Food Safety Consortium researchers have made some advances in researching
tuberculosis in cattle and swine. Tests in two aspects of the problem are
being conducted by Consortium affiliated personnel at the National Animal
Disease Center in Ames, Iowa.
Carole Bolin, an NADC research leader and a Consortium principal investigator,
conducted tests for diagnosis of bovine tuberculosis with NADC researchers
Diana Whipple and Belinda Goff. They sought to determine if tuberculin skin
tests used in the U.S., Canada and Mexico are compatible with each other,
an important issue with the passage of the North American Free Trade Agreement.
The tuberculins used for skin testing in the three countries are prepared
by different methods and from different strains of the bacterium Mycobacterium
bovis. The researchers compared tuberculins from each country to determine
if there is a need to standardize the tuberculins used in North America.
Cattle from a herd with bovine tuberculosis reacted similarly to all three
tuberculins with small variation among the responses. Cattle tested positively
for M. bovis most often when the Mexican tuberculin was used. But
the research team concluded that there was no need to standardize the tuberculins.
Plans are being made to use swine in studies by the NADC team to research
the risk of M. bovis infection caused by the consumption of meat
contaminated by the organism. The project began with studies determine if
swine could be used as an animal model of human tuberculosis. The researchers
found through their experiments that swine are susceptible to infection
with M. bovis when inoculated. Lesions characteristic of tuberculosis
were visible as early as two weeks following high doses of the inoculations
and in 30 days following low dosages.