Anthrax Alert

Veterinarians and cattle producers are called on to be especially watchful for signs of anthrax in some regions this spring. The mix of drought and flooding across much of the country sets the stage for those areas with a history of the spore-forming bacteria to be at a heightened risk of exposure.

Gerald Stokka, North Dakota State University Extension veterinarian, told DTN the spores created by the bacteria Bacillus anthracis, are very hardy. They can survive for years under the right conditions, hatching and infecting susceptible cattle that come into contact with them.

"While it is relatively rare, there is a pattern to it, a geographical pattern," Stokka told DTN. "Where anthrax has occurred in the past, the risk is greater that it will occur again. Cattle ingest the spores, and now you have the potential for infection. So, if you or your neighbors have experienced anthrax in the past, there might be a greater risk this year for reinfection."

Stokka noted that often the only signs of anthrax infection are dead cattle. While cattle can die without signs of illness for a number of reasons, including lightning strikes, clostridial infections and toxicities, anthrax should always be considered a possible cause until it is ruled out.

The veterinarian advised taking precautions when handling animals that might have died from anthrax, adding that veterinarians generally won't want to perform a necropsy if anthrax is suspected. A blood test can be used to check and confirm the suspected diagnosis.

If anthrax is confirmed, vaccinations can be given to the rest of the herd. Stokka said it's important to remember anthrax is a reportable disease and treatment and reporting are generally coordinated through the office of the state veterinarian.

The anthrax vaccine is commercially available as a live-attenuated (non-disease-causing) spore vaccine. The dose is 1 cc, given subcutaneously in the neck region. All adult cattle and calves should be administered the vaccine in susceptible areas once the herd veterinarian deems it necessary.

Stokka adds that treatment with antibiotics may interfere with the immune response to the vaccine. However, if faced with an outbreak, he said administering an antibiotic and a vaccine concurrently has been shown to be effective. He stressed it's important to consult with the herd veterinarian for specific recommendations.

Along with vaccines and possibly antibiotics, Stokka said producers should try to remove remaining cattle from the area where the suspected anthrax deaths occurred.

A common misconception is that clostridial vaccines protect against anthrax, as well as blackleg. Stokka said this is not the case, and explained that while there are some similarities, these are different families of organisms.

Anthrax, as noted above, is caused by the spore-forming bacteria Bacillus anthracis. Blackleg, however, is caused by Clostridium chauvoei. Both anthrax and blackleg infect animals through bacterial spores, usually ingested while grazing.

For more information on anthrax, its sources, symptoms, animal disposal, treatment and controls, go to https://www.ag.ndsu.edu/….

Victoria Myers can be reached at vicki.myers@dtn.com

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