Their bodies were the battleground for parasites. Microfilaria were coursing through these people, the result of a female black fly sucking blood while depositing tiny larval forms of microfilaria that would mature as adult Onchocerca worms. As the microfilaria died, proteins released from a parasite they carried, Wolbachia, caused itching and inflammation that led to various ailments, blindness being the worst.
But help was on the way. It would not reverse the early eye symptoms, but it would stop the process and the itching. The help was the positive side of globalization, when the benefits of science and transportation came to their village.
Help started as a soil sample from a golf course in Japan. It yielded an anti-parasitic compound produced in soil by bacteria. Merck initially developed the substance to protect dogs against heartworms. But the company did not stop there. It developed and tested a human version of the drug. Then it faced a dilemma. Merck had a drug so good it could inhibit the microfilaria of onchocerciasisfor a year with a single dose. But the target population included some of the poorest people in the world. This was not a promising commercial endeavor.
In October 1987, Roy Vagelos, then the chief executive of Merck, launched the largest pharmaco-philanthropic venture ever. He approached me, as the head of the Task Force for Child Survival in Atlanta, and offered the drug — now copyrighted as Mectizan — for free if the task force could devise a distribution system. All requests had to be approved by a destination country’s ministry of health so that consistency with national priorities was assured.
There were concerns. How long would Merck give the drug for free? What if side effects were not noticed until millions had been treated? How could people be motivated to take the drug if freedom from blindness would not be realized for decades?
There was good news in the answers: Merck said that it would supply the drug as long as it was needed. Extended surveillance has shown this to be one of the safest drugs ever developed. And because the drug ended the itching suffered by so many, it was accepted much more easily than had been anticipated.
The original target of treating 6 million people in six years was achieved in four years. Only 15 years after the program started, 250 million treatments had been given. Last year, the Mectizan Donation Programprovided 140 million treatments for onchocerciasis in Africa, Latin America and Yemen. A quarter-century after the program began, 1 billion treatments have been provided free by Merck.