One of the young doctors asked for my opinion about a lesion on an old woman’s finger. It had been present for quite some time, but was giving the woman discomfort.
When I took a look at the finger, I had 2 questions for the woman: where did she live and has she suffered any visual changes. The answers to both confirmed my diagnosis of Onchocerciasis with an onconodule of her finger.
She was from the town on Nakpanduri which in the past was a hotspot for the blackfly (which is the vector for the parasite Onchocerca Volvulus that causes “river blindness” or onchocerciasis.)
As for the answer to the second question, I only had to look at her shriveled right eye as a sequela of the infection in her eye many years prior.
A bite from an infected blackfly will introduce the parasite into the human body. Once inside, the parasite creates nodules in the tissue under the skin, usually near bony joints. Inside the nodule, the adult worms can produce larvae which then infect the skin or eyes. In fact, the adult worms can live up to 15 years in these nodules. Once the worms die, they become calcified and hard. Characteristic findings can be seen on x-ray. This is why I was able to diagnose the problem based on the nodule and x-ray findings alone.
The nodule on her finger had completely engulfed her tendons, blood vessels and nerves to that finger. The only way to get rid of the nodule would be to amputate the finger. The woman agreed. We amputated the finger and she healed well. In the beginning stages of infection, treatment includes ivermectin +/- doxycycline to prevent long term complications. This woman presented only with long-term sequelae, and therefore long-term medicines were not needed.
For more information, visit the CDC’s page on onchocerciasis.