Surgical Care
Nodulectomy has been a traditional form of therapy in Mexico and Guatemala. Moving from village to village, healthcare workers remove nodules from patients, especially nodules in the head.
This surgical approach may reduce the number of microfilariae that enter the eye, but no strong evidence supports its effectiveness in preventing blindness. The removal of nodules may be a valuable adjunct in patients treated with ivermectin.
Prevention
Mass administration of ivermectin is the main strategy to achieve onchocerciasis elimination. [28] 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 future challenges. [28] 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.
Long-Term Monitoring
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.
-
Leopard-spot pattern of depigmentation on the shins. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Dermatitis associated with microfilaria. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Hanging groin sign. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Hanging groin sign. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Onchocercoma. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Onchocercoma. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Photomicrograph of a skin biopsy specimen from a patient with onchocerciasis. A worm is shown in cross-section. Courtesy of Brooke Army Medical Center teaching file. All images are in the public domain.
-
Photomicrograph from a gravid female worm (hematoxylin and eosin]). Courtesy of Brooke Army Medical Center. All images are in the public domain.
