Tiny sand flies that spread disfiguring infection have arrived in U.S.

Sand flies are tiny — a quarter of the size of a mosquito — and live in warm climates. Because of global warming, they are migrating to new regions, like the United States, and are bringing with them an unwelcome passenger: a single-cell parasite that can cause disfiguring scars on people who are bitten by sand flies.

CNN says the flies are so small that they can go through "ordinary mosquito nets on tents or window screens," and most people don't even realize they've been bitten until they show signs of a leishmaniasis infection.

As reported by CNN:

[Dr. Mary Kamb, a medical epidemiologist at the US Centers for Disease Control and Prevention in Atlanta] and her colleagues at the CDC say they've now detected leishmaniasis in a number of tissue samples from patients who say they have not traveled outside the United States. They conducted a genetic analysis of these samples and collected them into a new study that was presented today at the annual meeting of the American Society of Tropical Medicine and Hygiene. These patients all had leishmaniasis skin infections, which start with a small bump that erupts into ulcerous sores days to weeks after a sand fly bite.

"People could be asymptomatic and not develop anything, but when people are symptomatic, they develop ulcers on their skin and sometimes it starts like a little tiny volcano with a crater in it," Kamb said. These sores often erupt near the site of a recent bite. The parasite disables nerves in the skin, so the sores generally are not painful but tend to scar and can be disfiguring, especially if they occur on a person's face.

Sand flies have been found as far north as Ohio and Maryland. About half a dozen leishmaniasis cases are being reported yearly in the U.S. in people with no travel history.

Pro-tip — don't do an image search on "leishmaniasis."