Research Helps Block Spread of TB in Animals

Armed with new knowledge about transmission of tuberculosis between animals, Agricultural Research Service scientists are helping with the effort to eradicate tuberculosis in animals in the United States. The presence of TB in wild white-tailed deer in Michigan poses a serious threat to the eradication program. To help fight that problem, ARS scientists in Ames, Iowa, have developed the first animal model to study TB transmission in white-tailed deer.

ARS microbiologist Diana Whipple and ARS veterinarian Mitchell V. Palmer have used the method to experimentally infect captive white-tailed deer with Mycobacterium bovis, the organism that causes tuberculosis in cattle. This method helps the researchers study the transmission of TB from experimentally infected deer to noninfected deer in research pens at ARS’ National Animal Disease Center in Ames.

One significant finding has already emerged from their studies. The researchers have identified a possible route of transmission of M. bovis from experimentally infected deer to other noninfected animals. They found that deer saliva as well as nasal and tonsil secretions contain M. bovis. Therefore, a cow or another deer might become infected with M. bovis by eating feed contaminated with these secretions, according to Whipple.

Fingerprints of genetic material called DNA show that both the wild and captive deer in Michigan are infected with the identical strain of M. bovis recovered from coyotes, raccoons, a bear, and cattle.

An article about this work appears in the February issue of Agricultural Research magazine. The article can be found on the world wide web at:

ARS is the USDA’s chief research agency.

Scientific contact: Diana Whipple, ARS National Animal Disease Center, Ames, Iowa, phone (515) 663-7325, fax (515) 663-7458, dwhipple@nadc.ars.usda.gov.