Imagine having thousands of tiny worms swimming through your eyes for years, eventually blinding you. African river blindness (onchocerciasis) is a disease that plagues 37 million people worldwide, and is the second leading infectious cause of blindness. Onchocerca volvulus, the parasitic worm that causes the disease, is transmitted by the bite of a blackfly and deposited under human skin where it grows in a protective nodule to lengths of 50 centimeters (19 in.). Adult worms can live up to 20 years in a human host, releasing millions of tiny worms (microfilariae) each year. These microfilariae wreak havoc on the body, causing skin lesions, seizures, and the crippling blindness for which the disease is best known. River blindness is most dramatically a problem in 27 countries on the African continent, where over 90 million people are at risk of infection. Incredibly, this disease is both preventable and treatable by either (1) controlling the blackfly population with pesticides or by managing their breeding sites in running water, or (2) by administering the drug Ivermectin which kills the immature worms that constitute the clinical disease. Nodules harboring the parasite can be removed surgically in some cases, but this procedure comes with significant risk and is not a feasible method of mass treatment.
In 1987, pharmaceutical giant Merck & Co., Inc. made the unprecedented announcement that it would donate Mectizan® (Ivermectin) to “all who needed it for as long as needed”. So far Merck has spent $396 million to reach 60 million people in Africa, Latin America, and the Middle East each year, and has partnered up with the delivery company DHL to help get Mectizan to the patients who need it" Mectizan is a safe but insufficiently effective pharmaceutical used to treat river blindness once a person has been infected by the parasite. It works by killing the tiny immature worms called “microfilariae” that invade the body, thereby eliminating most clinical symptoms of the disease. Mectizan does not kill the adult worms, however, which remain in the body producing millions of microfilariae each year. Because the adult worms are spared, patients must remain on treatment for as long as it takes the adult worms to die, or for as long as disease transmission occurs; a period that now runs between 20 to 25 years.
Sustainability is a major obstacle to this method of treatment. In addition to the long treatment regimen, the African Programme for Onchocerciasis Control (APOC), the main organization overseeing Mectizan treatment programs, will dissolve when its funding is terminated in 2015, forcing Merck to seek out other methods of distribution. It is hoped that community directed programs, which have shown promise on the small-scale, will continue to control river blindness beyond 2015. If the intensity of river blindness control wanes during this period, or if new drugs that kill adult worms as well as microfilariae are not developed, experts warn that river blindness could return full-scale.
River blindness is still an important public health problem and a significant threat to people living in areas where transmission occurs. Does Mectizan reach the people it is intended to reach? Do all of the 37 million currently infected with the parasite have access to Ivermectin? What will happen when the main organizing body that distributes Ivermectin, the African Programme for River blindness Control, dissolves in 2015? What must be done to prevent a significant recurrence of this disease?
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