What is Lymphatic Filariasis

Lymphatic filariasis is an infection caused by a thread-like worm (filarial parasite) that spreads through mosquito bites. If you get bitten by a mosquito that is infected with the parasite, the parasite can pass from the mosquito into your body.

Once it enters the body, the parasite lives in the network of lymph vessels and lymph nodes that runs throughout the body (lymphatic system). The lymphatic system helps balance fluid levels in the body and helps you fight infections.

What are the causes?

This condition is caused by a bite from an infected mosquito. It takes many mosquito bites over a long period of time for a person to become infected with these parasites. When you get bitten, an immature, microscopic form of the worm (microfilariae) can pass through the skin and into the lymphatic system. Microfilariae grow into adults and release millions of microfilariae that travel through the blood. Filarial worms can live in the lymphatic system for years.

If a mosquito bites an infected person, the mosquito can become infected and pass the infection to other people.

What increases the risk?

You are more likely to develop this condition if you live in:

• Asia.
• Africa.
• South America.
• The Western Pacific.
• The Caribbean.

Visiting these areas is not likely to put you at risk.

What are the signs or symptoms?

Symptoms of this condition may not show for many years after being infected with the filarial worm. As the lymphatic system becomes damaged over time, you may develop a type of swelling (lymphedema) or bacterial skin infections that thicken the skin. The combination of thick skin and lymphedema results in a condition called elephantiasis. Severe cases can be disfiguring and uncomfortable. Elephantiasis may affect:

• Legs.
• Arms.
• Breasts.
• Genital areas.

Some people develop an allergic reaction to lymphatic filariasis (pulmonary eosinophilia syndrome). This may cause:

• Coughing.
• Wheezing.
• Trouble breathing.

In some cases, there are no symptoms of lymphatic filariasis.

How is this diagnosed?

This condition may be diagnosed based on:

• Your symptoms.
• Your medical history.
• Whether you have lived in an area where mosquitoes spread the disease.
• A physical exam. This may include a blood test to confirm the diagnosis. Your health care provider may:
  • Check your blood under a microscope to look for microfilariae.
  • Test your blood for antibodies against lymphatic filariasis. Antibodies are proteins that your body makes to protect you from germs and other things that can make you sick.

How is this treated?

This condition may be treated with medicines, including:

• Citrate salt (diethylcarbamazine). This medicine is used to kill the microscopic worms in your blood. It also kills the adult worms, but it does not kill all of them. Diethylcarbamazinecan also prevent the infection from spreading to another person through a mosquito bite.
• Antibiotic medicine to help fight any bacterial infections that you may have.
• Steroids to help reduce inflammation and swelling.

There is no cure for lymphedema once it occurs, but treatment can help to lessen the impact of the infection.

Follow these instructions at home:

Medicines

• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you were prescribed an antibiotic medicine, take it as told by your health care provider. Do not stop taking the antibiotic even if you start to feel better.

General instructions

• Raise (elevate) swollen limbs above the level of your heart while you are sitting or lying down.
• Carefully wash any swollen areas every day with soap and water.
• Exercise swollen limbs as directed by your health care provider.
• Treat cuts or scrapes with antiseptic cream or ointment to prevent infection.
• Keep all follow-up visits as told by your health care provider. This is important.

How is this prevented?

If you live in an area where mosquitoes carry lymphatic filariasis:

• Sleep under a mosquito net.
• Avoid being outside from dusk to dawn. This is when mosquitos are very active.
• Wear long sleeves and pants.
• Use mosquito repellent.

Contact a health care provider if:

• Your symptoms get worse or do not get better.
• You develop a red, swollen, or painful area on your skin.
• You develop a cough.
• You start to have noisy breathing (wheezing).

Get help right away if:

• You have a fever and redness on the skin that is spreading.
• You develop severe shortness of breath.

Summary

• Lymphatic filariasis is an infection caused by a thread-like worm (filarial parasite) that spreads through mosquito bites.
• The parasite lives in the lymphatic system, which helps balance fluid levels in the body and helps fight infections.
• This condition may be treated with medicines that kill the parasite, fight infections, and reduce swelling.
• To prevent lymphatic filariasis, take steps to prevent mosquito bites, such as by wearing long pants and long-sleeved shirts and using mosquito repellent.