GWEN IFILL: Next, the second of Ray Suarez's global health reports from the East African nation of Tanzania. Tonight, Ray looks at efforts to combat river blindness.
RAY SUAREZ: The town of Tangeni in Tanzania's southern highlands is like other villages in Tanzania's agricultural heartland. Everything revolves around the river: washing, bathing, farming.
The climate is tropical. The people are subsistence farmers. The village itself snakes for miles through the mountains along the water's edge.
But the same water that is Tangeni's lifeline also brings danger. The river is home to terrible tropical diseases that wreak havoc on Tangeni's population, diseases like river blindness, which can cause severe skin aliments and loss of eyesight.
Dr. Grace Saguti is an ophthalmologist.
DR. GRACE SAGUTI, ophthalmologist: Someone will scratch her or himself the whole day, 24 hours. This person in this community has to go to the farm, has to cultivate in order to get food. So scratching themselves for the whole day, they cannot produce, they cannot take care of their family, they cannot progress economically. Health-wise, they will be also affected, because you cannot even have good food in order to be healthy. So it's all psychological, social and economical effect.
RAY SUAREZ: Worldwide, 37 million people are infected with onchocerciasis, more commonly known as river blindness. Most live in poor rural Africa.
The fly that brings river blindness prefers to breed in fast-running water, so the mountainous areas of this country are more prone to the disease, and it's not just one bite that infects a person. It's being bitten repeatedly so that the worm that causes the terrible disease gets to breed inside the human body.
DR. GRACE SAGUTI: When the fly breeds, it needs the human blood in order to -- for the eggs to mature. It also goes in a cycle. It grows to become a big worm. And the female and the male worm, when they mate, they produce, so it takes years.
RAY SUAREZ: To break the life cycle of the worm, villagers in Tangeni gather once a year at the local health dispensary to collect lifesaving drugs for their neighbors.
The volunteer program, called Onchocerciasis Control, or APOC, uses local villagers across Africa to distribute ivermectin, a drug donated by Merck, that must be taken every year for 15 years.
Community drug distributors go house to house using a measuring stick to determine the proper dosage for each resident. Each visit is carefully recorded. The team will be back in a year with the next pills.
Dr. Uche Amazigo oversees the drug distribution program.
UCHE AMAZIGO, World Health Organization: They have come together to establish a huge network in all of these communities, in more than 120,000 communities in sub-Saharan Africa. And each distributor of ivermectin treats at least 50 to 100 people in a year, distributes drugs. Some of them distribute them to 500 people in a year.
RAY SUAREZ: The World Health Organization announced drug distribution results in July: a dramatic drop in cases of river blindness. The program's so effective that new drugs are being given to distributors to prevent other diseases, ones often referred to as "neglected tropical diseases." Over 1 billion people suffer from one or more of the neglected diseases.
UCHE AMAZIGO: We coined the word "neglected," because it was absolutely important to draw the attention of the leaders, politicians, and the big agencies to the fact that, whilst we talk about the big three -- malaria, T.B., HIV -- it is equally important to talk about those diseases of the poorest that have no voice. If you pool all of them together, the burden of these diseases outweigh that of malaria or HIV-AIDS.
RAY SUAREZ: In addition to taking drugs for river blindness, everyone in Tangeni also takes drugs for lymphatic filariasis, commonly called elephantiasis.
DOCTOR: You can see this is their skin, a typical, and they are -- he is already affected with this lymphatic filariasis.
RAY SUAREZ: This elderly couple has both diseases.
DOCTOR: This sign is spotty, this is his skin.
RAY SUAREZ: He has elephantiasis; she went blind from river blindness.
DOCTOR: She was using a knife to scratch.
RAY SUAREZ: But it's better now?
DOCTOR: Ah, it's better. You can see it, the spots.
RAY SUAREZ: If you pick up the newspapers or the magazines in the United States, what will you see? You'll see malaria, AIDS, tuberculosis. Is that a problem? Is the world making a mistake paying so much attention to those other maladies?
DR. GRACE SAGUTI: I think it's a human instinct to fear diseases which cause mortality faster. If death comes because you have a malaria for one week, people will be afraid. Then having onchocerciasis, which will maybe manifest after years and it cause morbidity slowly, disability slowly, so people are focusing on diseases which kills very fast and forget that there are diseases which kill slowly.
RAY SUAREZ: With so much money flowing into care for HIV-AIDS, malaria, and T.B., some say community drug distributors could do even more, like give out anti-malaria beds nets, for example.
UCHE AMAZIGO: Give him malaria treated nets. He will at the same time distribute because the community has selected him to be their distributor. The community has empowered him to come to their house, go house to house, and distribute drugs to them. So at the same time, it's cost effective, if he could get all that health commodities with him.
RAY SUAREZ: Distributors are not paid, but the work brings status. The village holds a big celebration to honor them.
UCHE AMAZIGO: We don't pay our distributors. The community people take care of them. Other programs do, they pay huge sums, and these are not sustainable. They're not sustainable. The dollars will fizzle out someday. They will dry out. But the people will remain. So you need to empower the people to realize that this is their problem.
RAY SUAREZ: On this day, villagers who have distributed drugs for five years were given new bicycles.
MEDICINE DISTRIBUTOR (through translator): I enjoy volunteering and helping my village improve their health.
RAY SUAREZ: The bicycles and celebrations are just a small piece of the community pride now shared in this African village.
GWEN IFILL: Tomorrow, Ray's last report will examine the campaign to rid Tanzania of malaria. On our Web site, newshour.pbs.org, find out more about river blindness and view a slide show from Ray's reporting trip.