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Lab Spotlight: NWRC - Detecting Bovine Tuberculosis in Cattle Breath


Here USDA scientists test a new device used to detect the presence of volatile organic compounds in the breath of cattle infected with bovine tuberculosis.

Volatile organic compounds (VOCs) are organic compounds that often emit unique odors and emission patterns. Because of these unique characteristics, VOCs have been identified as potential tools in disease surveillance. Recently, USDA National Wildlife Research Center (NWRC) scientists and colleagues from USDA-APHIS Veterinary Services, Tel-Aviv University, and Technion-Israel Institute of Technology developed a method for collecting and analyzing VOCs from cattle. The scientists tested the method during an outbreak of bovine tuberculosis (TB) in cattle in the United States. Gas chromatography and mass spectrometry analyses revealed the presence of two VOCs associated with a bovine TB infection in the exhaled breath of infected cattle. Based on these results, a nanotechnology-based array of sensors was then tailored for the detection of bovine TB-infected cattle via breath. The system successfully identified all bovine TB-infected animals, while only 21 percent of the noninfected animals were classified as bovine TB-infected (i.e., were false positives). This technique could form the basis for an efficient, real-time, and noninvasive screening for new bovine TB infections on dairy farms.

Tuberculosis is a contagious, bacterial disease of both animals and humans. Bovine TB can be transmitted from livestock to humans and to other animals. The significance of the disease is reflected in the USDA’s efforts to eradicate TB from the United States. The TB eradication program has made significant progress since it was initiated in 1917. By the mid-1990s, only a few known infected cattle herds remained, suggesting that eradication of the disease in the United States was forthcoming. However, deer in Michigan remain infected. Between 1975 and 1998, bovine TB was documented in Michigan’s white-tailed deer with increasing frequency, and scientific evidence revealed that infected deer transmitted the disease to some of Michigan’s cattle. In 2000, the Secretary of Agriculture enacted a Declaration of Emergency for bovine TB, citing threats to livestock, and public health and safety. In 2001, NWRC initiated research to reduce or eliminate the transmission of this disease from wildlife to cattle and humans. The research is especially critical in light of recent bovine TB cases documented in California, Colorado, Michigan, Minnesota, and New Mexico.

Photo by Jack Rhyan.

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