Filariasis is a parasitic infection caused by various species of filarial nematodes, which are transmitted to humans by blood-feeding arthropods. Filariasis is a parasitic disease caused by an infection with roundworms of the Filarioidea type. These are spread by blood-feeding insects such as black flies and mosquitoes. They belong to the group of diseases called helminthiases.
These parasites exist in the wild in subtropical parts of southern Asia, Africa, the South Pacific, and parts of South America. One does not acquire them in temperate areas like Europe or the US.
Eight known filarial worms have humans as definitive hosts. These are divided into three groups according to the part of the body they affect:
- Lymphatic filariasis is caused by the worms Wuchereria bancrofti, Brugia malayi, and Brugia timori. These worms occupy the lymphatic system, including the lymph nodes; in chronic cases, these worms lead to the syndrome known colloquially as “elephantiasis.”
- Onchocerciasis is caused by Onchocerca volvulus and leads to intense itching and skin and eye damage.
- Loaiasis is caused by Loa loa and leads to severe swelling under the skin; it is also known as “Calabar swellings.”
All these diseases are acquired through mosquito bites; there is no risk of acquiring filariasis through casual contact with an infected individual. Treatment for filariasis focuses on killing adult worms; this can be done through medication or surgery. In addition, measures should be taken to prevent mosquito bites, as this is the only way to acquire filariasis.