Abstract
Purpose: :
The World Health Organization's program to eliminate blinding trachoma relies on repeated mass antibiotic administrations. If infection is not locally eliminated, then infection may return, as there is little evidence that other measures prevent it from recurring. In villages with moderate trachoma, repeated treatments have come close to elimination. In hyper–endemic communities, repeated treatments have eliminated infection from pre–school children, however no study has yet demonstrated elimination from the entire community. Here we survey all members of 3 villages which have received 6 mass treatments and are likely candidates for elimination.
Methods: :
In a study monitoring ocular chlamydial infection in the Gurage district of Ethiopia, all members of 24 villages received biannual mass antibiotic treatments with azithromycin for 24 months (children under the age of 1 year were not treated due to approval issues). Children aged 1–5 years were monitored prior to each treatment. Eight of the 24 villages failed to demonstrate any PCR–proven trachoma infection for at least the two most recent visits. Based on population size (<400 individuals) and baseline prevalence of infection (>30%), three of these villages were chosen for further study. Every village member was censused, and conjunctival samples were obtained for PCR (Roche Amplicor).
Results: :
Pre–treatment prevalence of infection in 1–5 year old children was 34, 45, and 50% in the 3 villages. At 30 months, 6 months after the 6th biannual treatment, all individuals were examined and swabbed for the presence of chlamydial DNA. The number of individuals from each village was 162, 208, and 262. Of these 632 individuals, we identified three cases in one village, all in preschool children, aged 2–4 years. One case occurred in an adult from the second village. All individuals were PCR–negative in the final village.
Conclusions: :
Local elimination of infectious trachoma from severely affected communities is feasible with biannual, repeated mass azithromycin distributions. However, elimination in pre–school children does not necessarily mean that infection will not be identified at subsequent visits, either due to re–infection from outside the community or from older age groups within the community.
Keywords: trachoma • bacterial disease • clinical (human) or epidemiologic studies: prevalence/incidence