An ambitious testing program to help Texas regain its tuberculosis-free status has discovered a case of bovine tuberculosis in a Hamilton County dairy.
The testing program, which began in November 2003, was designed by the Texas Animal Health Commission (TAHC) to find out if TB resided elsewhere in the state. Officials are working with 450 TB-certified private veterinary practitioners to test 2,400 of the state’s seedstock beef herds and all 831 dairy herds before September 2004.
“Finding an infected herd this early in the testing effort indicates we are on the right track," says Bob Hillman, Texas' state veterinarian and executive director for TAHC. The targeted, intensive herd testing is a major component of Texas' plan to regain its TB-free ranking, which was downgraded in 2002.
Texas officials say the discovery of this case of TB proves its surveillance program works. The U.S. Department of Agriculture is underwriting the cost of the program. There is no cost to producers for the TB herd test.
Out of 57 purebred herds and 82 dairies tested since November, the Hamilton County dairy is the first found to be infected, says Hillman. In late December, the Hamilton County dairy was quarantined, after a number of animals reacted to TB skin tests. TAHC veterinarians collected tissue from several of the animals and forwarded the samples for confirmation testing to the National Veterinary Services Laboratory in Ames, Iowa. Lab results last week confirmed the preliminary diagnosis. The owner has two options, he can depopulate the herd and receive an indemnity payment from USDA, or he may retain the herd under quarantine for repeated testing, until all infected animals have been identified and removed. A complete epidemiological investigation will be conducted to determine how infection was introduced into the dairy, and if it has spread to other herds.
Texas initially earned the its TB-free ranking in 2000, but lost it in 2002, after two infected cattle herds were detected in Texas in 2001. In August 2003, a third infected cattle herd was detected and depopulated in Zavala County.
Similar testing is underway in California, New Mexico and Michigan — other states that have lost their TB-free ranking. And earlier this month Arizona found a herd infected with TB. If a second case is found within 48 months, Arizona could lose its TB-free status too.
Texas dairy and seedstock producers are urged to contact TAHC to get their herds tested. USDA funding for herd surveillance testing is available another eight months.
Texas Animal Health Commission press release