Filariasis is a parasitic tropical infectious disease which is caused by a thread like worm belonging to the family of filirioidea.
There are three types of filariasis depending upon the niche within the body that the worms occupy. These are lymphatic filariasis, subcutaneous filariasis and serous cavity filariasis.
The worst form of lymphatic filariasis is elephantiasis, a disease wherein there is edema along with thickening of the skin and underlying tissues.
Lymphatic filariasis is caused by the worms Wuchereria bancrofti, Brugia malayi and Brugia timori. These worms occupy the lymphatic system, including the lymph nodes.
Subcutaneous filariasis is caused by the african guinea eye worm (loa loa). Other worms include mansonella stretocera, onchoserca volvulus and dracunculus medisensis. These worms occupy the subcutaneous layer of the skin i.e. the fat layer.
Serous cavity filariasis is caused by the worms Mansonella perstans and Mansonella ozzardi. These worms occupy the serous cavity of the abdomen.
In all cases, the transmitting vectors are blood sucking insects like a fly or a mosquito. Filariasis is endemic in tropical regions of Asia, Africa and Latin America.
There are no immediate symptoms after filarial infection. It may take years to have acute inflammation due to immune response against the worm.
In the second phase of acute inflammation, there may be fever with chills, skin infections, painful lymph nodes and the skin of the lymph edematous extremities become tender. The symptoms may subside after 5-7 days. There may be inflammation of the testes (orchitis) and spermatic cord (epididymitis).
In the third obstructive phase there are lymph varices, lymph scrotum, hydrocele, lymph in urine (chyluria) and elephantiasis.
In the last phase there is the development of scars on the affected area.
Gradually the parasite attacks the lymphatic system and there is a thickening of the skin and elephantiasis.
Physical examination of arms, legs and genital regions may reveal signs of skin thickening and inflammation.
Night blood culture, Lymph node aspirate may reveal microfilariae. Polymerase Chain Reactions (PCR) and antigenic assays are useful in diagnosing amicrofilaraemic cases.
The recommended treatment to terminate adult filarial worms is a broad spectrum anti-helmintic medication like albendazole along with a broad spectrum anti parasitic medication like ivermectin.
Another effective combination therapy is diethylcarbamazine (DEC) along with albendazole.
Mass distribution of medicines that kill the microfilaria and stopping transmission of the parasite by mosquitoes in endemic communities by implementing global eradication programs is the only way to eradicate the disease since no vaccines are available
