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Researchers Crack Genetic Code of  Sexually Transmitted Disease


An international team of scientists has cracked the genetic code of the parasite that causes one of the most prevalent sexually transmitted diseases in the world known as trichomoniasis. The research is expected to help people with the infection soon. VOA's Jessica Berman reports.

Up close, the single-celled bacterium that causes trichomoniasis is almost pretty to look as it propels itself in a rippling motion, according to researcher Jane Carlton.

"It's a single-celled organism. It has four flagella, or hairs, that sort of stick out the top of its head or apex," she explained. "And these it uses to move about the places. It's very motile. When you look under a microscope, you can see that it moves. It's very active."

But Trichomonas Vaginalis, which is the scientific name for the organism that causes the sexually transmitted disease, is anything but harmless.

The World Health Organization estimates that 170 million people worldwide are infected with trichomoniasis, a figure Carlton says may be a great underestimation.

She says the bacteria live in the urogenital tract of both men and women, who transmit it sexually. It is usually harmless in men, but Carlton says women develop an infection that can lead to major complications.

"The main cause for concern is the fact that the parasite produces an increased risk of infection with HIV 1, the virus that causes AIDS," she added. "And also it causes some pretty nasty pregnancy-associated problems, such as premature delivery and low birth weight."

Carlton, a parasitologist at New York University, led an effort by researchers in almost a dozen countries beginning in 2002 to map the genes of the trichomoniasis organism.

The preliminary DNA road map, mostly sequenced when Carleton was at the Institute for Genomic research in Rockville, Maryland, pinpointed some 26,000 genes, many of which differ from those of the human genome.

"You want to identify metabolic pathways which are present in the parasite, but not in the human host," she noted. "And then you can develop drugs that will attack those pathways, thereby killing the parasites and not the hosts and we've done that. We've definitely found proteins we can target."

One class of drugs that appears promising against trichomoniasis is currently used to treat AIDS. It targets an enzyme that is similar to one found in the DNA of Trichomonas Vaginalis.

The sequence of the trichomoniasis bacterium is published in the journal Science.