A skin condition that causes sores the size of a half-dollar known as the Baghdad boil has been found in nine people in Texas, researchers say.

More: What Is Leishmaniasis?

The disease, formally known as leishmaniasis, is common in South America, Mexico and the Middle East and had been found before in troops returning from Iraq and Afghanistan, but is now showing up in people who have not traveled to the area, University of Texas Southwestern Medical Center researchers said.

The nonhealing sores usually last for 6 to 12 months. Because they are often mistaken for a staph infection, patients sometimes get multiple courses of standard antibiotics without success.

The disease is caused by a single-celled parasite called Leishmania, and special cultures must be done in order to confirm the diagnosis of leishmaniasis.

Researcher Dr. Kent Aftergut said doctors in North Texas must now be on the lookout for the disease. He also said the cases seem to be from a Mexican strain of the disesase, which doesn't last as long and does not become a full-body disease.

It is thought that the disease spreads when sand flies bite wood rats, then bite a person.

Insecticides, bug repellant and protective clothing while working in areas where sand flies might be present should help reduce the risk, Aftergut said.