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.
What is name of the drug given during MDA?

DEC (Diethylcarbamazine citrate tablets).

Who should take the medicine?

Everyone living in filaria endemic area above two year age, except pregnant women & seriously ill person.

How often one should take DEC tablets?

Once a year during Mass Drug Administration.

How tablets should be taken?

The tablets should be swallowed with water and tablets should not be taken on empty stomach.

How many DEC tablets should be taken during MDA?

DEC tablet should be taken by different age groups as indicated below:

0-2 years Nil
2-5 years 1 tablet of 100 mg.
6-14 years & above 2 tablets of 100 mg. each
15 years & above 3 tablets of 100 mg. each

Where DEC tablets are available?

DEC tablets are available with health workers or volunteers during MDA who will make house to house visits and give tablets. Drug distribution booth is also set up at health facilities and other public places during MDA campaign. These tablets are supplied free.

Is there any side effect from the medicine? Persons harbouring microfilariae in their blood, may experience some mild side effects like bodyache, vomiting, heachache and dizziness or fever, sometimes rash and itchiness may occur. These side effects usually subside within a day. If any symptoms persist, go to health centre for immediate treatment.

Is it safe to take the medicine during sickness?

Yes, DEC can be taken during mild illness.

Is it safe to take the medicine during pregnancy?

No, treatment of pregnant woman with DEC should be delayed until delivery.

Why should healthy persons consume DEC tablets?

Apparently healthy persons may still carry parasites that may lead to symptoms like elephantiasis after a few years and during the symptomless status, one may continue to transmit the infection to others through mosquito bites.

Why the drug is given to the whole village?

DEC kills microfilariae in the blood and the mosquitoes will not be able to transmit the infection if the population in the village take the drug .Therefore the Mass Drug Administration (MDA) with single dose is given annually .Adult female filaria worm lives in body usually for 5-7 years & produce baby filaria (microfilariae),therefore the MDA is implemented for 5-7 years.

We know somebody with a swollen leg who took the drug but no relief was observed?

The drug does not cure the chronic effects of L.F. But there is other simple method to decrease the suffering through hygienic foot care. The health facility will demonstrate the simple techniques of washing the legs & keeping it dry to decrease the sufferings.

What are the benefits of MDA?

The transmission can be eliminated after 5 to 7 round of MDA covering a minimum of 85% population. The onset of the disease can be prevented and the future generations will be free from filariasis?