Other Filariasis

A dozen filarias can cause illness in man. All have a cycle requiring a vector (Culex, Aedes) and symptoms characteristic of the nature of the adult nematodes and the immune response to the microfilariae. Prophylaxis, requiring massive chemoprophylaxis and treatment of the vectors, is almost impossible.

Lymphangitic filariasis is estimated that there are about 90 million people affected worldwide. It predominates in China, India, Indonesia and tropical Africa. It also occurs in Brazil, Guayana and the islands of the Pacific and Caribbean. In 90% of cases obstruction of the lymphatic vessels is caused by the adult worms of Wuchereria bancrofti and in the other cases by Brugia malayi and B. timori.

Most cases are asymptomatic, without the presence of microfilariae. Acutely there can be adenitis, centrifugal lymphangitis and recurrent fever. Lymphangitis of the genitals is not uncommon. The disease is generally recurrent. Chronic disease is characterized by adenolymphoceles, varicose veins, lymphedema and elephantiasis.

Loasis or filariasis Loa loa affects 13 million people in tropical Africa. It is acquired from Chrysops sp. It is manifested by cutaneous lesions and the immune reaction to destruction of the microfilariae. The incubation period is 4 months to 20 years. It is associated with pruritus of the thorax and genitalia, angioedema, and subcutaneous migration sites (Calabar swellings). Larvae in the skin form palpable, erythematous cords of less than 10 cm and that move 1 cm per minute.

The conjuntivae may be affected. It may be related to a glomerulonephritis.

Dirofilariosis occurs throughout the world and affects man in an accidental manner. It is produced by filariae of the dog Dirofilaria repens, D. immitis and the filaria of the mouse D. tenuis. In the skin adult filariae reside in serous-filled cysts. They are also found in lungs and heart.

Mansonelosis occurs in Asia, Africa and South America and is caused by Man-sonella perstans, M. ozzardi, M. streptocerca and M. rodhaini. It is transmitted by insects of the gender Culicoides and it causes pruritus.

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