Yaws is a tropical infection of the skin, bones and joints that is caused by Treponema pallidum, a subspecies of the bacterium that causes syphilis. As it is only found in humans and is easily treated by antibiotics, it is an ideal candidate for eradication.
The infection is spread through direct contact through minor injuries such as cuts and scratches and, if left untreated, can lead to chronic deformities and disability.
WHO’s existing strategy to eradicate the infection by 2020 involves a single round of mass treatment with the antibiotic azithromycin, followed by targeted treatment programmes every three to six months to identify and treat all symptomatic cases and their contacts.
Associate Professor Alyssa Barry from the Walter and Eliza Hall Institute said that the findings point to a need for multiple rounds of mass drug administration in order to capture those not present during the first round. “Research also showed a much bigger geographical area should be targeted for the mass treatment, in order to protect against the migration of infection in people from surrounding communities,” she said. “Finally, there is a clear need for ongoing monitoring to prevent the spread of drug-resistant strains, following world-first evidence of antibiotic resistance in yaws bacteria.”