The 35-year-old volunteered as a ‘fly catcher’ on the Aruu river in northern Uganda, near his village of Lapaya, which is a breeding ground for the tiny black flies that spread the disease.
Fly catchers are the frontline heroes in the global fight to eliminate river blindness, an infectious disease that can eventually lead to irreversible sight loss.
In this area of Uganda, the fly catchers spend 12 hours once a week sitting on rocks close to the river. They wait for the flies to land on them: when they spot one, they catch it in a test tube before it has a chance to bite them.
The volunteers record how many flies they catch each hour and each day, to monitor how many there are in the area. The flies themselves are then preserved in liquid and sent to a lab for testing. This is vital in the fight to control the disease: it is important to know both how many flies there are and to what extent they are carrying the parasite that causes river blindness.
The team also doses the river with chemicals to prevent the flies from breeding, a process known as vector control.
Okello now works as a local volunteer, distributing the antibiotic Mectizan® to treat the disease. Despite this, he didn’t originally take it himself, so eventually he became infected and began losing his sight.
He has since started taking the medication and it has made a huge difference: his sight is now returning, and he uses himself as an example when people are reluctant to take the drug.
“I always educate that person who is hesitant to take the treatment,” he explains. “I give the example of myself – I tell the disadvantages I had before taking the treatment. Right now, where I distribute drugs, nobody is resisting.”
His work is part of the UK aid-funded programme to eliminate river blindness and lymphatic filariasis.