Anthrax rears its ugly head again

By Russ Daly
Special to the Farm Forum

News of anthrax killing cattle in South Dakota isn’t unusual, but it’s still quite jolting to hear.

The latest report came a couple weeks ago. Nine cows in a southwestern South Dakota beef herd were found dead due to anthrax. In South Dakota, anthrax cases pop up essentially every year. Yet these reports really get the attention of veterinarians, cattle owners, and the general public. Why does anthrax pique our interest so much? The reasons probably vary depending on your particular walk of life.

For cattle producers, anthrax is the one disease they don’t want. When cattle get a disease like pinkeye or pneumonia, we can monitor it and treat and otherwise take care of the sick ones. Anthrax hitting a cow herd is like a lightning strike on a sunny day. It hits cows and bulls so quickly that signs of illness are non-existent. Dead animals are the only sign. Due to its swiftness and severity, anthrax is a dread disease for cattle producers.

For veterinarians, reports of anthrax make it rise higher on our list of the things that can kill a cow on pasture – the “differential diagnoses.” It then joins lightning, poisonous weeds, and blue-green algae on the list when vets investigate death losses. Sometimes these notices are good reminders that the disease isn’t confined to one part of the state. As a practicing vet, the critical piece of information for me about anthrax cases was “where?”. Although it could show up anywhere, a diagnosis near my practice area really got my attention. It forced me to consider anthrax more often as a possible cause of death, and to better guide my producers about preventive practices.

For regulatory vets and academics, anthrax reports help us understand the disease better. For example, we’ve always considered the anthrax vaccine to be very effective in cattle. So, for me, a critical piece of information from anthrax reports is the vaccination status of the herd. This particular Pennington County herd had not been vaccinated for anthrax. This reinforces my understanding of the role of vaccine in anthrax prevention. If we ever have a case of anthrax in vaccinated animals, that would force me to want to investigate further. So far (knock on wood) we haven’t needed to.

I’m also interested in the location of anthrax cases. I’ve come to recognize an “anthrax zone” in central South Dakota around the Missouri River. Herds in these areas don’t go without vaccinations, because of the higher incidence in the area. We know anthrax spores can live a very long time (years) in the soil: once we know the disease has been in an area, we can expect it there again in the future.

On the other hand, anthrax has been found in about every part of South Dakota over the years – so no one can consider their herd 100% safe. I know it’s sometimes a hard sell to some when I recommend cattle anywhere in South Dakota be vaccinated against anthrax, but I also know that it could pop up anywhere.

For public health people, finding anthrax in cattle grabs their attention because people can get the disease too. Fortunately, if people become infected from a cattle carcass, it doesn’t result in the sudden death we see in animals – although it does cause serious local infections. When a cattle anthrax case is identified, our Animal Industry Board does an extensive job of informing the producers on ways to protect themselves from the infection. Our public health people send reminders to area physicians to be aware of possible human cases coming into their clinics.

For the general public and the media, anthrax reports in cattle garner attention due to it simply being “anthrax” – a feared disease with bioterrorism implications. Most of my students now are too young to remember the “weaponized” anthrax powder that was sent through the mail and killed people from inhalational anthrax, but it’s still on the minds of many of us.

Fortunately for the public at large, anthrax is simply a cattle issue in South Dakota. Unfortunately for cattle producers and veterinarians, it’s a disease that can appear to come out of nowhere, with potentially devastating results for a herd.

Russ Daly, DVM, is the Extension veterinarian at South Dakota State University. He can be reached via e-mail at russell.daly@sdstate.edu or at 605-688-5171.