Lymphatic filariasis, commonly known as elephantiasis, is a neglected tropical disease. Infection occurs when filarial parasites are transmitted to humans through mosquitoes. Infection is usually acquired in childhood causing hidden damage to the lymphatic system. Lymphatic Filariasis is a parasitic infection in the blood. Enlargement (lymphedema) of the arms and legs are common among Filipinos. Aside from the lymphedema of the upper or lower extremities, enlargement of the breast of women and enlargement of the scrotum for males.
The painful and profoundly disfiguring visible manifestations of the disease, lymphedema, elephantiasis and scrotal swelling occur later in life and lead to permanent disability. These patients are not only physically disabled, but suffer mental, social and financial losses contributing to stigma and poverty.
Currently, 1.23 billion people in 58 countries are living in areas where lymphatic filariasis is transmitted and are at risk of being infected. Approximately 80% of these people are living in the following 10 countries: Bangladesh, Côte d’Ivoire, Democratic Republic of Congo, India, Indonesia, Myanmar, Nigeria, Nepal, Philippines and the United Republic of Tanzania.
Lymphatic Filariasis is also known as elephantiasis or “tibak” in the local language. Three million (3M) Filipinos are at risk of getting the disease. To date, 44 provinces from the 80 provinces in the Philippines are endemic of elephantiasis.
As of 2011, nine (9) provinces have eliminated lymphatic filariasis namely, Agusan del Sur, Biliran, Bukidnon, Compostela Valley, Cotabato Province, Dinagat Island, Romblon, Sorsogon and Southern Leyte.
Cause and Transmission
Lymphatic filariasis is caused by infection with parasites classified as nematodes (roundworms) of the family Filariodidea.
Adult worms lodge in the lymphatic system and disrupt the immune system. The worms can live for an average of 6-8 years and, during their life time, produce millions of microfilariae (immature larvae) that circulate in the blood.
Lymphatic filariasis infection involves asymptomatic, acute, and chronic conditions. The majority of infections are asymptomatic, showing no external signs of infection. These asymptomatic infections still cause damage to the lymphatic system and the kidneys as well as alter the body’s immune system.
Acute episodes of local inflammation involving skin, lymph nodes and lymphatic vessels often accompany the chronic lymphedema or elephantiasis. Some of these episodes are caused by the body's immune response to the parasite. However most are the result of bacterial skin infection where normal defences have been partially lost due to underlying lymphatic damage.
When lymphatic filariasis develops into chronic conditions, it leads to lymphedema (tissue swelling) or elephantiasis (skin/tissue thickening) of limbs and hydrocele (scrotal swelling). Involvement of breasts and genital organs is common.
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.
Prevention & Control
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
“It does not kill you...
it destroys your appearance, makes you ugly, disfiguring. And therefore there is corresponding Social and Economic impact.”
- Dr. Vicente Belizario
Professor of Parasitology of UP College of Public health