Lymphatic filariasis (LF) is a debilitating disease caused by parasitic worms that affect the human lymphatic system and can lead to severe swelling of the lower limbs (elephantiasis) and scrotum (hydrocele). Transmitted by mosquitoes that transfer the worm parasites from person to person through their bites, LF is a leading cause of disability globally.¹ Act | West supports elimination of LF by providing funding and technical support to national ministries of health to implement interventions recommended by the WHO, including annual mass treatment with medicines that treat the disease and stop transmission of the parasite, and surveys to assess treatment impact. Act | West also supports countries to document success through the WHO dossier process for validation of elimination of LF as a public health problem. 

LF is considered a public health problem in 702 districts in 11 countries that receive support from Act | West.² After mass treatment, LF prevalence has been reduced to levels that make the risk of transmission unlikely in 88% of these districts (619). Although post-treatment surveillance is ongoing, it’s reasonable to say that over 135 million people living in these districts are no longer at risk of LF infection, elephantiasis and hydrocele. 

Act | West continues to support annual treatment in approximately 83 districts across 7 countries.³ As of FY22, four Act | West countries have stopped MDA in all endemic districts and are now under surveillance—Benin, Cameroon, Mali and Togo. 100% of ever endemic districts are in post-treatment surveillance in Togo, Benin, Mali, and Cameroon. Over 80% of ever endemic districts are in post-treatment in Niger, Burkina Faso, Ghana, and Senegal. In addition, since FY19, Côte d’Ivoire and Guinea have conducted the pre-transmission assessment survey in 69 districts and 12 districts, respectively, to determine whether they could progress to a stop-MDA survey (TAS1). 

1. Weekly Epidemiological Record No 41, 2019, 94, 457-472. 11 October 2019, World Health Organization 
2. LF is present in Benin, Burkina Faso, Cameroon, Côte D’Ivoire, Ghana, Guinea, Mali, Niger, Senegal and Sierra Leone. The World Health Organization validated elimination of LF as public health problem in Togo in 2017. 
3. The number of districts that receive Act | West support varies from year to year.  

Lymphatic Filariasis lifecycle diagram

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