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In search of a treatment, Tech biology professor studies parasite that inflicts millions of people around the world: Elusive enemy

MARLENA HARTZ
AVALANCHE-JOURNAL

The fridge is in a lab, not a kitchen. And instead of milk and eggs, it holds parasites.

They float in perfume-sized bottles of pink solution. Texas Tech assistant professor Kai Zhang, in a long, white lab coat, plucks a bottle from the stack and places it under a microscope.

"It's a fascinating organism," he says of the parasite called leishmania. The thin 34-year-old, originally from China, assures, "You won't get it by looking at it."

About 12 million people worldwide, traditionally in developing countries, have leishmaniasis, a disease with many forms. But lately more Americans, specifically soldiers deployed to the Middle East, are contracting the parasite, of which there are dozens of species.

 

Earlier this year, Zhang pinpointed a gene in the parasite that when removed renders it ineffective in mice. He plans to publish his findings in 2008 and hopes the discovery will help him develop an effective drug to treat leishmania in humans.

Magnified, the parasite - in one stage - resembles a pea-pod with a long worm-like tail. One of the most common forms affects the skin, causing volcano-like sores that can take months to years to heal and leave horrible scars. Some people are left so disfigured by the disease they've committed suicide, Zhang said.

Another more serious form settles in internal organs and, if untreated, can lead to death.

Humans get the disease from the bites of infected sand flies and rodents. Typically, it's contracted in tropical or sub-tropical regions, such as South America, the Middle East, Mexico and South Texas.

Among soldiers in the Middle East, the disease is known as "Baghdad Boil." Thousands of soldiers deployed to the region have contracted leishmaniasis. In a two-year period, 2002 to 2004, the Centers for Disease Control confirmed 522 cases of cutaneous leishmania - the form that affects the skin - in military personnel deployed to Iraq, Afghanistan and Kuwait.

"One soldier can come back with thousands of lesions," said Zhang, who is focusing on that form of the disease.

This year in Texas, there have been four confirmed cases of the disease among people who had not traveled to places where the parasite is usually found. In North Texas, nine cases have been confirmed in the last two years.

Texas Health Department officials are trying to determine what's caused the infections, which are unusual for North Texas. They believe something's caused either wood rats or sand flies to move north.

Zhang said some theorize warmer weather or infected military personnel returning from the Mideast have contributed to the spread. However, person-to-person transmission is rare.

"There is a level of concern ... (But) there is no reason to sound an alarm, not at this point," said Zhang, who does not know what has caused the move north in Texas.

Still, he believes more attention should be given to the historically understudied disease.

There is no vaccine or preventative medicine and few effective medicines exist, partly because pharmaceutical companies aren't willing to invest in drugs for a disease that mainly afflicts the poor, Zhang said.

Available medicines are so expensive and toxic, many doctors advise not to use them, Zhang said.

"You have to look at the burden of the disease," Zhang said. "The loss of quality of life, the suffering... If you add up these things, (the burden of leishmania is) tremendous.

"It's an important pathogen that's kind of been neglected," he said.

In his lab, nothing could be further from the truth.

"What he is trying to do is a remarkable thing," said Michael San Francisco, a colleague of Zhang's in the department of biological sciences.

Zhang calls his progress in treating mice with leishmania promising. But it will take time to reach his ultimate goal, finding a treatment for humans.

He needs to conduct more research, he said, and he's currently searching for federal sources of funding.

(The Associated Press contributed to this report.)