Filariasis

Imagine having your legs and genital organs puff up to roughly the size of elephant limbs. Now imagine having to attend to your daily activities while attempting to move your huge and swollen body parts. This is a type of disease that actually does happen to people.
Filariasis, also known as lympathic filariasis (LF), is most common in tropical countries and is caused by parasitic nematode worms that look like tiny threads. The infection caused by these filarial worms, Wuchereria bancrofti, Brugia malayi and Brugia timori, are transmitted by mosquitos. Fortunately, this infectious disease is very rare in Western countries.
Lymphatic filariasis has existed for a long time. Reports of the disease have been documented in ancient Greek literature, and its symptoms were first recorded in the 16th century, during early explorations of Goa, Asia and Africa. It was only in later centuries when a better understanding of filariasis was developed, pinpointing mosquitoes are carriers of the worms.
According to the World Health Organization (WHO), as of 2006, there has been an estimated 1.3 billion people in more than 80 countries at risk of contracting LF. At present, there are over 120 million infected individuals, and over 40 million of them have been disfigured and severely debilitated by the disease. Affected people mostly live in India, Africa, South Asia, the Pacific, and South and Central America.
LF is considered the highest among the world’s diseases that cause severe disability and disfiguration. It mostly strikes poor portions of the population in areas where there are great numbers of breeding sites for mosquitoes that carry the disease.
Lymphatic Filariasis starts from the bite of an infected mosquito, or when a person comes into contact with water where infected mosquitoes breed. The parasitic worms that are transferred to humans burrow into the lymphatic system, the body’s network of vessels and nodes which carry lymph fluid to the tissues and blood. The lympathic system forms a major part of our body’s immune system.
Adult worms will live in the lympathic vessels for 4 to 6 years, and the females can produce a large number of larvae (microfilariae) which travel around in the bloodstream. The infection can be spread when a mosquito that has bitten an infested person. The mosquito then becomes a carrier of microfilaria which will develop into an infective parasite and be transmitted once the mosquito bites other people. In the endemic areas where the disease is concentrated, it is estimated that 54% of the population are infected by microfilariae.
Although it is not fatal, filariasis is chronic and very painful. The disease causes an accumulation of fluid (hydrocoele); swelling (lymphoedema) of the subcutaneous layer of the skin which houses fat and connective tissues; passing of cloudy-colored urine (chyluria), and in its most extreme form, the skin and underlying tissues of the lower limbs and scrotum thicken and become distended, taking on the resemblance of elephant limbs and earning it the name, elephantiasis.
The inflammation that starts within the skin is usually caused by the immune system’s reaction to the parasite. It can also be caused by bacteria which may have invaded the skin because of an already weakened immune system. At this point, the lymph nodes and lympathic vessels will also start to swell.
These symptoms develop in a very slow manner, sometimes taking years. Those who are infected do not show any outward signs until the disease reaches its late phase. In the latter stage of the disease, affected persons are immediately identified because of their grossly swollen legs, arms, breasts or genitals with cracked, thickened skin that is rough and hard to the touch. LF can also cause damage to the kidneys and the entire lympathic system. People who are affected by lympathic filariasis are subjected to social stigma and are unable to live a normal life.
In the past, it was very difficult to diagnose filariasis because the parasitic worms could only be detected by looking at blood samples through a microscope. These parasites are also nocturnal, which meant that they only showed up in the blood shortly before or after midnight. Just recently, a simple and very sensitive ICT “card test” was developed that could identify parasite antigens, foreign protein substances from an infection, in just a few drops of blood. This could now be achieved at any time during the day without the need of a laboratory.
Other methods of detecting the presence of lympathic filariasis can be made using a Giemsa stained thick blood film, a test taken at night by examining a drop of blood smeared on a slide, and PCR assays, a sensitive organism-detection method.
Treatment includes medications like ivermectin (Mectizan) and Albendazole, both anti-parasitic drugs. However, the best way to eliminate lympathic filariasis would be to prevent the spread of infection.
In areas where filariasis is endemic (concentrated), treating the whole community involves getting rid of all the parasites in the blood of infected persons. This way, the infection is prevented from spreading. In recent studies, it was found that diethylcarbamazine (DEC), ivermectin and Albendazole combined in single doses can significantly decrease microfilariae in the blood by as much as 99%, and last for 12 months after administering treatment.
While these medications are effective in eliminating adult filarial worms, treatment for late stage elephantiasis and hydrocoele is still in need of improvement. The goal would be to ease the pain and discomfort of swollen body parts. Some treatments include injections of schlerosants to treat fluid accumulation, and surgical procedures to remove excessively swollen tissue. Sometimes a lymphovenous shunt to drain fluid is performed.
To manage existing symptoms, doctors advice a lot of bed rest, wearing elastic bandages or surgical stockings to reduce swelling, wearing comfortable shoes, exercising the swollen limb at regular intervals, raising affected legs at night, and taking antibiotics to prevent bacterial infections. A rigid hygienic regimen is also recommended to prevent further bacterial infection and to stimulate lymph functions. Keeping the affected areas clean can diminish periods of inflammation, also known as “filarial fevers”, and improve the appearance of elephantiasis.
While mild cases are relatively easy to treat, it becomes more difficult if the disease has reached its late stages.
Preventing the occurrence of lympathic filariasis means avoiding the bites of mosquitoes suspected of carrying the disease. The World Health Organization recommends limiting any outdoor activities during nighttime, especially if living in rural areas or jungles; wearing long sleeves and long pants; avoiding dark-colored clothing which is attractive to mosquitoes; not wearing scents like perfume or cologne; treating clothes with an insect repellent like permethrin (Duramon, Permanone); using citronella or lemon eucalyptus leaves to ward off mosquitoes; installing screens and mosquito nets, and using air-conditioning, as cooler air causes mosquitoes to become lethargic.
In a 2007 study by the National Institute of Allergy and Infectious Disease (NIAID), 23,500 people living in Egypt participated in a two-year health assessment program to test the effectiveness of an LF elimination campaign.
While there is no vaccine for LF as of the present, scientists are still working to find a preventive inoculation for the disease. The World Health Organization also continues its drive to stop the infection from spreading, and to ease the symptoms of those already infected. Even global healthcare corporations like SmithKline Beecham, and Merck and Co., Inc. have joined the fight against lympathic filariasis through donation of medicines and supporting the elimination of the disease.