Elephantiasis
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Image:Elephantiasis.jpgElephantiasis (Greek ελεφαντίασις, from ελέφαντας, "the elphant") is a syndrome that is characterized by the thickening of the skin and underlying tissues, especially in the legs and genitals. Elephantiasis generally results from obstructions of the lymphatic vessels. It is most commonly caused by a parasitic disease known as lymphatic filariasis.
Alternatively, elephantiasis may occur in the absence of parasitic infection. This nonparasitic form of elephantiasis, known as nonfilarial elephantiasis or podoconiosis, generally occurs in the mountains of central Africa. Nonfilarial elephantiasis is thought to be caused by persistent contact with volcanic ash.
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Lymphatic Filariasis
However, lymphatic filariasis is by far the most common cause of elephantiasis. Organisms that cause lymphatic filariasis are Wuchereria bancrofti, Brugia malayi, and Brugia timori, all of which are nematodes (i.e., roundworms) transmitted by mosquitoes. Most patients with lymphatic filariasis are infected with W. bancrofti.
In patients with lymphatic filariasis, the parasite occupies lymph vessels that drain the lower extremities, producing massive enlargement and deformity of the legs and genitalia. However, it is unclear whether the swelling that occurs results from the obstruction of these lymphatic vessels or, alternatively, from the immune response to the parasite and their endosymbiotic bacteria, Wolbachia, which are discussed below.
Lymphatic filariasis currently affects around 120 million people in 80 countries, and 40 million of these people have been seriously infected with the disease. This disease is extremely rare in Western countries and is found almost exclusively in the tropics.
When lymphatic filariasis is caused by infection with Wucheria bancrofti, it may be referred to as bancroftian filariasis. Infection with Brugia malayi results in a syndrome that is virtually identical, while Onchocerca volvulus causes many disorders in addition to elephantiasis.
Elephantiasis should not be confused with Proteus syndrome, a completely different disorder partly responsible for the deformity of the "Elephant Man" Joseph Merrick.
Treatment
Medicines to treat lymphatic filariasis are most effective when used soon after infection, but they do have some toxic side effects. In addition, the disease is difficult to detect early. Therefore, improved treatments and laboratory tests are needed.
Another form of effective treatment involves rigorous cleaning of the affected areas of the body. Several studies have shown that these daily cleaning routines can be an effective way to limit the symptoms of lymphatic filariasis. The effectiveness of these treatments suggests that many of the symptoms of elephantiasis are not directly a result of the lymphatic filariasis but rather the effect of secondary skin infections.
Also, surgical treatment may be helpful for issues related to scrotal elephantiasis and hydrocele. However, surgery is generally ineffective at correcting elephantiasis of the limbs.
A vaccine is not yet available and is unlikely to be developed in the near future.
Antibiotics as a possible treatment
In June 2005, a new study from the Liverpool School of Tropical Medicine reported that common antibiotics such as doxycycline may be effective in treating elephantiasis. The parasites responsible for elephantiasis have a population of symbiotic bacteria, wolbachia, that live inside the worm. When the symbiotic bacteria are killed by the antibiotic, the worms themselves also die.