Filariasis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Lymphatic Filariasis (Philariasis) is a parasitic and infectious tropical disease, caused by three thread-like parasitic filarial worms called nematode worms, Wuchereria bancrofti, Brugia malayi, and Brugia timori, all transmitted by mosquitoes. It is extremely rare in Western countries. Loa loa is another filarial parasite of humans, transmitted by the deer fly.
Historical Perspective
Lymphatic Filariasis is thought to have affected humans since approximately 1500-4000 years ago and the first documentation of symptoms occurred in the 16th century, when Jan Huygen Linschoten wrote about the disease during the exploration of Goa.
Causes
Lymphatic Filariasis is caused by nematodes (roundworms) that inhabit the lymphatic vessels and lymph nodes of a human host. Wuchereria bancrofti,Brugia malayi and Brugia timori cause lymphatic filariasis.
Epidemiology and Demographics
Filariasis is endemic in tropical regions of Asia, Africa, Central and South America with 120 million people infected. In endemic areas of the world (e.g., Malaipea in Indonesia), up to 54% of the population may have microfilariae in their blood.[1]
Diagnosis
History and Symptoms
The most spectacular symptom of lymphatic filariasis is elephantiasis—thickening of the skin and underlying tissues—which was the first disease discovered to be transmitted by insects. Elephantiasis is caused when the parasites lodge in the lymphatic system. Elephantiasis affects mainly the lower extremities, whereas ears, mucus membranes, and amputation stumps are rarely affected; however, it depends on the species of filaria. W. bancrofti can affect the legs, arms, vulva, breasts, while Brugia timori rarely affects the genitals.
Laboratory and Findings
The diagnosis is made by identifying microfilariae on a Giemsa stained thick blood film. Blood must be drawn at night, since the microfilaria circulate at night, when their vector, the mosquito, is most likely to bite. There are also PCR assays available for making the diagnosis.
Treatment
Medical Therapy
The recommended treatment for patients outside the United States is albendazole (a broad spectrum anthelmintic) combined with ivermectin.[2] A combination of diethylcarbamazine (DEC) and albendazole is also effective. All of these treatments are microfilaricides; they have no effect on the adult worms.
References
- ↑ Aupali T, Ismid IS, Wibowo H; et al. (2006). "Estimation of the prevalence of lymphatic filariasis by a pool screen PCR assay using blood spots collected on filter paper". Tran R Soc Trop Med Hyg. 100 (8): 753&ndash, 9.
- ↑ U.S. Centers for Disease Control, Lymphatic Filariasis Treatment, retrieved 2008-07-17