"Information about existing infection will help farmers separate
herds so infected animals can't cross-contaminate the rest of the herd.
The goal is to create
Johne's-free herds," said Wu, whose molecular research is aimed
at determining how paratuberculosis wreaks its destruction in animals,
and developing treatments or cures for Johne's disease. "Being
able to test more samples allows us to know the extent of the illness'
spread and to learn more about its workings."
According to the U.S. Department of Agriculture, about 22 percent of
the nation's dairy herds and about 24 percent of those in the
Midwest, including Indiana are infected with the intestinal illness.
To make matters worse, the agency says at least 45 percent of U.S. dairy
producers don't know about the disease.
It is voluntary to have animals tested for Johne's, although some states
now prohibit transport of infected animals and/or require that they
be branded to show Johne's infection. No scientific evidence exists
that consumption of meat or milk from infected animals can cause the
malady in people.
Educating producers about Johne's disease and its control is a priority
of the Indiana State Board of Animal Health, says Thomas Conner, director
of the board's Cattle and Ruminant Division. For many years, the agency
has required reporting of the disease and has recorded test results
and maintained herd records.
Although a vaccine exists that will reduce the
symptoms and prolong an animal's life, it does not prevent infection,
Conner says. The vaccine is only available for cattle under a special
agreement between the state veterinarian, the producer and the producer's
local veterinarian.
Wu and her team of researchers do much of the Johne's testing for Indiana
in the Animal Disease Diagnostic Laboratory on the Purdue campus. Their
main focus however, is studying the disease process, especially the
mechanisms involved with the bacteria.
The knowledge could lead to new drugs or vaccines to treat and prevent
Johne's disease and possibly even related diseases, such as Crohn's.
Johne's disease can be spread to animals from infected feed, water
and colostrums, and females with high infection can spread it in utero
to fetuses. Most animals are infected at less than six months of age,
although symptoms don't appear for two years to five years.
Besides dairy cattle, other types of cattle, deer, elk, sheep, goats,
antelope and bison also can fall victim. But it is more prevalent in
animals kept in confined conditions, Conner says.
Contact Ching Ching Wu at wuc@purdue.edu
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