Filariasis

Definition

A group of parasitic diseases caused by infection with filarial nematodes (superfamily Filarioidea), transmitted to humans and other vertebrates through the bite of blood-feeding arthropod vectors. The adult worms inhabit lymphatic vessels, subcutaneous tissues, or body cavities, producing microfilariae that circulate in blood or skin and are ingested by vectors to complete the life cycle. Major forms include lymphatic filariasis (Wuchereria bancrofti, Brugia spp.), onchocerciasis (river blindness, Onchocerca volvulus), and loiasis (Loa loa).

Etymology

From New Latin Filaria (genus name, from Latin filum 'thread') + -iasis (disease condition)

Example

In lymphatic filariasis, Culex quinquefasciatus mosquitoes ingest Wuchereria bancrofti microfilariae during nocturnal blood-feeding; the parasites develop into infective L3 larvae over 10–14 days before transmission to a new human host.

Synonyms

• filarial infection
• filarial disease

Related Terms

• vector-borne disease
• Nematode
• microfilaria
• Onchocerciasis
• Elephantiasis
• neglected tropical disease
• Culex
• Anopheles
• Simulium

Usage Notes

Often used specifically for lymphatic filariasis in public health contexts, though technically encompasses all filarial nematode infections. Distinguished from onchocerciasis and loiasis by vector (mosquitoes vs. black flies or Chrysops deer flies) and clinical presentation. 'Filariasis' without modifier usually implies W. bancrofti or Brugia infection in endemic regions.