Filariasis 2003

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  • Dr. Bambang SN, Sp.PDInternis RSUD Dr. Soedarso Pontianak

  • GENERAL CONSIDERATIONSMore than 130 million people are infected with lymphatic filariasis ( tropical and subtropical countries). The disease is caused by three filarial nematodes: Wuchereria bancrofti Brugia maLayi, and Brugia timori. W. bancrofti is widely distributed in the tropics ,transmitted by Culex, Aedes, and Anopheles mosquitoes.


    B malayi is transmitted by Mansonia and Anopheles mosquitoes of South India, Sri Lanka, Southeast Asia, South China, the northern coastal areas of China, and South Korea. B timori is found on the southeastern islands of Indonesia.

  • GENERAL CONSIDERATIONSNo animal reservoir hosts are known for W bancrofti or B timori.Cats, monkeys, and other animals may harbor B malayi. Mosquitoes become infected by ingesting microfilariae with a blood meal, they can infect new susceptible hostsOver months, adult worms mature in or near superficial and deep lymphatics and lymph nodes and produce large numbers of circulating microfilariae, which may be seen in the blood starting 612 months after infection.

  • SYMPTOMS AND SIGNSThe incubation period is generally 816 months . Many infections remain asymptomatic.Acute disease Episodes of fever (filarial fever) with or without inflammation of lymphatics and nodes.

  • SYMPTOMS AND SIGNSWith disease progression epididymitis and orchitis as well involvement of pelvic, abdominal, or retroperitoneal lymphatics . Lymph node enlargement may persist. In travelers, allergic. like findings ( rashes, eosinophilia) and lymphangitis and lymphadenitis are more likely to be present. Chronic diseaseObstructive phenomena occur as a result of interference with normal lymphatic flow this includes hvdrocele,

  • SYMPTOMS AND SIGNSscrotal lymphedema, lymphatic varices and eiephantiasis particularly of the tremities. genitals. and breasts. Chyluria may result from rupture of dis:cnded lymphatics into the urinary tract. Manifestations seen in some patients include lymphadenopathy or moderate hepatomegaly or splenomegaly. Occult diseaseA small proportion of infected persons develop ocult disease, in which the classic clinical manifestations and microfilaremia are not present but microfilariac are present in the tissues

  • LABORATORY FINDINGS Diagnosis of active infection is made by finding microfilariae in blood (or hydrocele fluid), a positive antigen test (only, available for W bancrofti) . Microfilariae are rare in the first 23 years. In persons from nonendemic areas, inflammatory reaction maybe prominent in the absence of microfilariae. Microfilariae of W bancrofti are found in the blood at night nocturnal periodicity 10 pm to 2 am .

  • LABORATORY FINDINGS Microfllariae are usually nocturnally periodic but in Southeast Asia may be present at all times. Anticoagulated blood speciments are collected at times related to the periodicity of the local strain. Specimens may be stored at ambient temperatures until examined in the morning by wet film for motile larvae and by Giemsa-stained smears thick for sensitivity and thin for spectfic morphology.

  • TREATMENT DiethylcarbamazineDiethylcarbamazine rapidly kills blood microfilariae . Cure may require multiple 12- day courses (2 mg/kg three times a day after meals, starting with small doses, and gradually increasing over 34 days). At this dose, the drug rarely produces direct toxicity. However, adverse immunologic reactions to dying microfilariae and adult worms are commonmore so with brugian than with bancroftian filariasis. Reactions are local (lymphadenitis, abscess, ulceration)

  • DRUG TREATMENT Reaction are local (lymphadenitis,abscess,ulceration )and systemic (fever, headache, myalgia, dizziness, malaise, and other allergic responses). Antipyrerics and analgesics may be helpful. Albendazole plus Ivermectin can be used.

  • DRUG TREATMENT IvermectinEffective only as a microfilaricide, it is given as a single 200-mg/kg bw dose and repeated in 6 months. Diethylcarbamazine must also be given in order to kill the adult worms. AlbendazoleWhen used as a microfilaricide, it is given at a dosage of 400 mg. For effective macrofilaricidal action, 400 mg is given twice daily for 3 eeks.This drug is free of significant side effects but is generally contraindicated in pregnancy.