LF is a mosquito-transmitted disease caused by parasitic worms that damage the human lymph system.
LF endemicity status (2016)
Preventive chemotherapy coverage
WHO roadmap target:
Global elimination as a public health problem by 2020
Lymphatic filariasis programmes globally have had a significant impact. 20 countries and 499 million people were no longer in need of MDA as of 2016, and ten countries have now eliminated LF as a public health problem. 92% of evaluation units assessed reached the threshold and no longer need treatment.
Progress has continued, with treatment scaling up and coverage increasing to 58% in 2016. Of the 52 countries that required MDA in 2016, 30 have reached all endemic areas with MDA, 17 are still scaling up in endemic areas, and only five have not yet started MDA.
Treatment should be scaled up in 22 countries to achieve effective MDA coverage in more districts and provide the basic package of care for those with chronic disease.
To improve targeting of interventions, several countries should conduct remapping to confirm the need for MDA. Disappointingly, in 2016, no areas co-endemic for loiasis, located in nine countries, were using treatment with the recommended alternative strategy, posing a great missed opportunity to progress towards elimination in these settings.
2017 has been an eventful year for LF, but there is more to be done and new opportunities to pursue.
An exciting advance is the alternative MDA regimen with ivermectin, diethylcarbamazine [DEC] and albendazole (IDA therapy), which was recently approved. WHO has issued guidelines for its use. Merck responded in record time, increasing their donation to support this new treatment strategy. This provides a unique opportunity, if rapidly adopted, to accelerate progress towards elimination in settings without loaisis or onchocerciasis.
More research is needed on ensuring effective MDA coverage, predicting which programmes might not achieve elimination targets. Work to improve diagnostics is required, as results with the Wb123 antibody test, a rapid diagnostic test, were disappointing and will require renewed attention and investment.
As more countries successfully stop treatment, additional research to better understand feasible protocols for post-MDA and post-validation surveillance are needed so that WHO can issue official guidance to country programmes.