September 15, 2007
Rare, Non-Fatal Skin Disease Found in N. Texans
By Sherry Jacobson, The Dallas Morning News
Dermatologists in North Texas were alerted Friday to be on the lookout for a rare skin infection caused by a parasite that may have migrated north from the Mexican border.
Doctors at UT Southwestern Medical Center said they have identified nine cases of the skin disease in North Texans in recent months. The Centers for Disease Control and Prevention confirmed that all nine people, both adults and children, were infected by the parasite, Leishmania mexicana.
Typically found in Mexico or along the Texas border, it is carried by wood-burrowing rats and spread by tiny sand flies that bite both the rats and humans.
"None of the North Texas cases had traveled south or to parts of the world where the disease is endemic, which suggests they got it here," said Dr. Kent Aftergut, a Dallas dermatologist who identified the first apparent local infection in March.
Weldon Hatch, a 58-year-old Waxahachie man, said he sought Dr. Aftergut's care after two small red spots appeared on his shoulder in February. Later, the lesions grew to the size of a quarter, became itchy and painful.
"All the creams and salves didn't do anything," he said. "So my doctor gave up, and I went to an expert."
Dr. Aftergut diagnosed the skin ailment and later shared Mr. Hatch's case with other Dallas-area dermatologists, who realized they had treated similar cases.
The other leishmaniasis cases were confirmed in Hillsboro in Hill County, Tom Bean in Grayson County, Anna and Nevada in Collin County, Savoy in Fannin County, North Richland Hills in Tarrant County, and in Glenn Heights, which straddles Dallas and Ellis counties.
Dr. Barbara Herwaldt of the CDC's division of parasitic diseases said Texans should not be especially fearful of being infected, especially because doctors are being alerted to watch for it.
"It shouldn't be a cause for alarm because physicians in Texas will be looking for certain skin lesions that don't go away," she said. "When you know to look for something, you know to diagnose it."
Several treatments are available, doctors said, though the lesions can heal by themselves over time.
Although the parasite's presence in North Texas appears to be new, doctors can't say for sure.
"It's entirely possible that there were cases like this that were never reported before because we weren't looking for them," said Dr. Erin Welch, an assistant professor of dermatology at UT Southwestern. "What we know is that these are all isolated cases. The people weren't travelers, and they had no connection to each other."
Dr. R. Doug Hardy, infectious disease specialist at UT Southwestern, said he couldn't help but believe that something changed to allow the parasite to move north.
"We've had intermittent cases along the Mexican border," he said. "But to have all these cases so close together, outside the border, in kids and adults without travel, is very unusual."
A few were guessing that environmental changes, including higher temperatures, could have allowed infected rats and sand flies to move into North Texas.
Dr. Hardy noted that experiments have been conducted to try to isolate the parasite from local sand flies. So far, nothing has been confirmed. "It's also possible that we have a different insect or rodent in North Texas that can carry the parasite," he said.
Leishmaniasis (pronounced Leash -- man -- EYE -- a -- sis) typically has been diagnosed among people who had traveled to the Middle East and South America. In recent years, U.S. soldiers have returned from Iraq and Afghanistan with leishmaniasis, often referred to as a "Baghdad boil."
"The good news is that it's not something that typically goes beyond the skin," Dr. Herwaldt said. "This is something we know how to handle, and it's not spread by casual contact."
ABOUT THE SKIN DISEASE
What is leishmaniasis?
It's an infectious skin disease spread by sand flies.
What should I do if I develop a boil?
Go to your doctor and be tested for the parasite that causes the disease.
How serious is the disease?
It's a mild disease, though the boil could be painful and large. It often is misdiagnosed and can take as long as a year to heal.
How do you avoid being infected?
You should use insect repellent and wear protective clothing when outdoors between dusk and dawn, when the flies usually feed.
SOURCE: UT Southwestern Medical Center