A microfilaria observed in a skin nodule from a patient in Central America is most likely which organism?

A microfilaria observed in a skin nodule from a patient in Central America is most likely which organism?

• A. Onchocerca volvulus
• B. Wuchereria bancrofti
• C. Brugia malayi
• D. Loa loa

Answer: (A)

Microfilariae in skin nodules point to Onchocerca volvulus infection, because adult worms form subcutaneous nodules and release microfilariae that migrate through the skin, causing dermatitis and pruritus. In Central America, this species is a classic cause of skin-dwelling microfilariae. Other filariae have different habitats: Wuchereria bancrofti and Brugia malayi live in lymphatics with microfilariae circulating in blood, not in skin nodules; Loa loa migrates in subcutaneous tissue and is more typically associated with Africa and ocular migration. So, the finding fits best with Onchocerca volvulus.

Microfilariae in skin nodules point to Onchocerca volvulus infection, because adult worms form subcutaneous nodules and release microfilariae that migrate through the skin, causing dermatitis and pruritus. In Central America, this species is a classic cause of skin-dwelling microfilariae. Other filariae have different habitats: Wuchereria bancrofti and Brugia malayi live in lymphatics with microfilariae circulating in blood, not in skin nodules; Loa loa migrates in subcutaneous tissue and is more typically associated with Africa and ocular migration. So, the finding fits best with Onchocerca volvulus.