Lymphatic Filariasis

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Lymphatic filariasis (LF) is a painful and disfiguring disease. While the infection is usually acquired in childhood, its visible manifestations occur later in life, causing temporary or permanent disability.

It is caused by a species of filarial round worms transmitted by mostquitoes, with up to 90% of all infections being Wuchereria bancrofti. In some parts of Asia, LF is caused by Brugia malayi and Brugia timori. It is estimated that 120 million people are currently infected with LF, with 40 million suffering from serious incapacitation and disfigurement.

The main strategy to control and eliminate LF is once-yearly mass treatment in areas where prevalence of infection exceeds 1%. Maps of LF distribution that can be used by control programme staff are therefore invaluable. Here, we provide maps highlighting the location of LF surveys, often based on data that were previously unpublished or only accessible from private and otherwise restricted sources. We also provide predictive risk maps of the distribution of LF. Guided by these predictive maps are control planning maps, which identify districts requiring mass treatment based on WHO treatment recommendations.

As control is implemented, maps of the progress in control can help highlight success and indicate where further effort is required. For LF, these are provided as treatment coverage, indicating the proportion of the target population receiving deworming medication as part of national programmes.