September 12, 2013 | Vol. 117 -- No. 21

Serious infections being spread by tick bites

When my dog and I walk along the Snake River during the warm seasons of the year, we can both come home with a tick or two. I’m used to feeling those little legs on my skin or scalp and picking off the critters. If I’m lucky, I get to them before they attach and start sucking my blood. Because I’ve been doing this all my life I don’t get stressed out about ticks, but I do know they can carry certain diseases.

Recently the Shots Website of National Public Radio reported that scientists have made an advance about an unusual illness that befell two farmers in Missouri in 2009. The men came down with bad fevers, nausea and diarrhea. They were sick enough they sought medical attention and it was discovered the platelet counts in their blood had dropped significantly.

At first, they were treated with antibiotics for some sort of bacterial infection. But the treatments didn’t help. A doctor at Heartland Regional Medical Center in Missouri then sent samples of the farmers’ blood to the Centers for Disease Control and Prevention. When the samples were analyzed, medical researchers turned up a new virus, not one previously known to science. They named it the Heartland virus.

Happily, the sick men ultimately got better, their bodies beating back the infection that had made them so ill. But the question remained: how were they exposed to the virus? The basic clues were that the two men worked outdoors, were in the same state, and had been bitten by ticks before coming down sick.

Federal researchers have now figured out how the virus was transmitted to the men. In 2012 they collected some 50,000 ticks (what a job!), including taking some ticks off dogs and horses at the farms of the men who had become ill. Analyzing the ticks, they have found the Heartland virus.

“It’s the first time anyone has found (the virus) in the wild, in the environment,” said researcher Harry Savage to Shots. “It means the virus is yet another tick-borne disease in the U.S.”

The Heartland virus has so far been detected in only one kind of tick, a species called the lone star tick. (The bug isn’t named for Texas, but for a little white dot that adults carry on their backs.) And only the juvenile ticks, called nymphs, have been shown to carry the virus. About 1 in 500 of the nymphs has the virus.

“If you were looking for Lyme in Connecticut, there would be more ticks infected,” Savage said. “But for a virus, (1 in 500) is a substantial number.”

The lone star tick is found in the lower Midwest, the southeast, and along the coast of New York and New England. The Heartland virus gives people living in those regions another reason to check themselves when they come in from the outdoors during the warm seasons of the year.

Happy tick hunting, everyone!

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.

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