Kallu, a 30 years old man, presented with subcutaneous itchy nodules over the left iliac crest. On examination they are firm, non-tender and mobile. Skin scrapping contains microfilaria and adult worms of:

Ans. (b)O. volvulus-causes onchocerciasis in man. The worms develop in the subcutaneous tissue often encapsulated in dense fibrous nodules. The nodules occur over anatomic sites where the bone is superficial such as knees, hips, iliac crests, elbow, ribs, scalp etc. The nodules are movable. The microfilariae live in the superficial layers of the skin causing itching and in heavy chronic infections, gross thickening of the skin.Loa loa--causes loiasis. The adult worms live in subcutaneous connective tissues and wander round the body causing, usually painless, oedematous swellings known as fugitive or calabar swellings.B. malayi causes lymphangitis and elephantiasis. It is characterized by absence of chyluria and rarity of scrotal swelling.Mansonella persfans-live adults appear to produce little or no host reaction, however, eosinophilia is common. Pruritis, abdominal pain, urticaria and calabar like swellings occur.