Is trachoma on track for elimination by 2020? Monitoring and surveillance after mass drug administration with azithromycin for active trachoma in guinea bissau

06 Nov 2016
Giovanna Cowley, Eunice Teixeira Da Silva, Meno Nabicassa, Pedrozinho Duarte Pereira De Barros, Milena Mbote Blif, Robin Bailey, Anna Last

Background Guinea Bissau is a trachoma-endemic country that has pledged to eliminate blinding trachoma by 2020 by implementation of the SAFE strategy. Evidence for elimination is to be presented in a dossier to WHO. Mass drug administration (MDA) with azithromycin for active trachoma has been carried out in the Bijagos and Cacheu regions. Through collaboration with government and non-government agencies, we conducted coverage and impact surveys to evaluate success of MDA and build capacity in monitoring and surveillance activities within the Programa Nacional de Saude de Bissau. Our surveys demonstrate the feasibility of compiling the elimination dossier and show promising results.

Methods (1) Coverage survey (Bijagos): Seven households were randomly selected from 17 villages on five islands which had received MDA 1 month previously. Household members reported whether they had taken azithromycin and population coverage was calculated. (2) Impact survey (Cacheu): 15 households were randomly selected from 20 clusters. Trained ophthalmic nurses recorded cases of follicular trachoma (TF) amongst 1–9 year-olds and of trachomatous trichiasis (TT) amongst people aged 15 and above. Prevalence estimates of TF and TT were calculated.

Results (1) MDA Coverage (Bijagos): Estimated MDA coverage was 90.9% overall (n=518) and 94.4% amongst children aged 1–9. (2) Impact survey (Cacheu): 701 1–9 year-olds and 1557 >14 year-olds were examined. The estimated prevalence of TF1–9 was 0.3% and that of unoperated TT>14 was between 0.1 and 0.4%.

Conclusions These surveys provide evidence that MDA can achieve very high levels of coverage in remote and poorly accessible areas and can reduce TF to below the WHO elimination threshold. Successful TF elimination can allow focus to shift to operating TT, which remains a significant public health problem after MDA. These surveys demonstrate how sound epidemiological methods can be used in programmatic settings to evaluate elimination campaigns, guide future programme activities and contribute to global data collection.