As a cow has been confirmed to have recently died of Anthrax in Hardeman County Texas, it seems a good time to revisit the issue. Please find below information related to Anthrax.
Anthrax Update 08/19/2021
Prepared by: Tom Hairgrove, DVM, Joe Paschal, PhD, Ron Gill, PhD; Texas A&M Agrilife Extension
Anthrax is a bacteria (Bacillus anthracis) that causes disease in cattle, sheep, goats, horses, exotics, swine, dogs, and cats. Domesticated and wild herbivores such as cattle, sheep, goats, and deer have a higher risk of contracting the disease and dying. However, anthrax also affects humans, so take appropriate precautions handling dead livestock.
Anthrax is often associated with heavy rains after a prolonged drought or dry summer following heavy spring rains. The bacteria release spores that are highly resistant to sunlight, drying, and chemicals. The spores contaminate the environment and spread the disease. Surface contamination spores on the pasture can last up to three years. The spores can indefinitely remain in the deep soil, especially in alkaline soils high in nitrogen or organic matter. As a result, animals ingest contaminated forage or water or come in contact with tissues, particularly the bones of animals that have died from anthrax, and ingest the spores.
When spores enter the animal (by ingestion or other avenues), they change into a vegetative form which causes disease. The spores penetrate the intact tissues in the animal’s oral cavity and travel to the lymph nodes to multiply and enter the bloodstream. They invade all body tissues, producing deadly toxins. The time frame from when the spore enters the animal until disease occurs (incubation period) varies from 3 to 14 days. Animals are usually found dead and with no previous signs of sickness.
Swine tend to exhibit disease symptoms such as swelling in the neck and head, interfering with breathing and swallowing, which can be confused with hog cholera or African Swine Fever. Feral hogs, wild and feral canids, and scavenger birds such as buzzards, and ravens that feed on dead livestock can spread anthrax for considerable distances, and their feces can contaminate stock ponds. Less commonly implicated, Tabanid flies (horse flies, deer flies, cedar flies, etc.) are vectors capable of spreading anthrax.
If a pond or stream has dead animals in it or a lot of bird feces, hog wallows, etc., try to provide another water source if possible. If at all feasible and with extreme caution, remove deads from ponds or streams and burn if possible. However, do not drag carcasses for any distance as it will leave more anthrax bacteria in the ground, which will form spores. Every effort should be made to keep livestock away from contaminated sources, if at all possible, until at least ten days post-vaccination.
Other conditions associated with sudden death in livestock are colic, blackleg and associated clostridial diseases, grass tetany, blue-green algae, anaplasmosis, lead poisoning, toxic plants, and lighting strike. Animals infected with anthrax are usually bloated, do not exhibit rigor mortis, and have a bloody discharge from all body orifices. In cases of the sudden death of livestock, contact your veterinarian to assist with diagnosis. Do not disturb carcasses; conditions related to the livestock deaths are likely to be common conditions listed above but rule out anthrax before invasive necropsies.
Control of Anthrax
If confirmed anthrax, the Texas Animal Health Commission (TAHC) will quarantine infected and exposed animals in your herd, advise on proper disposal of carcasses, and require treatment and vaccination as necessary to control and eradicate the disease. Unless otherwise specified, the quarantine will be released ten days after vaccination of the herd with a product approved by the TAHC and after proper disposal of carcasses.
Colorado Serum Company of Denver, Colorado, produces the current vaccine approved for use in Texas. A one ml (cc) dose administered subcutaneously followed by a second dose in 2-3 weeks is recommended for herds affected with or exposed to the disease. The vaccine protects for approximately six to eight months.
Vaccination for at least three years following an anthrax outbreak is prudent and recommended. Anthrax usually occurs in the summer or early fall, and considering the short duration of protection from the vaccine, annual vaccination in the spring is most effective.
Unpublished work at Texas A&M shows that penned deer and exotic wildlife receive protection for about 4 to 6 months following delivery of vaccine through remote delivery devices.
Work with your veterinarian to develop a biosecurity program for your herd that includes anthrax vaccination and prevention.
Anthrax and Human concerns
Most people who contract anthrax are exposed while working with infected animals or animal products such as wool, hides, or hair. When spores enter their bodies, the spores can be activated and become anthrax bacteria. The bacteria can multiply, invade the body, produce toxins (poisons), and cause severe illness.
Human anthrax is associated with three different avenues of the spores entering the body
- Inhalation anthrax occurs when a person inhales spores in the air (aerosolized) during the industrial processing of contaminated materials, such as wool, hides, or hair.
- Cutaneous anthrax can occur when workers handling contaminated animal products have spores infect a cut or scrape on their skin
- Gastrointestinal anthrax results from eating raw or undercooked meat infected with anthrax and usually occurs in countries where food safety inspection is lacking, and anthrax is common. In the United States, gastrointestinal anthrax is rare.
Producers should take precautions when gathering, vaccinating, and otherwise dealing with potentially infected cattle. In areas where tabanid flies are common, wear long sleeve shirts, apply fly repellents, and other precautions recommended by the local health authorities.
Hunters should be aware and careful.
Note: In addition, the general public should be mindful not to handle bones or antler sheds in areas at risk for anthrax
