Filariasis

Filariasis is an infectious parasitic disease caused by thread-like nematode worms (filariae) transmitted to humans through the bites of infected mosquitoes or other arthropod vectors. The three main types are lymphatic filariasis (caused by Wuchereria bancrofti, Brugia malayi, or Brugia timori), subcutaneous filariasis (caused by Loa loa or Mansonella streptocerca), and serous cavity filariasis (caused by Mansonella perstans or Mansonella ozzardi). Lymphatic filariasis, the most common and clinically significant form, is also known as elephantiasis when it progresses to its severe chronic stage. The disease primarily affects the lymphatic system, leading to lymphatic dysfunction, chronic lymphedema, and in advanced cases, massive swelling of the limbs, genitalia (hydrocele), and breasts — a condition known as elephantiasis. Subcutaneous filariasis can cause skin swelling (Calabar swellings), eye involvement (eye worm in Loa loa infection), and dermatitis. Many infected individuals remain asymptomatic but may harbor microfilariae in their blood, contributing to ongoing transmission. Acute episodes of adenolymphangitis (inflammation of lymph nodes and vessels) with fever, pain, and swelling are common recurrent manifestations. Treatment depends on the specific filarial species involved. Diethylcarbamazine (DEC) is the primary drug for lymphatic filariasis and Loa loa infections, killing both microfilariae and some adult worms. Ivermectin is effective against microfilariae and is used in mass drug administration programs, often in combination with DEC or albendazole. Doxycycline, which targets the Wolbachia endosymbiont bacteria essential for filarial worm survival, has shown efficacy in killing adult worms and is increasingly used as an adjunctive therapy. The World Health Organization has implemented global elimination programs based on mass drug administration. Surgical intervention may be required for advanced lymphedema or hydrocele. Supportive care including limb hygiene, compression, and elevation helps manage chronic lymphedema.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Filariasis