SCREENING FOR SEXUALLY-TRANSMITTED DISEASES IN RURAL WOMEN IN PAPUA-NEW-GUINEA - ARE WHO THERAPEUTIC ALGORITHMS APPROPRIATE FOR CASE DETECTION

The presence of a large reservoir of untreated sexually transmitted di seases (STDs) in developing countries has prompted a number of suggest ions for improving case detection, including the use of clinical algor ithms and risk assessments to identify women likely to be infected whe n they present to clinics for other reasons. We used data from a commu nity-based study of STDs to develop and evaluate algorithms for detect ion of cervical infection with Chlamydia trachomatis or Neisseria gono rrhoeae, and for detection of vaginal infection with Trichomonas vagin alis or bacterial vaginosis. The algorithms were derived using data fr om 192 randomly selected women, then evaluated on 200 self-selected wo men. We evaluated the WHO algorithm for vaginal discharge in both grou ps. The prevalences of cervical and vaginal infection in the randomly selected group were 27% and 50%, respectively, and 23% and 52%, respec tively, in the self-selected group. The derived algorithms had high se nsitivities in both groups, but poor specificities in the self-selecte d women, and the positive predictive values were unacceptably low. The WHO algorithms had extremely low sensitivity for detecting either vag inal or cervical infection because relatively few women reported vagin al discharge. Simple algorithms and risk assessments are not valid for case detection in this population.