Filariasis (patient information)
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Filariasis |
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Filariasis On the Web |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Ahmed Elsaiey, MBBCH [2]
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Overview
Filariasis is a parasitic disease caused by microscopic, thread-like worms. The adult worms only live in the human lymph system. The lymph system maintains the body's fluid balance and fights infections. Filariasis affects over 120 million people in 73 countries throughout the tropics and sub-tropics of Asia, Africa, the Western Pacific, and parts of the Caribbean and South America. You cannot get infected with the worms in the United States.
What are the symptoms of Filariasis?
- It can be asymptomatic.
- Elephantiasis (frequently in the lower extremities)
- Scrotal swelling
- Cough
- Fever
- Malaise
- Headache
- Chills
- Subcutaneous lumps
- Itching
- Inflammation of the lymphatics
What causes Filariasis?
Filariasis is caused by parasitic organisms called nematodes or round worms. They include:
- Brugia malayi
- Brugia timori
- Loa loa
- Mansonella ozzardi
- Mansonella perstans
- Mansonella streptocerca
- Onchocerca volvulus
- Wuchereria bancrofti
Who is at highest risk?
- Repeated mosquito bites over several months to years are needed to get lymphatic filariasis.
- People living for a long time in tropical or sub-tropical areas where the disease is common are at the greatest risk for infection.
When to seek urgent medical care?
- You should seek medical care when you experience the symptoms of the filariasis as:
- Filarial fever
- Elephantiasis
- Scrotal swelling
- Subcutaneous lumps
Diagnosis
The standard method for diagnosing active infection is the identification of microfilariae by microscopic examination. This is not always feasible because in most parts of the world, microfilariae are nocturnally periodic, which means that they only circulate in the blood at night. For this reason, the blood collection has to be done at night to coincide with the appearance of the microfilariae.
Serologic techniques provide an alternative to microscopic detection of microfilariae for the diagnosis of lymphatic filariasis. Because lymphedema may develop many years after infection, lab tests are often negative with these patients.
Treatment options
People infected with adult worms can take a yearly dose of medicine, called diethylcarbamazine (DEC), that kills the microscopic worms circulating in the blood. While this drug does not kill all of the adult worms, it does prevent infected people from giving the disease to someone else. Lymphedema and elephantiasis are not indications for DEC treatment because most people with lymphedema are not actively infected with the filarial parasite. Physicians can obtain DEC from CDC after lab results confirm infection. Even after the adult worms die, lymphedema can develop. You can ask your physician for a referral to see a lymphedema therapist for specialized care. Prevent the lymphedema from getting worse by following several basic principles:
- Carefully wash the swollen area with soap and water every day.
- Elevate and exercise the swollen arm or leg to move the fluid and improve the lymph flow.
- Disinfect any wounds. Use antibacterial or antifungal cream if necessary.
What to expect (Outlook/Prognosis)?
- Early cases has good prognosis.
- Disease can leave an individual severely disabled with genital damage or elephantiasis.
Possible complications
- Lymphedema
- Hydrocele
- Renal impairment
Prevention
Avoiding mosquito bites is the best form of prevention. The mosquitoes that carry the microscopic worms usually bite between the hours of dusk and dawn. If you live in or travel to an area with lymphatic filariasis:
- Sleep under a mosquito net.
- Wear long sleeves and trousers.
- Use mosquito repellent on exposed skin between dusk and dawn.
Videos
Filariasis in British Guinea: {{#ev:youtube|JniCQhkvaNg}}
Sources
- http://www.nlm.nih.gov/medlineplus/
- https://www.cdc.gov/parasites/lymphaticfilariasis/gen_info/faqs.html