Filariasis is a parasitic disease caused by thread-like worms transmitted to humans through mosquito bites. The infection primarily affects the lymphatic system, which is responsible for maintaining fluid balance and immune function in the body. The signs of filariasis can be divided into early (acute) and late (chronic) stages, reflecting the progression of the disease.
In the early stage, people may experience fever, chills, and general malaise. This is often accompanied by inflammation of the lymphatic vessels (lymphangitis) and lymph nodes (lymphadenitis), causing painful swelling and tenderness in the affected areas. The limbs, especially the legs, as well as the scrotum in men and sometimes the breasts in women, are commonly involved. The skin over these areas may become red, warm, and tender during acute attacks. These episodes can be recurrent and debilitating, often accompanied by systemic symptoms like fever and fatigue.
As the disease progresses to the chronic stage, the most striking sign is persistent swelling due to lymphatic obstruction. This swelling, known as lymphedema, usually starts as soft and pitting but gradually becomes firm and non-pitting as fibrosis sets in. Over time, the affected limbs or genitalia enlarge significantly, sometimes to grotesque proportions, a condition commonly referred to as elephantiasis. The skin thickens, hardens, and may develop a rough, warty texture with folds and cracks. In men, the scrotum can become massively enlarged and deformed, a condition called scrotal elephantiasis.
Other chronic signs include:
– Skin changes such as hyperpigmentation, hyperkeratosis (thickening of the outer skin layer), and papillomatosis (small wart-like growths).
– Formation of nodules or lumps under the skin due to lymphatic vessel dilation.
– Recurrent bacterial infections of the skin and soft tissues, which worsen swelling and cause painful episodes known as acute dermatolymphangioadenitis.
– Restricted mobility and disability due to the size and weight of swollen limbs.
– Psychological and social consequences stemming from disfigurement and stigma.
In some cases, filariasis may cause hydrocele, which is the accumulation of fluid around the testicles, leading to swelling and discomfort.
Early symptoms like itching or tingling sensations in the limbs may also occur before visible swelling develops. The disease can remain asymptomatic for years, with microfilariae (the larval stage of the worms) circulating in the blood without causing obvious signs, making early detection challenging.
Overall, the signs of filariasis reflect the damage caused by the worms to the lymphatic system, leading to impaired drainage of lymph fluid, chronic inflammation, and tissue changes that result in swelling, skin alterations, and secondary infections. Recognizing these signs early is crucial for timely treatment and prevention of severe disability.
