What is lymphatic filariasis?

Lymphatic filariasis is a serious disease, with millions of people globally at risk. It can cause a range of symptoms, but is often characterised by abnormal enlargement of body parts.

Salifat sits down with her right leg in a bowl. A health care worker stands next her pouring water on her leg from a teapot.

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.

Watch our video to learn more about the disease.

120 million
people worldwide are affected by lymphatic filariasis
47 countries
need preventative treatment for the disease
863 million
people are currently at risk of contracting it

How is lymphatic filariasis treated?

A boy holds a tablet used to treat neglected tropical diseases.


A combined dose of two medicines is given every year to people in high-risk areas by local volunteer community-directed distributors.

A close-up of a health worker helping a patient to wash their leg, which has a large sore on it. The health worker is wearing gloves.

Medical care

Although people suffering from advanced lymphatic filariasis cannot be cured, the symptoms can be eased through surgery and care.

A woman working in a science laboratory.


Research is undertaken to evaluate, inform and improve our programme strategies, helping to eliminate this disease more quickly and fairly.

What we’re doing

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 2022, we provided more than 53 million treatments for LF worldwide. We also trained more than 225,000 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.

A nurse helps a woman learn how to care for her swollen limb caused by lymphatic filariasis.

Caring for patients in Democratic Republic of Congo

An estimated 42 million people in DRC need treatment for lymphatic filariasis. Find out how Sightsavers is working to protect communities.

What we’re doing

Find out about other diseases we treat

Neglected tropical diseases

More about lymphatic filariasis

Sightsavers blog

Expanding the Reaching the Last Mile Fund: a game-changer for river blindness and lymphatic filariasis

The funding pledge is a huge step towards eliminating the diseases.

Phil Downs, December 2023
Salifat smiles at the camera
Sightsavers blog

The world is making progress on eliminating lymphatic filariasis – yet we urgently need to finish the work

Sightsavers’ Roland Bougma shares what action needs to be taken to ensure the disease is eliminated as a public health problem globally.

Roland Bougma, November 2023
Two women stand in a flooded area outside a house, where they are checking a mosquito trap.
Sightsavers stories

Catching the urban mosquito: how our research protects communities from NTDs

To tackle disease, we need to know who is affected. In Liberia, Sightsavers has studied mosquitoes and tested children to see how urban migration affects the spread of lymphatic filariasis.