March 26 (HealthDay News) -- An international team of researchers has finally isolated from the environment the organism that causes devastating and disfiguring ulcers that primarily plague poorer populations in Africa, according to a new report.

The study into the cause of Buruli ulcers also supports the idea that the organism, Mycobacterium ulcerans, is transmitted to humans not from person-to-person contact but from "environmental aquatic niches" where possibly animals, insects or other aquatic items carry the pathogen.

The study was published March 26 in the online, open-access journal PLoS Neglected Tropical Diseases.

Buruli ulcer is a necrotizing disease that sometimes produces massive, disfiguring skin ulcers and can have a huge social impact on the affected. The disease occurs predominantly in impoverished, tropical, rural areas of Africa, where the incidence has been increasing, surpassing tuberculosis and leprosy (two other diseases caused by mycobacteria) in some regions.

Although it has long been believed that Mycobacterium ulcerans is an environmental pathogen transmitted to humans from its aquatic sources, the organism had never been previously isolated from its environmental source.

"Our findings support the concept that Mycobacterium ulcerans is a pathogen of humans with an aquatic environmental niche and will have positive consequences for the control of this neglected and socially important tropical disease," the study's authors wrote.

In a related commentary published by the PLoS Neglected Tropical Diseases, Tim Stinear of Monash University and Paul Johnson of Austin Hospital, both in Australia, wrote that the new study is a major achievement that "will serve as the definitive reference point" in scientists' search for the precise source and mode of transmission of Mycobacterium ulcerans. Neither Stinear nor Johnson were involved in the study.

SOURCE: Public Library of Science, news release, March 25, 2008