Contributor: Gordon K. Klintworth
Elephantiasis (lymphatic filariasis) is a major international helminth disease that affects ~120 million people. Most cases of this type of filariasis are due to Bancroftian filariasis. This infection by Wucheria bancrofti accounts for >80 million cases. Bancroftian filariasis needs to be differentiated from brugian filariasis that is caused by Brugia malayi or Brugia timori. All types of lymphatic filariasis are transmitted by mosquitoes and the adult worm lives in the lymphatic vessels and obstructs lymphatic flow. The manifestations of these lymphatic forms of filariasis are elephantiasis, chyluria, and hydrocele. The organisms live in different parts of the world. Wucheria bancrofti is endemic in Africa, Asia, the Caribbean Island, Latin America, Western Pacific Islands, and South Pacific Islands. Infection by Brugia malayi occurs in China, Korea, the Philippines, South West India, and Vietnam. Brugia timori has only been recognized in Indonesia. Wucheria bancrofti is transmitted by Aedes, Anopheles., and Culex mosquitoes. The Anopheles and Mansonia genera of mosquitoes transmit Brugia malayi. Anopheles transmits Brugia timori. Diagnosis is established by detecting the microfilariae in the blood. The clinical manifestations of Bancroftian filariasis and brugian filariasis are similar. Most ocular microfilariasis is due to other organisms. Adult worms have been reported in the conjunctiva in brugian filariasis. Intraocular infection is rare, but an adult worm of either Wucheria bancrofti or Brugia species has seen in the subretinal space, iris, anterior chamber, lens capsule, retina, choroid, and lacrimal gland. Elephantiasis of the eyelid is extremely rare.