infectious diseases
Loiasis
Introduction
Loiasis is a filarial nematode infection withLoa loa. Symptoms include localized angioedema (Calabar swellings) in skin and subconjunctival migration of adult worms. Diagnosis is by detecting microfilariae in peripheral blood or seeing worms migrating across the eye. Treatment is with diethylcarbamazine. (See also Approach to Parasitic Infections and Loiasis is confined to the rain forest belt of western and central Africa. Humans are the only known natural reservoir for this parasite. Loa loamicrofilariae are transmitted by day-biting tabanid flies (Chrysops[deer fly or horse fly]). Microfilariae mature to adult worms in the subcutaneous tissues of the human host; females are 40 to 70 mm long, and males are 30 to 34 mm long. The adults produce microfilariae. Adults migrate in subcutaneous tissues and under the conjunctiva of the eye, and microfilariae circulate in blood. Flies become infected when they ingest blood from a human host during the day (when microfilaremia levels are the highest). Occasionally, infection causes cardiomyopathy, nephropathy, or encephalitis. Eosinophilia is common but nonspecific. 