Sunday, April 15, 2007
Distribution of Lymphatic Filiaris in the world
So far I have tended to write about diseases or conditions that have affected either me or someone I know. And this topic is no exception. Well, the condition of Elephantiasis itself did not affect anyone I know, but a friend of mine has a daughter who saw something about the disease on Discovery channel last year and started to worry that she might have it! (My friend and I joke that her daughter is really my blood relative since she has my same tendency to be a hypochondriac!)
Her daughter, who was about 9 or 10 at the time, started focusing on her hands and imagining they were growing. Luckily her mother was finally able to convince her there was nothing wrong with her, and she hasn't had any other health-related panics in recent months! I can so identify with this because it is exactly the kind of thing I used to do...fixate on some symptom and keep checking to see if it was still there.
So, Elephantiasis. It's actually NOT what the famous "Elephant Man" (Joseph Merrick) had. He apparently suffered from something called Proteus Syndrome, not elephantiasis as experts had thought during his lifetime, and not neurofibromatosis, as was postulated in the 1970's.
What is it?
The main type of Elephantiasis, also called Lymphatic Filariasis, is a parasitic disease that is endemic in 80 countries throughout the world, and about 120 million people are directly affected. The disease flourishes in tropical and subtropical areas, including India, Africa, South Asia, the Pacific and the Americas.
Caused by tiny threadlike worms called Wuchereria bancrofti and Brugia malayi that invade the human lymphatic system (the system of lymph nodes and fluid that are the main system for the body to defend itself against disease), Elephantiasis causes enlargement of the leg, arm, genitals, vulva and breasts. The worms live for 4-6 years and produce millions of larvae that are released into the blood. Mosquitoes that bite an infected person pick up the larvae from the blood and are then able to transmit them to another person after the larvae continue to incubate for 1-3 weeks within the mosquito.
The disease has been increasing in prevalence in recent years due to the unplanned growth of cities in the developing world. The cities provide even more places for the mosquitoes to breed and multiply.
Men are more likely to be affected than women; 10-50% of men in affected populations can be symptomatic, and up to 10% of women.
The parasitic form of the disease is not the only type. Since the enlargement of certain body parts is because of swelling due to a build-up of fluid from a blocked lymphatic system, there can be other causes as well.
Nonfilarial elephantiasis, the second type of elephantiasis, is more common in Africa’s central mountains. It is caused by contact with volcanic ash in the soil; since the population mainly goes barefoot, the chemicals from the soil leach into their feet and eventually irritate and block the lymphatic vessels.
Hereditary lymphedema is a disorder caused by a genetic defect, which causes an accumulation of fluid to collect in the affected parts of the body. Underdevelopment of the lymph vessels is thought to be the cause.
What are the symptoms?
The obstruction of the lymphatic vessels results in extreme swelling of the skin and tissues, typically in the lower trunk and body. It primarily affects the legs and genitals, resulting in baggy, thickened and ulcerated skin, along with fever and chills. One serious complication of elephantiasis can also be obstructed blood vessels, which limit blood supply and cause the skin to become infected and can even lead to gangrene.
In the parasitic form of the disease, symptoms of elephantiasis may not appear until years after infection. As the parasites build up in the blood vessels, they restrict circulation and cause fluid to accumulate in surrounding tissues.
Symptoms of infection with elephantiasis are:
Pain in/above testicles (for men only of course)
Enlarged groin lymph nodes
Massively swollen legs, genitalia and breasts
White urinary discharge
How is it diagnosed?
Until recently it was hard to definitively diagnose the parasitic form of the disease. The worms' active period is at night so blood samples taken during the day did not always show any activity. Now, however, there is a simple test that looks for the antigens to the parasites in the blood rather than the parasites themselves, and it is able to be diagnosed with a finger-prick blood test.
How is it treated?
There are medications that remove the parasites from the blood, which helps prevent transmission of the disease. DEC (diethylcarbamazine) reduces the number of parasites from the blood of an infected person for a year; a single dose of two drugs given together (albendazole with DEC or ivermectin) is 99% effective in removing the parasites from the blood for one full year.
Both albendazole and DEC have been shown to be effective in killing the adult-stage filarial parasites (which would accomplish a complete cure of infection), but an ideal treatment protocol has not yet been defined. Eliminating the parasites can help improve the symptoms, especially if the patient is still in the early stages.
Other medications include Suramin, Metrifonate, Mebendazole and Levamisole. Recent studies of use of the antibiotic doxycycline show promise. Medicines must be taken early after the primary infection. The problem with treatment of elephantiasis is that it is difficult to diagnose it early enough for the treatment to prevent the disabling effects of the disease.
Many of the most bothersome symptoms come from secondary bacterial and fungal infections caused by the original infection with the worms. Keeping the affected areas of the body very clean and taking care to minimize infection and encourage lymph flow are important in reducing the frequency of fevers and symptoms of elephantiasis.
Surgery is sometimes used to remove the excess tissue and fluid if possible.
The World Health Organization is working to stop the spread of Elephantiasis by treating the affected populations for the infection and disseminating table salt with DEC in it to keep the level of parasites down.
Control of mosquitoes in the areas where the disease is endemic would also be an important component in eradicating the disease.
Will you get it?
You might if you travel to an area where it is endemic, and newcomers develop symptoms more quickly than populations that have lived with the disease for many years. There is no vaccine currently available. To prevent infection, be sure to wear mosquito repellent and stay covered up wherever mosquitoes are prevalent. If you are in a tropical location sleep with mosquito netting around your bed.
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