$Unique_ID{BRK03743} $Pretitle{} $Title{Filariasis} $Subject{Filariasis Wuchereriasis Filarial Elephantiasis Bancroftian Filariasis Filariasis Malayi Filariasis not caused by Wuchereria Bancrofti or Brugia Malayi Tropical Eosinphilia} $Volume{} $Log{} Copyright (C) 1986 National Organization for Rare Disorders, Inc. 116: Filariasis ** IMPORTANT ** It is possible that the main title of the article (Filariasis) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms Wuchereriasis Filarial Elephantiasis DISORDER SUBDIVISIONS Bancroftian Filariasis Filariasis Malayi Filariasis not caused by Wuchereria Bancrofti or Brugia Malayi Tropical Eosinphilia General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section. Filariasis usually refers to disease caused by either the Wuchereria Bancrofti or Brugia Malayi worms and marked by features of lymphadenopathy including inflammation, swelling, and, if untreated and repeatedly reinfected over a long period of time, elephantiasis, especially in the legs and genital regions. Filariasis is common in the Asian and Polynesian tropics. In North America, filariasis is very rare, occurring only in people who have travelled or lived in these areas. The infection is transmitted by several tropical mosquito species, which ingest the larval parasite from one host and subsequently bite and inoculate a new host with it. The larvae, known as microfilariae, make their way to the lymphatics, where they reach their adult stage and begin producing more microfilariae. Disease is primarily a reaction to adult worms, not to the microfilariae. Some cases of filarial infection are asymptomatic. The prognosis is good. Symptoms Symptoms and signs of Filariasis vary with the severity of the infection. The adult worms, lodged in the lymphatics, together with the surrounding inflammation and fibrosis, cause progressive obstruction of the lymph vessels. Symptoms, when present, may include fatigue, a sense of heaviness, general malaise, chills, vertigo, headache, photophobia, vomiting, and limb pain. Other clinical manifestations include swelling and redness of the limbs, inflammation of lymph nodes and vessels, testicles, spermatic cord, and epididymus, varicose lymph vessels, edema, hypertrophy of skin and subcutaneous tissues, the presence of chyle in the urine, and fever. As the obstruction of the lymphatics progresses, edema becomes chronic, and there may be marked enlargement of the scrotum, vulva, legs, and breasts, i.e., elephantiasis. Abscesses or calcifications surrounding adult worms which have died and lost their immunologic "disguise" may develop, particularly in the pelvis, kidneys, or inguinal lymph nodes. Microfilariae can be detected in the tissues, including the skin, which is useful for diagnostic purposes. They also usually are found in the blood. There is moderate eosinophilia. Tropical eosinophilia is a variant of filariasis in which there are hypereosinophilia, high antifilarial antibody titres, and microfilariae in the tissues but not in the blood. Clinical manifestations of this form of filariasis comprise enlargement of the lymph nodes and spleen, and sometimes, chest infiltrates, cough, and bronchospasm. Causes The pathogenic worms which cause Filariasis are Wuchereria Bancrofti in Polynesia, and Brugia Malayi in Asia, including east of the Indian subcontinent. As described previously, mosquitos vector the disease. Symptoms result primarily from inflammatory reactions to the adult worms; possibly, hypersensitive reactions to the microfilaria also develop. Related Disorders The term "filariasis" in this article has been used in its narrower sense. In its broad sense, filariasis refers to a group of parasitic diseases caused by various species of filarial nematodes. Examples of these diseases include acanthocheilonemiasis, mumu, loiasis (Calabar swellings), dirofilariasis (human infection by dog heartworm), and onchocerciasis (river blindness). All of these except dirofilariasis can be acquired only in the tropics, where they are common, but are extremely rare in temperate climates. Therapies: Standard In the tropics, mosquito control is an important part of treatment and prophylaxis. Generally, Filariasis is self limited unless reinfections occur. Thus some cases, especially those imported to temperate regions, where there is no danger of spreading the disease due to the absence of suitable vector mosquitos, may be left untreated. In severe cases, however, treatment may be directed at the elimination of the microfilariae and adult worms. Diethylcarbamazine, the most effective drug in use, removes microfilariae and kills or impairs the reproductive capacity of the adult worms. A somewhat less effective drug, levamisole, has also been investigated. The elimination of adult worms must be undertaken with care because they can provoke dangerous allergic reactions and cause abscess formation when they are dead. These side effects can be controlled by antihistamines or corticosteroids. Adult worms, their remains, or calcifications developing around them, may be removed surgically if necessary. Surgery alleviates elephantiasis of certain structures such as the scrotum. Treatment of elephantiasis of the legs usually consists of elevation and support from elastic stockings. Therapies: Investigational This disease entry is based upon medical information available through September 1989. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Filariasis, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 International Filariasis Association Department of Helminthology London School of Hygiene and Tropical Medicine Heppel Street London WC1 E 7HT England Centers for Disease Control (CDC) 1600 Clifton Road, NE Atlanta, GA 30333 (404) 639-3534 NIH/National Institute of Allergy and Infectious Disease 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5717 References Brown, KR, Phillips, SM. Tropical diseases of importance to the traveler. ADV INTERN MED (1984) 29:59-84. Campbell, WC. Efficacy of the vermectins against filarial parasites: a short review. VET RES COMMUN (1982 May) 5(3):251-62. Goodwin, LG. Recent advances in research on filariasis. Chemotherapy. TRANS R SOC TROP MED HYG (1984) 78 suppl:1-8. Hawking, F. Diethylcarbamazine and new compounds for the treatment of filariasis. ADV PHARMACOL CHEMOTHER (1979) 16:129-94. Miller, M.J. Use of levamisole in parasitic infections. DRUGS (1980 Aug) 20(2):122-30. Spry, CJ, Kumaraswami, V. Tropical eosinophilia. SEMIN HEMATOL (1982 Apr) 19(2):107-15.