Lymphatic Filariasis elimination


Disease description and causality

lymphatic-filLymphatic filariasis is caused by thread-like parasitic worms of the species Wunchereria bancrofti, called filarie. These filarial parasites, in their adult stage, live in the vessels of the lymphatic system for 4-6 years, producing millions of very small larvae – immature microfilariae that circulate in the peripheral blood with a marked nocturnal or diurnal periodicity. The infection is transmitted by mosquitoes that bite infected humans and pick up the microfilariae from the blood.

Lymphatic filariasis acute manifestations are commonly in form of acute inflammatory attacks characterized by local symptoms such as swelling, warmth, redness, and extreme pain of the affected area, and general symptoms such as fever, chills, headache and weakness. Such symptoms occur in the limbs or in the scrotum, and are related to bacterial or fungal super-infection. Most pronounced chronic signs of the disease comprise of lymphoedema, elephantiasis, and hydrocele. The disease is rarely fatal but characteristically disfiguring, incapacitating resulting in stigmatization, isolation, and psychologically affecting patients.

Disease burden, distribution and impact

In Africa 406 million people are estimated to be at risk of lymphatic filariasis, representing 30% of the global burden. Most of them are living in remote and poor areas.

  • 39 countries in the tropical and equatorial climate of the Sub-Saharan Africa are suspected to be endemic.
  • Lymphatic filariasis is co-endemic with Loiasis in 9 countries and this is impeding the implementation of Preventive Chemotherapy (PCT)
  • 33 countries require PCT implementation.

Progress in the last 10 years

  • Systematic mapping of the distribution of the disease started in 1997-98 and 27 countries have completed mapping
  • At the end of 2011, 18 countries had started implementing PCT
  • Over 80 million people were treated under mass drug administration at the end of 2010
  • Achievement of interruption of transmission through mass drug administration has been demonstrated in two national programmes
  • Sustained annual review of the programme for direction and technical guidance.

Programme goals and objectives

The goal of Lymphatic Filariasis Programme is to interrupt transmission and reduce the at risk population to zero. The objectives are to:

  • Sustain annual treatment of entire at risk populations until transmission is interrupted;
  • Establish appropriate surveillance system;
  • Strengthen support for disability management within the health system; and
  • Strengthen partnership for lymphatic filariasis elimination.

Targets and milestones (up to 2020)

  • Complete the mapping of all the countries by 2013;
  • Start Multi Drug Administration (MDA) in all endemic areas by 2014 including loiasis co-endemic areas;
  • 70% of all the endemic countries have met the criteria of stopping interventions and entered into post intervention surveillance phase by 2016;
  • 70% of the countries verified as free of lymphatic filariasis and 30% in the post intervention surveillance phase by 2018; and
  • All countries verified free of lymphatic filariasis by 2020.

Major operational strategies

Lymphatic filariasis elimination programme aims at interrupting transmission of infection through annual mass drug administration of at risk populations. This is done using ivermectin or diethylcarbamazin citrate in combination with albendazole for 5- 6 years. The medicines used in the programme are donated. This is a component in the preventive chemotherapy strategy. Disability prevention and management through home-based care is carried out as a complementary strategy, as well as individual case management for hydroceles within the health system.

Major partners

Merck & Co. Inc, GlaxoSmithKline, The Global Alliance for Elimination of Lymphatic Filariasis partnership, Non-Governmental Development Organizations, Partners of the African Programme for Onchocerciasis Control and Global Network for Neglected Tropical Diseases.

Global Fact sheet on Lymphatic filariasis