Researchers Aid Efforts to Identify TB in Michigan Deer

Agricultural Research Service animal health experts are helping federal and state officials investigate the source and extent of tuberculosis in white-tailed deer in Michigan.

The ARS scientists have joined USDA's Animal and Plant Health Inspection Service (APHIS), the Michigan State Department of Agricultureand the Michigan Department of Natural Resources in the study. Five Michigan counties have reported wild white-tailed deer infected with Mycobacterium bovis, the organism that causes cattle tuberculosis. TB can spread from animals to humans.

Until now, no recognized wildlife reservoir for tuberculosis has existed in the United States, according to Diana L. Whipple, a microbiologist at the ARS National Animal Disease Center in Ames, Iowa. The outbreak of tuberculosis among Michigan deer and elk threatens a successful cattle TB eradication program that began in the United States in 1917.

Currently used skin tests do not detect all of the animals with TB. A blood test for diagnosis of TB in deer and elk also misses infected animals and is quite expensive. The primary means of detection of TB in cattle is carcass inspection after slaughter, but not all infected cattle show signs of disease. For a successful eradication program, other tests must be developed and used in conjunction with meat inspection.

In a few months, ARS researchers will evaluate a new blood test for deer developed by Australian researchers. In the meantime, they recommend more efficient use of tools to detect cattle TB. More infected cattle can be detected by using both the skin and blood tests than by using either test alone. Regulatory officials also recognize the importance of minimal handling while administering these tests. Humans don't get tuberculosis from eating or drinking milk from infected animals because pasteurization and appropriate cooking temperatures kill the M. bovis organism.

Scientific contact: Diana L. Whipple, ARS National Animal Disease Center, Ames, Iowa, phone (515) 239-8377, fax (515) 239-8458, [email protected].