The cost of boarding my horse has gone up … again. I can’t say that I blame the barn manager. With the continuing drought in my part of the country, hay is becoming scarce and seemingly worth its weight in gold. Higher feed costs are simply being passed on to the owners of the horses stabled at the facility. On the other hand, my horse isn’t eating hay right now; he’s on pasture. But, it is getting pretty dry and weedy out there so I’m sure (or at least I hope) they’ll start putting hay out soon.

The drought is causing horse owners and livestock producers to worry about more than just the price of hay these days. Over 60 cattle on several ranches in northeastern Colorado have died from anthrax infections this month, and the lack of rain is probably a major contributing factor.

Bacillus anthracis, the bacteria that causes anthrax, is a fascinating organism. Under the right conditions, it produces spores that can survive for decades in the soil. When environmental stress levels rise (drought, heavy rains, and soil disturbances are often to blame) the spores become active and capable of infecting any warm-blooded animal. Spores can be inhaled, ingested, or can enter the body through cuts in the skin or insect bites.

Most naturally occurring cases of anthrax in the United States occur west of the Mississippi river, but it isn’t commonly diagnosed anywhere in this country. The Colorado State University Extension Service reports that anthrax last appeared in Colorado thirty-one years ago.

Often, the first sign that anthrax is becoming active in a particular area is a sudden die off of previously healthy animals — cattle and sheep are especially susceptible. Clinical signs of illness can include swelling around the head and face, staggering, tremors, difficulty breathing, hot and swollen skin lesions, and collapse, but death may occur so quickly that these symptoms aren’t observed by the animals’ caretakers. Dogs and cats can contract anthrax, but it is rare because these species have an innate resistance to the disease. When treatment is started before the bacteria invade the bloodstream, a lengthy course of antibiotics can cure many individuals of anthrax.

An anthrax vaccine is available for livestock and horses, but cases are typically so rare that most individuals don’t receive it. That changes in the face of an outbreak. Cattle surrounding those that have died have now been vaccinated, and should be protected once their immune systems have a chance to fully respond.

I’m not rushing out to vaccinate my horse against anthrax, though. The affected cattle all lived more than 200 miles from my hometown in an area that has received even less rain than we have. Hopefully with fall and winter will come some wet weather (but not too much!), and we won’t hear about anthrax in our area for another few decades.

Dr. Jennifer Coates

Image: Jay Petersen / via Shutterstock