateus-Pinilla, veterinary epidemiologist at the Illinois Natural History Survey and the Illinois study co-author.
Of the UW study, Don Waller, a professor of botany and environmental studies at UW who researches Wisconsin’s deer herds but was not involved in the study, said, “It’s not easy to test for CWD, but this result suggests we should be looking for hot-spots of CWD prions in the environment and doing all we can to cover them up so animals can’t get to them. We may also want to do more testing in other animal species to see which may be vulnerable to CWD infection.”