Elephantiasis Filariasis

What is Elephantiasis?

Elephantiasis is the common name for a disease called, filariasis.  This is a parasitic disease caused by infection by any one of three different species of parasitic worms: Wuchereria bancrofti, Brugia malayi, and Brugia timori. The disease occurs when the worms grow in the lymphatic vessels of the infected person causing blockage of those vessels so that fluid from tissues cannot drain.  Swelling and damage to the lymph glands occurs.  In the late stage, extreme and painful swelling of the legs and genitals is known as elephantiasis.

How do you get Elephantiasis?

The worms that cause filariasis are acquired through the bite of an infected mosquito.  The worms then grow in the lymphatic vessels of the infected person. Lymphatic vessels function to drain fluid from tissues throughout the body. Inflammation caused by the worms that block the lymphatic vessels, causes painful swelling and damage to the lymph glands over time.

Susceptibility and Resistance

Humans are universally susceptible to filariasis, and repeated infections may occur in regions where filariasis is common. 

Incubation Period

The incubation period for Elephantiasis is 90-365 days.

What are the Symptoms?

Initially, most filariasis infections do not show symptoms at all. However, the adult living worms reside in the lymphatics of the infected individual and can cause progressive lymphatic damage. The blockage in the lymphatic vessels can cause painful swelling in the legs, arms, breasts, and genitals. Secondary bacterial infections in the lymph nodes and channels can also occur and worsen this swelling. 

Other symptoms include: high fever, milky white urine, tropical pulmonary eosinophilia (which is a serious condition manifested by nocturnal wheezing and coughing), progressive and chronic lung disease, and recurrent low-grade fever.  

Preventative Measures

There are no vaccines or drugs to prevent filariasis.  The best way to avoid this disease is to avoid mosquito bites.  The mosquitoes that carry the worms usually bite between dusk and dawn.  To avoid mosquito bites in an area where this disease occurs, sleep in air conditioned rooms or under mosquito nets.  Between dusk and dawn, wear long sleeves and trousers, and use mosquito repellent on exposed skin.


Treatment with the anti-parasitic drug Diethylcarbamazine citrate (DEC) is generally used to treat filariasis and is effective at killing both adult worms and circulating larva. Ivermectin and albendazole are also used in combination to rapidly suppress the larva circulating in the blood, but these drugs may not kill all adult worms. 

Anti-parasitic drug treatment is usually repeated annually as low levels of the larva may reappear after treatment with any drug. 

When an individual has an infection, supportive measures include elevation of swollen limbs, exercise, and use of topical anti-fungal or antibiotic medications.  These medications can also help prevent further infection and swelling.

Surgery may be necessary to reduce the pressure on organs or body parts from the swelling. 


Where Does It Commonly Occur?

Filariasis infections occur in tropical and subtropical regions of Asia (Bangladesh, Cambodia, India, Indonesia, Laos, Malaysia, Maldives, the Philippines, Sri Lanka, Thailand, Timor-Leste, and Vietnam), Africa (many countries), Central and South America (Brazil, Costa Rica, Dominican Republic, Guyana, Haiti, Suriname, and Trinidad and Tobago), and the Pacific Islands (American Samoa, the Cook Islands, Fiji, French Polynesia, Micronesia, Niue, Samoa, Tonga, Tuvalu, Papua New Guinea, and Vanuatu). In the Middle East, it is present only in Yemen.