lonchocercose

Lonchocercose is a parasitic disease caused by the filarial nematode Onchocerca volvulus, more commonly known as onchocerciasis or river blindness. It is transmitted to humans through repeated bites of infected Simulium blackflies that breed in fast-flowing rivers and streams. The parasite’s microfilariae migrate through skin and ocular tissues, producing characteristic dermatological and ocular manifestations.

Clinical features include intense pruritus, chronic dermatitis with hyper- or depigmentation and skin thinning, subcutaneous nodules containing adult worms, and progressive ocular disease that can culminate in visual impairment or irreversible blindness. Symptoms often develop years after initial infection and may cause substantial disability and social stigma.

Diagnosis is typically made by demonstrating microfilariae in skin snips, slit-lamp examination of the eye, or by molecular and serological tests in epidemiological settings. Imaging and clinical evaluation assess the extent of ocular and cutaneous involvement.

Treatment centers on mass administration of ivermectin, a microfilaricidal drug that reduces skin and eye microfilariae and lowers transmission when given periodically. Doxycycline targets Wolbachia bacterial endosymbionts of the worm and can reduce adult worm viability and fertility, but requires prolonged courses. Surgical removal of palpable nodules may be used in some cases. Vector control and community-wide treatment campaigns are key public health strategies for control and elimination.

Lonchocercose is endemic mainly in parts of sub-Saharan Africa, with focal transmission in Latin America and Yemen. Effective programs combining drug distribution, vector control, and surveillance have substantially reduced disease burden in many areas.