The WHO Alliance for Global Elimination of Trachoma by 2020 has increased the need to identify ocular chlamydial infections by clinical examination in areas of both high and low prevalence. The relationship between clinically active trachoma (as defined by clinical examination) and chlamydial infection is known for areas with hyperendemic trachoma, but not for areas with a low prevalence of the clinical disease. In the present study, we examined, photographed, and DNA tested the conjunctivae of children in the Surkhet district of mid-western Nepal, an area known to have a low prevalence of clinically active trachoma. Although 6% of the children aged 10 years and under were found to have clinically active trachoma, none were found to have chlamydia infection by the most sensitive DNA amplification tests available. A very low prevalence of clinically active trachoma is not necessarily evidence of the presence of chlamydial infection. Therefore, the WHO policy of not recommending an intensive trachoma control effort when the prevalence of clinically active trachoma is less than 10% in children is appropriate for this area of Nepal.
PIP: This article assesses the reliability of clinical diagnosis in identifying trachoma in a low prevalence area in Nepal. WHO¿s Alliance for Global Elimination of Trachoma by the year 2020 depends on the identification of communities in which blinding trachoma is present and of individuals in these communities who are seeking treatment. All children aged 1-10 from 6 villages in the Surkhet district of the Bheri zone underwent clinical tests, which were administered between November 17 and December 1, 1997. 726 out of 765 children were examined. 125 among these were further evaluated by photography and DNA testing on their right conjunctivae. Clinically active disease was found in 46 out of 726 children seen by the first examiner. Photographic evaluation showed that 32 of these 46 children had clinically active disease, while 14 of 79 children were found negative of the disease on examination. The results revealed that there was a low prevalence of active conjunctival disease in this area: only 6% of the children were clinically active on examination, and none were found to have chlamydia infection as assessed by the most sensitive DNA amplification test available. The WHO policy of not recommending an intensive trachoma control effort when the prevalence of clinically active trachoma is less than 10% in children is therefore appropriate for this area in Nepal. Clinical examination is the only feasible way of estimating the prevalence of infection; however, very low prevalence of active trachoma is not evidence for the presence of chlamydial infection.