Second positive case of beef cattle disease detected but likely won’t become widespread, expert says

Less than two weeks after officials confirmed a disease affecting beef cattle was found in Van Buren County in southeast Iowa, experts have found another positive case.

The second positive detection was also in southeast Iowa, said Grant Dewell, associate professor and Iowa State University Extension and Outreach beef veterinarian.

Theileriosis, the disease affecting beef cattle, infects red and white blood cells in cows, leading to anemia and difficulty breathing. It spreads through parasites in Asian Longhorned Ticks.

In the first reported case of the disease, Dewell said about 20 percent of cows in the 100-head herd died from it. However, Dewell said it’s typically not as fatal.

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The Asian Longhorned Tick — which is about the size of a sesame seed — is an invasive tick that was found in the United States for the first time in 2017. The tick is native to eastern China, Japan and Korea.

Dewell said the tick’s movement throughout Iowa is likely due to the movement of deer that carried the tick.

However, Dewell said he doesn’t anticipate the infection becoming too widespread throughout Iowa.

“Some of the early models that focus on the tick population say that Iowa is not a very good habitat for the tick, and they basically said it would probably stay in the southern two or three counties and maybe go up the Mississippi River a little bit, but most of the state would remain without the tick,” he said.

Dewell said the ticks prefer tall grass areas, so northwest to north-central Iowa will likely have less tick habitat due to much of the land being in agriculture.

“It's going to be harder for it to move into other parts of the state, but it could,” he said. We will “have to follow that in the next few years and see exactly how it moves.”

Although it can be fatal for cattle, Dewell said the disease poses no health risk to humans.

“The tick, although it will get on people, doesn't really like people as a host. It prefers ungulates, like cattle, deer, sheep … those types of animals are what is its preferred host,” he said.

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Dewell said that cattle infected with Theileriosis will be lethargic or exercise-intolerant because their red blood cell count is low. He said the cow’s mouth and eyes might look pale and have a “jaundice look” to them.

As of now, there is no treatment for the disease, but Dewell said infected cattle should be treated symptomatically, by giving them fluids. He said that in some cases, a blood transfusion is possible as well.

With the size of cattle and how much blood they have, Dewell said a few ticks aren’t a problem. But when a cow has a thousand ticks on them, it’s a bigger concern.

But when it comes to prevention, Dewell said the state will have to be “a little more aggressive at tick control.”

Dewell said two tick control methods could include spraying cattle with insecticides to prevent the tick from latching from the animal.

“The other thing we can do is keep our pastures low so that we don't get that tall grass. That is going to limit that habitat for that tick,” he said. “But that’s a little challenging in southeastern Iowa, because tall grass and brushes is pretty common, so but it's something that we're going to have to be a little more cognizant about.”

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

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Comments: olivia.cohen@thegazette.com