On average, the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) diagnoses two or three positive cases of anthrax annually in summer months, but so far in 2019, the agency has confirmed 10 positive cases in several species, including exotic antelope, goats, horses, white-tailed deer and cattle.
All positive cases have come from a Texas region with a historical presence of anthrax, TVMDL said.
“Detection of this summer’s increased number of anthrax cases is just one example of the ongoing role TVMDL plays in protecting animal health, human health, a safe food supply and the financial well-being of the second-largest part of the Texas economy,” TVMDL director Dr. Bruce Akey said.
Anthrax, caused by Bacillus anthracis, is a spore-forming bacterium that occurs naturally in soil in certain parts of Texas and around the world, TVMDL said. As the veterinary diagnostic laboratory for Texas, TVMDL conducts thousands of surveillance tests each year for the early detection of high-consequence diseases that could have a devastating effect on the livestock and poultry industries.
B. anthracis spores can lie dormant in soil for several years, or even decades. Typically, the bacterium infects grazing animals when they ingest contaminated soil, TVMDL said, noting that animals may also be exposed to anthrax via inhalation and through the skin; however, those are less common routes of transmission.
Anthrax is on the federal list of potential bioterrorism agents and is a zoonotic disease — a disease that can also infect people. Therefore, anyone handling animals suspected of having exposure to anthrax should take necessary precautions, such as wearing long sleeves and gloves.
Once a suspected anthrax specimen arrives at the laboratory, TVMDL’s microbiologists obtain a pure bacteriological sample: isolation. After isolation, microbiologists identify diseases, like B. anthracis, on the basis of physical characteristics of the bacteria itself and how it grows on culture plates. Following identification, the microbiologists use additional specific tests to confirm the identity of the bacteria.
When it comes to identifying, tracking and stopping the spread of diseases like anthrax, TVMDL is one of many partners working together to protect Texas livestock. In accordance with state and federal regulations, TVMDL must report certain high-consequence diseases to various regulatory agencies, such as the Texas Animal Health Commission, the Department of State Health Services and, in the case of a potential bioterrorism agent like anthrax, the U.S. Centers for Disease Control & Prevention and the U.S. Department of Agriculture. Once reported, regulatory agencies work with affected parties to control the spread of the disease.
Anthrax in livestock, wildlife
According to TVMDL, clinical signs of anthrax in cattle, sheep, goats and deer may include fever, disorientation, labored breathing, muscle tremors, congested mucous membranes and collapse. It is possible for sudden death to occur without the presence of clinical signs; an animal can appear healthy and be dead within a matter of a few hours.
In addition to the above clinical signs, horses may show signs of colic, enteritis and swelling of the neck and lower abdomen, the agency said.
TVMDL encourages animal owners who have an interest in testing for anthrax to first contact a private veterinarian who can assist with evaluating suspect animals and the proper collection of samples. Once testing has been conducted, a TVMDL veterinary diagnostician can consult with private veterinarians and animal owners on additional testing and sampling requirements.