Lymphatic Filariasis (commonly known as elephantiasis and abbreviated as LF) is caused by a parasitic thin worm (filarial nematode) that infects humans through mosquito bites. The worms multiply in the body and create blockages within the lymphatic system. This results in fluid collection in various tissues of the body. It leads to massive swelling with severe pain and causes frequent fever from other opportunistic infections arising as a result of these stagnant fluids.
While the infection occurs during childhood, the full impact of this disease shows up during adulthood. In most cases there are no symptoms at all and most people with LF may remain unaware of it. However in a smaller percentage of those affected , lymphedema (swelling) starts occurring several years after they have been infected. This disease causes grotesque disfigurement and disability in affected adults besides other conditions like hydrocele and wheezing. It affects the limbs (arms and legs) and also the genital areas (scrotum, penis). Given the severe enlargement of limbs, they resemble that of an elephant and hence the name elephantiasis. This further decreases the ability of the lymphatic system to fight other infections and opportunistic skin infections occur leading to hardening of skin. It is an irreversible condition at this advanced stage.
Those that live in tropical and sub-tropical areas are susceptible to this disease.
Travellers visiting tropical areas are at a risk.
Mosquito bites are the only vectors for this infection, so avoiding mosquito bites is of utmost importance. Some popular methods that can work are:
- Using mosquito nets while sleeping
- Using mosquito repellent on naked skin
- Prevent mosquitoes from breeding by removing stagnant water
- Wearing covered clothing and avoiding open footwear (sandals, chappals)
Microscopic examination of the blood towards identifying ‘active' microfilariae is the most common method. However, it is not as easy as it sounds. Microfilariae are nocturnal in their activity – this means they circulate actively in the blood only at night. Therefore blood collection has to be done during the night time and analysed promptly. There are newer serological techniques that can better microscopic examination. Despite this, it is quite difficult to diagnose and lab tests often return negative results as lymphedema develops several years after the infection.
The primary strategy for treatment is to kill the active worms circulating in the blood and also prevent infected people from transmitting these worms to others. While drugs can kill the worms, there is still risk of lymphedema (swelling) developing. This would require specialized care and the course is to prevent it from deteriorating further. Some basic methods include:
- Regular and careful cleaning and washing of swollen areas with antibacterial soap and water daily
- Keeping the swollen part elevated and moving it to improve lymphic fluid flow
- Usage of anti fungal, anti bacterial creams on wounds if any
- Encourage mobility using compression bandage support, for the swollen limbs
Once the infection is positively confirmed by lab results and the microfilariae are isolated, there are several safe and rapidly acting drugs that are available for treating LF. There are yearly dosages of medicines available. These are called diethylcarbamazine (DEC). They act fast and kill the worms in the blood. It is also important to break the infection transmission chain by keeping at drug therapy for several years without break and also undertaking community drug administration. There is no filariasis vaccine in the world but efforts are on to develop one.
Surgical treatment is typically considered once all medical management techniques have been exhausted. In most severely disabled patients, surgery may be an option. It is particularly useful for male patients with swollen genitals as massive hydroceles can be reduced by surgical cuts and draining the fluid out However, attempting to improve swollen limb mobility is not so successful and could call for multiple operations and also grafting of the skin. Some surgical approaches include:
- Lymphatic bridging procedures
- Drainage into deep lymphatics
- Excisional operation
- Total subcutaneous excision
- Management of filarial hydrocele