What is lymphatic filariasis?

Lymphatic filariasis is transmitted via mosquito bite. The infection is usually first acquired during childhood.

It is one of a group of conditions known as neglected tropical diseases (NTDs). Once a person is infected, adult worms lodge in the body’s lymphatic vessels, affecting the lymphatic system. The worms can live for six to eight years, producing millions of larvae that circulate in the infected person’s blood.

The disease can cause abnormally enlarged body parts, which can be extremely painful and can lead to permanent physical changes. This condition, called lymphoedema, is highly stigmatised. In men, it can cause hydrocele, a form of lymphoedema that causes the scrotum to swell, leading to pain and disability.

The debilitating symptoms mean many people are unable to work, and children miss school to care for family members. The associated stigma can have a devastating impact on those affected, as well as their families and communities.

Sightsavers is fighting hard to eliminate lymphatic filariasis in the countries in which we work by 2030.

While river blindness is transmitted by the black fly and lymphatic filariasis by the mosquito, both diseases are caused by an infection of a filarial worm and often occur in the same places. Where they are co-endemic, Sightsavers coordinates treatments for these two diseases using Mectizan® tablets, donated by pharmaceutical company Merck Sharpe & Dohme (MSD), and albendazole tablets, donated by GlaxoSmithKline.

In countries where river blindness is not co-endemic, lymphatic filariasis is treated using diethylcarbamazine, produced by Eisai, and albendazole tablets, donated by GlaxoSmithKline.

In 2023, we provided more than 16 million treatments for LF worldwide. We also trained more than 100,000 local volunteers to distribute medication via mass drug administration to treat a range of neglected tropical diseases, including lymphatic filariasis.

Although people with advanced lymphoedema cannot be cured, the symptoms can be eased through surgery and care. Sightsavers works with WASH (water, sanitation and hygiene) organisations to help households access clean water and facilities, so people can clean their limbs and care for their skin. Symptoms can also be helped by elevating limbs and by wearing footwear. Hydrocele can be cured through surgery, transforming the lives of men affected.