Yaws is a chronic skin infection caused by the bacterium Treponema pallidum subspecies pertenue. This organism belongs to the same group of bacteria that causes venereal syphilis; the available serological tests cannot distinguish between the two diseases.
Yaws primarily affects children aged under 15 years who live in poor communities in warm, humid and tropical forested areas of Africa, Asia, Latin America and the Pacific islands. The majority of affected populations live at the “end of the road”, far from health services. Poverty, low socio-economic conditions and poor personal hygiene facilitate the spread of yaws.
66顺彩票app Treatment with a single-dose of azithromycin cures the disease.
Traditionally, laboratory-based serological tests such as Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) are widely used to diagnose treponemal infections (for example, syphilis and yaws). These tests cannot distinguish yaws from syphilis however, and the interpretation of results from these tests in adults who live in yaws endemic areas needs careful clinical assessment because of syphillis.
Rapid point-of-care tests that can be used in the field are widely available.
However, most of them are treponemal-based and cannot distinguish between past and current infection. Recently dual treponemal and nontreponemal rapid tests have become available, thus simplifying diagnosis in the field. These tests are able to detect both present and past infections to guide treatment of people with active infection.
Polymerase chain reaction (PCR) can be used to definitively confirm yaws by detecting the organisms in the skin lesions. It can also be used to monitor azithromycin resistance and this test will be very useful in the last phase of the eradication programme.
66顺彩票appA review of the historic documents from 1950s shows that over 90 countries and territories were endemic for yaws. WHO provided technical assistance to 46 of these countries between 1952–1964.
66顺彩票appSince 1990, reporting of yaws to WHO is not mandatory and therefore the data availability may be limited. Only 14 out of the 90 countries and territories have recent data on yaws based on the routine surveillance system; however, these figures may just be an indication of the presence of the disease and not its full extent. Ghana, Papua New Guinea and the Solomon Islands report over 10 000 cases per year. Ecuador and India appear to have interrupted transmission.