Yet Another Reason To Say Ick to Ticks

By Nancy Shute

Published August 4, 2011 at 12:49 PM MDT

A new bacterial species linked to a flu-like illness in humans has been found in deer ticks, like this one, in Minnesota and Wisconsin.

Ticks may be most notorious for spreading Lyme disease, but the tiny arachnids pass around plenty of other nasty diseases. Now they've got a new sickening hitchhiker to boast about — a just-discovered species of the ehrlichia bacterium that's making people ill in the Upper Midwest.

Scientists at the Mayo Clinic identified the new species when it showed up in DNA tests done on people who got sick with flu-like symptoms in Minnesota and Wisconsin, starting in 2009. The tests didn't match two known forms of ehrlichia, which usually infect people in the South. More testing of people and ticks and — voila! A new, yet-to-be-named species. The discovery was reported in the New England Journal of Medicine.

So far 25 people are known to have been sickened by the new species. No doubt more will be as doctors start looking for it. It's spread by deer ticks, which are also the culprits in Lyme disease.

The other forms of ehrlichiosis haven't been a huge health problem; fewer than five deaths a year in the United States were reported in the past decade. But new so-called vector-borne diseases spread never fail to worry public health types, because many of the world's worst diseases are spread by insects. Think malaria and mosquitoes, or plague and fleas. West Nile Virus is still circulating, and killing people, 12 years after mosquitoes first started to spread it in the U.S.

Wondering if you have this trendy new bug? People with erlichiosis have flu-like symptoms: fever, headache, muscle aches. It's treatable with the antibiotic doxycycline, but it's understandably easy for people to not associate those symptoms with a tick-borne illness.

The best way to avoid getting erlichiosis, or any tick-borne disease, is to use insect repellent and wear long pants when outside, according to the federal Center for Disease Control and Prevention. For tips on how to keep ticks at bay and remove those that latch on, see the University of Rhode Island's TickEncounter website.