People in villages often live on the land that belonged to their families several generations back, and do not move away in adulthood. This means that cousins live near each other, too, and will help with care for family members who are absent when health workers visit.

It is easier and more efficient to distribute medications when tapping into these large family structures, Katabarwa said. Through this approach, many more women have joined the effort to distribute the medicines because they are comfortable working among their family members.

Toward elimination

Elimination in 2020 is the goal for Uganda, but river blindness is harder to control in some parts of the country because of environmental and political factors, Unnasch said.

There are places where insecticide resistance is a problem with a particular species of black fly that also moves around a lot, he said, especially on the border with South Sudan and the Democratic Republic of the Congo.

Doing any kind of river blindness control in Democratic Republic of the Congo is problematic because of safety issues, he said. A lack of government structure also makes it hard for health workers to coordinate efforts. But the flies don't respect the border between DRC and Uganda, and people belonging to the same tribe in both countries migrate across, too.

"If you're controlling it on the Ugandan side, and doing nothing on the DRC side," Unnasch said, "you're never going to really eliminate it until you deal with these cross-border issues, and get an effective program going."

Unnasch commended the work that the Carter Center has been doing. He and Katabarwa travel together to Uganda every year. They are both part of an expert committee on river blindness through the country's Ministry of Health.

"When summertime rolls around, and the rains start to come and the flies go out, that's when we need to be there," Unnasch said.