Lymphatic Filariasis (LF) is commonly known as elephantiasis. It is a disfiguring and disabling disease, which is generally acquired in childhood. In the early stages, though there are no symptoms or non-specific symptoms, the lymphatic system is damaged. This stage can last for several years. Infected persons sustain the transmission of the disease. The long-term physical consequence includes painfully swollen limbs (lymphoedema or elephantiasis). Hydrocele in males is also common in endemic areas.
Filariasis is a tropical disease that affects more than 120 million people worldwide. It is a disease caused by mosquitoes, and it infects the body through tiny filarial worms. It is an endemic that has spread to approximately 81 countries across the world, mainly in countries like India and Africa. Other areas include America, South East Asia and the Pacific Islands with migration connections to Australia.
In communities where Elephantiasis is transmitted, all ages are affected. While the infection may be acquired during childhood, its visible manifestations may occur later in life, causing temporary or permanent disability. In endemic countries, lymphatic filariasis has a major social and economic impact with an estimated annual loss of $1 billion and impairing economic activity up to 88%.
The disease is caused by three species of thread-like nematode worms, known as filariae – Wuchereria bancrofti, Brugia Malayi, and Brugia Timori. Male worms are about 3–4 centimeters in length, and female worms 8–10 centimeters. The male and female worms together form “nests” in the human lymphatic system i.e. the network of nodes and vessels that maintain the delicate fluid balance between blood and body tissues. The lymphatic system is an essential component of the body’s immune system.
Filarial infection can cause a variety of clinical manifestations, including lymphoedema of the limbs, genital disease (hydrocele, chylocele, and swelling of the scrotum and penis), and recurrent acute attacks, which are extremely painful and are accompanied by fever. The vast majority of infected people are asymptomatic, but virtually all of them have subclinical lymphatic damage, and as many as 40% have kidney damage, with proteinuria and haematuria.
Self-diagnosis: Elephantiasis can be observed when swelling is noticed. Not only will those body parts begin to look bulky and lumpy with stiff, tough skin, one will also experience a pain in the swollen area. This may be accompanied by chills and fever.
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How Does Filariasis Affect Your Body?
When an infected mosquito bites a healthy person, the larvae called microfilariae move into the lymphatics and lymph nodes. Here, they develop into adult worms and may persist for years. The adult parasite, in turn, produces more microfilariae. These microfilariae circulate in the peripheral blood usually in the night, and are sucked by the mosquitoes during a bite. The same cycle is then repeated in another healthy individual.
What Are The Causes of Filariasis?
Most cases of filariasis are caused by the parasite known as Wuchereria bancrofti. Culex, Aedes and Anopheles mosquitoes serve as a vector for Wuchereria bancrofti in the transmission of the disease. Another parasite called Brugia Malayi, also causes filariasis, and is transmitted by the vector Mansonia and Anopheles mosquitoes.
Mosquitos administer filarial parasites into the human body with recurring bites. These larvae worms reside in the human lymph system where they grow to become adults and live in the body for somewhere between 6-8 years, mating and giving birth to millions of larvae.
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What Are The Risk Factors of Filariasis?
Common risk factors of filariasis:
- People living in tropical and sub-tropical areas
- Travelers visiting tropical areas
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What Are The Symptoms of Filariasis?
- The most common symptom of elephantiasis is swelling of body parts. The swelling mainly happens in the legs, genitals, breasts, and arms.
- The swelling and enlargement of body parts can lead to pain and mobility issues.
- The skin is also affected and may become dry, thick, ulcerated, darker than normal, or pitted.
- Some additional symptoms, such as fever and chills, are also seen in some cases.
- Elephantiasis affects the immune system. Thus, people with this condition are at an increased risk for a secondary infection.
- Lymphatic filariasis infection involves asymptomatic, acute, and chronic conditions. The majority of infections are asymptomatic and show no external signs of infection. However, their blood is positive for microfilaria. This stage may last for months.
How is Filariasis Diagnosed?
Common diagnostic methods used are:
Blood sample – The microfilariae that cause lymphatic filariasis circulate in the blood at night (called nocturnal periodicity). Blood collection should be done at night to coincide with the appearance of the microfilariae, and a thick smear should be made and stained with Giemsa or hematoxylin, and eosin. For increased sensitivity, concentration techniques can be used.
Serological examination – Serologic techniques provide an alternative to microscopic detection of microfilariae for the diagnosis of lymphatic filariasis. Patients with an active filarial infection, typically have elevated levels of antifilarial IgG4 in the blood, and these can be detected using routine assays.
How to Prevent And Control Filariasis?
Currently, there are no vaccines available, so preventing mosquito bite is the best form of defense. This can be achieved by:
- Refraining from going outdoors during dusk or dawn, when the carriers are highly active
- Sleeping inside an insecticide-treated mosquito net
- Wearing long-sleeved shirts and trousers
- Refraining from sporting strong perfume or cologne which can draw the attention of mosquitoes
Treatment of Filariasis
Common methods for treating filariasis are:
- Medication – 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 it 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.
- Surgery – 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) and excisional operation (Total subcutaneous excision).
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Filariasis – Lifestyle Tips
Symptoms of filariasis can be alleviated by:
- Carefully wash the swollen area with soap.
- Use anti-bacterial anti-fungal creams on the wound.
- Elevate and exercise the swollen arm or leg to move the retained fluid and improve lymph flow. Use compression bandages to reduce accumulation of fluid in the legs.
What Are The Recommended Exercises For a Person With Filariasis?
No clinical data is available for this.
Filariasis And Pregnancy – Things to Know
Similar to other helminth infections, lymphatic filariasis has been shown to have prominent symptoms in pregnancy, affecting both the mother and the developing fetus. In lymphatic filariasis, microfilariae invade regional lymph nodes in the pelvis, causing local inflammation. The severe inflammation can result in genital deformities of the vulva.
Chronic infection leads to distortion of anatomy as well as secondary bacterial infections. This can be socially devastating for the mother. Furthermore, it has been postulated that infants born to mothers with filariasis during pregnancy can have hyporesponsiveness to infections in the future as an infant or child.
Common Complications Related to Filariasis
The most common complication of elephantiasis is disability caused by extreme swelling and enlargement of body parts. The pain and swelling can make it difficult to complete daily tasks or work. In addition, secondary infections are a common concern with elephantiasis.
Q. Can filariasis be sexually transmitted?
A. The majority of cases are due to filariasis; however, a small but significant proportion of patients develop genital elephantiasis due to bacterial sexually transmitted infections (STIs), mainly lymphogranuloma venereum (LGV) and donovanosis.
Q. Is filariasis contagious?
A. The disease spreads from person to person through mosquito bites. People get lymphatic filariasis from the bite of an infected mosquito. The microscopic worms pass from the mosquito through the skin and travel to the lymph vessels.