Among the signs of anaplasmosis in cattle are yellow-colored carcasses. The disease is also called yellow bag or yellow fever because infected animals typically develop a jaundiced appearance. (Photo courtesy Professor Hans Coetzee)
Among the signs of anaplasmosis in cattle are yellow-colored carcasses. The disease is also called yellow bag or yellow fever because infected animals typically develop a jaundiced appearance. (Photo courtesy Professor Hans Coetzee)

Many cattle producers across the country are facing a new bully; and this tag-team is one tough cookie, creating havoc round-the-clock.


Secretly, she goes by Anna PM and he goes by AM Osis, but investigators tracking their every movement use just one name: it’s pronounced Ana-Plas-Mo-Sis

Those investigators are urging cattle producers and buyers to take precautions to avoid a sucker punch from the potentially deadly disease called anaplasmosis, which is now spreading through many northern states.

They’re also telling large-animal veterinarians to become well versed with everything from prevention to testing so they can help their clients avoid a blindside hit.

“Many producers don’t think about anaplasmosis until they have a problem, and some producers have never heard of the disease,” said Iowa State University College of Veterinary Medicine Professor Hans Coetzee (pronounced Could-see). “By the time veterinarians become involved, producers are seeing sick animals, abortions and death loss in a previously healthy herd, and it is not uncommon for the producers to have no idea what’s going on.”

More and more cattle in northern states are being stricken with anaplasmosis, which is caused by the parasite Anaplasma marginale.

Deer ticks and wood ticks, along with biting flies, including horse and stable flies, can transmit the disease from infected cattle to healthy ones.

But researchers are finding another culprit: producers themselves.

“Cattle producers represent a very significant source of transmission based on some of the outbreaks we’ve investigated,” said Coetzee, an internationally known expert on the disease, who starts Oct. 1 as department head of anatomy and physiology at the Kansas State University College of Veterinary Medicine.

“Typically what we see is transmission by infected needles, similar to what you see in humans with transmission of diseases such as HIV and hepatitis C. So controlling any potential exposure to contaminated blood — including needles and equipment — is critical to help ensure your cattle remain healthy.”

More on that in a moment; but first some key background.

Anaplasmosis is endemic to many southern states. Interestingly, when cattle under one year of age are exposed to the disease in these areas, they typically develop lifelong immunity to infection and never show any clinical signs of being sick, Coetzee said.

“The issue is when they get exposed to the disease once they are older than a year,” he noted. “That’s when they typically develop clinical signs and can actually get very sick and can even die.”

Coetzee said that’s why trying to keep anaplasmosis out of herds in endemic areas has become a balancing act.

“There is some benefit to having young calves exposed to anaplasmosis in endemic areas because they generally become immune to the disease, and that can create a situation of endemic stability,” he commented.

But there are some very important “buts” for every producer across the country to consider and act upon.

For those in the southern endemic areas, Coetzee said, “Your herds may still be at risk. Older cattle that have never been exposed to the disease can still get very sick and may die. That is why it’s important to visit with your veterinarian and develop a plan.”

It’s also imperative that producers in the endemic areas who market seedstock, or truck cattle to other states, have a plan, because if they ship anaplasmosis-infected animals elsewhere, their reputation is at stake.

“And on top of reputation is the issue of liability,” he said. “Part of a plan will involve screening herds and identifying any carriers.”

Coetzee noted that he believes anaplasmosis began spreading in recent years when cattle were being shipped north from drought-stricken southern states, including Texas.

“That is probably the most compelling reason why we’re seeing a lot more outbreaks of the disease in states like North and South Dakota, Iowa, Minnesota, Wisconsin and Michigan. Infected cattle are moving into these states where cattle have no immunity.”

As that happens, Coetzee said, ranchers start seeing their healthy, home-grown cattle develop jaundice, very high temperatures and anorexia. Some die, and others abort their calves. Not knowing the cause, ranchers call their veterinarians, and subsequent tests determine that anaplasmosis is the culprit.