HOUSTON - A new species of bacterium that causes leprosy has been identified through intensive genetic analysis of a pair of lethal infections, a research team reports in the December issue of the American Journal of Clinical Pathology.
All cases of leprosy, an ancient disease that still maims and kills in the developing world, previously had been thought to be caused by a single species of bacterium, said lead author Xiang-Yang Han, M.D., Ph.D., associate professor in Laboratory Medicine at The University of Texas M. D. Anderson Cancer Center.
"We have identified a second species of leprosy mycobacterium, and in identifying this killing organism we've better defined the disease that it causes, diffuse lepromatous leprosy (DLL)." Han said. DLL occurs mainly in Mexico and the Caribbean.
There are hundreds of thousands of new cases of leprosy worldwide each year, but the disease is rare in the United States, with 100-200 new cases annually, mostly among immigrants. Leprosy initially attacks skin and nerve cells. It can be successfully treated with antibiotics in its early and intermediate stages.
R. Geetha Nair, M.D., a physician with Maricopa Integrated Health System in Phoenix, contacted Han in 2007 for help confirming a possible leprosy diagnosis in a patient who died that February.
The patient, a 53-year-old man originally from Mexico, was admitted that month for treatment of extensive leg wounds. While undergoing antibiotic treatment and additional diagnostic testing the next day, he was stricken with high fever and shock. He died after 10 days in intensive care.
Analysis of autopsied tissue at the Phoenix hospital suggested a diagnosis of diffuse lepromatous leprosy, a form first described in Mexico in 1852. Han said DLL uniquely attacks a patient's skin vasculature, blocking or impeding blood flow. This leads to extensive skin death at late stage and may cause secondary infection and fatal s
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University of Texas M. D. Anderson Cancer Center