Dermatologic Manifestations of Onchocerciasis (River Blindness) Follow-up
- Author: Jason F Okulicz, MD, FACP, FIDSA; Chief Editor: William D James, MD more...
Further Outpatient Care
Considerable debate exists regarding the proper dosing frequency of ivermectin in endemic areas. The drug is given from every 3 months to every year, depending on the degree of symptoms, cost constraints, and patient compliance.
In nonendemic areas, a reasonable approach is the administration of a single dose of ivermectin. Depending on the patient's skin symptoms, the dose can be repeated every 3-6 months as needed. Strict follow-up care to determine the need for therapy is important after several doses are administered. The continuation of treatment throughout the entire 12- to 15-year life cycle of the worm has not been proven effective.
Nodulectomy remains an important adjunctive treatment.
The Onchocerciasis Control Programme (OCP) began in 7 West African countries in 1974. The major strategy for interrupting transmission of onchocerciasis was vector control. Hand spraying of black fly breeding sites along rivers, combined with the aerial distribution of larvicide, has been successful in this region. To prevent reinvasion by black flies, parts of 4 other countries were also included in 1986. This program closed in 2002, with all subsequent control efforts transferred to the participating countries.
The introduction of ivermectin in 1987 allowed assistance to be extended to other areas. Merck & Co decided to provide the drug, at no cost, in whatever quantities were needed, for as long as it was needed. Community-based distribution programs were established in endemic areas to administer the drug 1-2 times per year, even to remote villages.
Encouraged by successes with the OCP and ivermectin, the World Bank launched the African Programme for Onchocerciasis (APOC) in the remaining areas of Africa in 1995. The goal of the program is to eliminate the disease as a public health issue in these areas by 2007. Unlike the OCP, the APOC uses the community-based distribution of ivermectin as its primary control strategy. The Onchocerciasis Elimination Program for the Americas (OEPA), a similar program, also aims to eliminate onchocerciasis by 2007 in the Americas.
These programs face many challenges in the future. Whether or not successful control of the disease can be accomplished without the use of vector control has yet to be determined. The organization and effectiveness of community control programs, as well as their funding, may need to be addressed.
The prognosis for onchocerciasis is good in patients who receive proper therapy before irreversible eye lesions develop. Ivermectin is effective in reducing the skin manifestations of the disease; it thereby reduces morbidity and improves the patient's quality of life.
In 1995, an estimated 270,000 people were blinded and another 500,000 had severe visual impairment as a result of the disease. A multicountry study showed that more than 30% of the population in endemic areas have onchocercal dermatitis. In a survey of skin disease in 7 endemic sites in 5 African countries, 40-50% of adults reported troublesome itching. Blindness is not associated with excess mortality. However, increasing microfilarial load is associated with mortality in both males and females.
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