FILARIASIS

Filariasis

Filariasis is caused by round, coiled and thread-like parasitic worms belonging to the family filariidae. The disease is caused by the nematode worms, either Wuchereria bancrofti, Brugia malayi or Brugia timori and transmitted by ubiquitous mosquito species Culex quinquefasciatus and Mansonia annulifera/M.uniformis etc. The disease manifests often in bizarre swelling of legs, hydrocele, and swelling of the other dependent parts of the body. Lymphatic Filariasis (LF) is the cause of a great concern and social stigma. Filarial parasites, once deposited on the skin by mosquito, enter the body through the puncture wound created by the mosquito bite and then migrate to the lymphatic system. In India, LF is caused by either Wuchereria bancrofti (99.4%) or Brugia malayi (0.6%).

Bancroftian Filariasis

The lymphatic vessels of legs and other dependent parts including the male and female genitalia are affected in bancroftian Filariasis. In male, it causes episodic funiculitis (inflammation of the spermatic cord), epididymitis and orchitis. Adenolymphangitis of the extremities is less common. Hydrocele is the most common sign of chronic bancroftian filariasis, followed by lymphoedema, elephantiasis and chyluria. The swelling involves the whole leg, the whole arm, the scrotum, the vulva or the breast. The fluid of hydrocele and chyluric patients may contain microfilariae, even when they are absent from the blood. Chyluria becomes more noticeable after a heavy meal. It is often symptomless, but some patients complain of fatigue and weight loss, resulting from loss of fat and protein.

Brugian Filariasis

Lymphadenitis (swollen and painful lymphnode) occurs episodically, most commonly affecting one inguinal lymph node at a time. The infection lasts for several days and usually heals spontaneously. The frequency of episodes may vary from 1-2 attacks per year to several attacks per month. Sometimes, lymphadenitis is followed by a characteristic retrograde lymphangitis. The infection may spread to the surrounding tissues, and occasionally involves the whole thigh or entire limb. In Brugian Filariasis, the infected lymph nodes may develop abscesses, which can ulcerate, and subsequently heal. The acute clinical course with its complications may last from several weeks to 3 months. Characteristically, elephantiasis involves the leg below the knee but occasionally it affects the arm below the elbow. Genital lesions or chyluria (milky color urine) do not occur in brugian filariasis.