What is lymphatic filariasis (LF)?

Lymphatic filariasis (LF), commonly known as elephantiasis, is a disfiguring, disabling disease, usually acquired in childhood. In the early stages, there are no symptoms.  Although there are no outward symptoms, the lymphatic system is damaged. This stage can last for several years.  Infected persons sustain the transmission of the disease.

The long term physical consequences are painful, swollen limbs (lymphoedema or elephantiasis). Everyday work becomes difficult due to frequent infections.  Hydrocele in males is also common in endemic areas.

How is Lymphatic Filariasis transmitted from one person to another?

The adult produces millions of very small, immature larvae known as microfilariae, which circulate in the peripheral blood with marked nocturnal periodicity. The worms usually live and produce microfilariae for 4-6 years.

Lymphatic filariasis is transmitted through mosquito bites. The microfilariae enter the body of a mosquito when it feeds on the blood of a person carrying microfilariae in their blood (mf carriers). It takes 7-21 days for the microfilariae to develop inside the body of the mosquito. 

Who is at risk for infection?

Many mosquito bites over several months to years are needed to get lymphatic filariasis. People living for a long time in filaria endemic areas where the disease is common are at the greatest risk for infection. Short-term tourists have a very low risk. The infection can be detected by night blood survey.

What are the symptoms of lymphatic filariasis?

At first, most people do not know they have lymphatic filariasis. They usually do not feel any symptoms until after the adult worms die. The disease usually is not life threatening, but it can permanently damage the lymph system and kidneys. Because the lymph system does not work right, fluid collects and causes swelling in the arms, breasts and legs. The name for this swelling is lymphoedema. For men, the genital area also becomes swollen, a condition known as hydrocele. The entire leg, arm, or genital area may swell to several times its normal size. Also, the swelling and the decreased function of the lymph system make it difficult for the body to fight germs and infections. These people will have more bacterial infections in the skin and lymph system. This causes hardening and thickening of the skin, which is called elephantiasis.

What is the impact of this disease?

Lymphatic filariasis is a leading cause of permanent and long-term disability worldwide. People with the disease can suffer pain, disfigurement, and sexual disability. Many women with visible signs of the disease will never marry, or their spouses and families will reject them. Affected people frequently are unable to work because of their disability. This hurts their families and their communities.

How can I prevent infection?

Prevention includes giving entire communities medicine that kills the microscopic worms and controlling mosquitoes. Avoiding mosquito bites is another form of prevention. The mosquitoes that transmit the filarial worms usually bite between the hours of dusk and dawn. If you live in an area with lymphatic filariasis take the following precaution:

• Sleep under a mosquito net/insecticide treated mosquito net.
• Use mosquito repellent on exposed skin between dusk and dawn.

What is the treatment for lymphatic filariasis?

People infected with adult worms can take a yearly dose of medicine (DEC) that kills the circulating microfilariae in the blood. While this does not kill all the adult worms, it does prevent infected people from giving the disease to someone else. Even after the adult worms die, lymphoedema can develop. To prevent lymphoedema from getting worse by following several basic principles:

• Carefully wash the swollen area with soap and water every day.
• Use anti-bacterial cream on any wound. This stops bacterial infections.
• Elevate and exercise the swollen arm or leg to move the fluid and improve the lymph flow.