Source: AgriLife Today
Reports of anthrax in deer at a Kinney County ranch by the Texas Animal Health Commission has revived interest in understanding the disease and how to prevent its spread, said Texas A&M AgriLife Extension Service experts.
“One of the important things to know about these recent instances of anthrax is that they were isolated and all occurred in deer on a high-fenced ranch,” said Emily Grant, AgriLife Extension agriculture and natural resource agent for Kinney County. “That area has been quarantined, so the risk of any further exposure to wildlife or livestock outside that contained space is highly unlikely.”
However, Grant noted, these new occurrences underscore the need to remind area landowners to be mindful of the disease and how to recognize, report and protect against it.
“It’s important for area landowners to be cognizant of the fact that anthrax can and does occasionally occur here and to be mindful of the conditions that cause it,” she said. “It’s also important to know the symptoms and what to do in the event you encounter an animal that has the disease.”
Many common species are susceptible to anthrax, including sheep, goats, horses, cattle, swine, domestic or exotic deer and humans, said Dr. Maureen Frank, AgriLife Extension wildlife specialist, Uvalde.
“Wild deer are usually the hardest hit, because unlike livestock, they can move around and spread the infection to other areas,” Frank said.
In Texas, anthrax typically occurs in an area of southwest Texas that includes portions of Crockett, Edwards, Kinney, Maverick, Sutton, Uvalde and Val Verde counties. Most anthrax-caused animal deaths occur during warm weather, particularly in July and August. The spores that cause the disease become dormant again once the weather cools, but there have been cases of anthrax during the winter.
“For many people, the word anthrax brings to mind a biological weapon, but the disease occurs naturally in many parts of the world where soil types and weather are favorable to it,” said John Tomecek, AgriLife Extension wildlife specialist, San Angelo. “It is caused by the bacterium Bacillus anthracis, which produces spores as a way to survive unfavorable conditions. These spores, which can lie dormant in the soil for many years, are largely responsible for the disease. But unlike weaponized anthrax, spores are not typically airborne in sufficient concentrations to cause infection.”
Tomecek said anthrax outbreaks are spurred by mild, wet winters and springs followed by dry spells and intense summertime drought. Surface water from rains relocate the spores in the dusty soil and create “hot spots” where animals graze.
“Anthrax outbreaks in Texas are especially common in ‘drought-breaking’ years,” he said. “Under these conditions, spores become concentrated on the soil surface and on vegetation, where foraging animals can become exposed to the disease.”
Frank said animals with the disease have symptoms that typically appear three to seven days after exposure to anthrax spores.
“Once the symptoms appear, most exposed wildlife or livestock will die quickly, often within 48 hours. Multiple deaths in a very short time span are common,” she said. “Some of the symptoms are similar to those of other diseases, including lethargy, a loss of coordination, staggering and difficulty breathing. A symptom characteristic of anthrax is blood oozing from the animal’s orifices – the nose, mouth and anus – although it is important to note that not all affected animals will display this symptom.”
Sudden death without any symptoms, especially during warm months, may also indicate anthrax infections, Frank noted.
“Anthrax is a U.S. Department of Agriculture reportable disease and must be reported to the Texas Animal Health Commission (TAHC),” she said. “This means that if you suspect anthrax in your animals, you need to seek assistance from a veterinary professional or TAHC. They will give advice on how to best manage the situation. Failure to report a suspected case is a crime, and reporting is not a burden – quick reporting helps protect landowners, livestock and wildlife. If livestock do test positive, they will need to be quarantined and vaccinated.”
For wild animals, Texas Parks and Wildlife Department and TAHC staff will work together to determine if the case is actually anthrax and help manage it appropriately, she said.
“Report any suspected instance of anthrax to the veterinarians and they will send tissue samples from suspected cases to the Texas Veterinary Medical Diagnostic Laboratory for confirmation,” Frank explained.
She said if a landowner notices 10 or more wild or exotic deer dying at a time and the carcasses show bleeding characteristic of anthrax, it is imperative to immediately move livestock away from the carcasses.
“If you have livestock death that appears to be from anthrax, move remaining animals to a safe pasture as well,” she said.
Both Frank and Tomecek said the best method of disposing of an affected carcass is by incineration and that wood, diesel and gasoline are approved by the Texas Commission on Environmental Quality (TCEQ) for incineration. If weather conditions preclude burning, they recommend burying the dead animal deep in the pasture where they died.
“Anytime you handle an ill animal, including one with anthrax, use protective equipment and take safety precautions,” Frank said. “Taking simple steps to reduce contact with aerosolized spores and infected blood can protect you from exposure to anthrax and other serious diseases.”
The experts said to use extreme caution when decontaminating infected premises or when handling live animals or carcasses suspected of infection. Wear long sleeves, pants, rubber gloves and a facemask if possible.
“Airborne infections are rare in the pasture, but you can rupture a bloated animal when moving it, which can release high concentrations of anthrax spores,” Tomecek said. “Most human cases of anthrax are caused by handling carcasses, but ranchers and other agricultural workers have a higher risk of the disease in their day-to-day work.”
Tomecek said ranchers in regions where the disease is common should consider anthrax vaccinations for livestock.
“There is no approved vaccine for deer,” he said. “And if a livestock infection occurs in a confinement scenario such as a barn, pen or paddock, remove all bedding, manure and other materials and burn them. Then ask your local veterinarian or TAHC contact how best to sanitize working facilities.”
As most hunting occurs during the cooler months, the experts noted hunters are generally not at risk from the disease, but caution dictates using personal protection, including wearing a long-sleeved shirt and rubber gloves, plus covering any open wounds on the carcass while field dressing the animal.
“If you suspect an animal had any disease when harvested, do not consume any part of it and be very selective about taking sick-looking deer,” Tomecek said. “And remember that wild pigs are also susceptible to the disease but do not exhibit symptoms as strongly as deer and other livestock.”
He said those finding animals that may have died from anthrax should not attempt to salvage antlers, horns, heads or any other body parts.
“If you feel you may have come in contact with a live animal or carcass affected by anthrax, wash your hands thoroughly to remove any lingering spores,” he said. “And contact a physician if you feel ill or notice any strange blisters or sores where you may have come into contact.”
Tomecek and Frank said the prompt reporting of instances in which animals are acting abnormally and exhibiting symptoms known to be associated with anthrax are key to the early detection and management of outbreaks.
For more information, see the publication “Anthrax: Conditions, Symptoms and Advice for Landowners” authored by Tomecek, Frank and Dr. Terry Hensley, AgriLife Extension veterinarian and assistant agency director, Texas Veterinary Medical Diagnostic Laboratory. This publication can be found at: http://agrilife.org/texnat/files/2016/09/EWF-060.pdf.
Additional information can be found at:
— Texas Animal Health Commission, http://www.tahc.state.tx.us
— Texas Parks and Wildlife Department, http://www.tpwd.texas.gov
— Texas A&M AgriLife Extension Service, http://agrilifeextension.tamu.edu
— Texas Veterinary Medical Association, https://tvma.azurewebsites.net
Source: AgriLife Today