Prevention, control and elimination of onchocerciasis

Vector control

Vector control involves killing the larvae of the black fly vectors through the judicious use of environmentally safe insecticides.

In the 1970s, the Onchocerciasis Control Progamme in West Africa (OCP) achieved vector control by weekly aerial spraying of insecticides over fast-flowing rivers and streams. It took more than 14 years to break the life-cycle of the parasite through aerial spraying, combined from 1989 with treatment of eligible populations with ivermectin.

In four areas of Uganda, the United Republic of Tanzania, and Equatorial Guinea, African Programme for Onchocerciasis Control’s (APOC) strategy of community-directed treatment with ivermectin has been supplemented by activities to eliminate the black-fly vector. Vector control is not considered feasible or cost-effective in the remaining APOC countries.

Oral ivermectin at a dose of 300 µg/kg single dose repeated after 7 days proved effective for the treatment and prophylaxis of scabies in an infected institutional environment. Read more on scabies

WHO response

WHO is the executing agent of APOC.

The WHO Regional Office for Africa supervises APOC’s management in collaboration with the Committee of Sponsoring Agencies and WHO headquarters.

Through the Programa para la Eliminación de la Oncocercosis en las Américas (OEPA) partnership executed by the Carter Center, WHO collaborates with endemic countries and international partners.

WHO is currently facilitating the launch of an elimination programme in Yemen in collaboration with the Ministry of Public Health and Population, the World Bank in the Middle East and North Africa Region and other international partners.

Onchocerciasis Control Programme (OCP)

Between 1974 and 2002, onchocerciasis was brought under control in West Africa through the work of the Onchocerciasis Control Programme (OCP), using mainly the spray of insecticides against black-fly larvae (vector control) by helicopters and airplanes. This was supplemented by large-scale distribution of ivermectin since 1989.

The OCP relieved 40 million people from infection, prevented blindness in 600 000 people, and ensured that 18 million children were born free from the threat of the disease and blindness. In addition, 25 million hectares of abandoned arable land were reclaimed for settlement and agricultural production, capable of feeding 17 million people annually.

African Programme for Onchocerciasis Control (APOC)

In 1995, the African Programme for Onchocerciasis Control (APOC) was launched with the objective of controlling onchocerciasis in the remaining endemic countries in Africa. It is a global partnership which brings together endemic African countries, donors, Non-Governmental Development Organizations (NGDOs), the private sector and the affected communities.

In the rural sub-Saharan Africa where health systems are weak and under-resourced, APOC’s main strategy has been the establishment of self-sustaining community-directed treatment with ivermectin (CDTI), and, where appropriate, vector control with environmentally-safe methods.

Active community engagement and participation has successfully empowered communities to manage and supervise the distribution of the medicine, ivermectin to millions of people. The intervention is explained to the community through a process of sensitization and engagement following which the community decides on how, when, where and by whom the intervention will be implemented. The community itself has the responsibility for organizing and carrying out treatment of its members. CDTI strategy has become a vehicle for the delivery of appropriate health interventions to remote communities. By means of this strategy, the programme plans to achieve onchocerciasis elimination in most of the endemic countries by 2025.

More than 100 million people were treated in 2013 through community-directed treatment with ivermectin in 24 countries1. At least 25 million additional people need to be reached in the next few years as programme now shifts from control to elimination.

Onchocerciasis Elimination Programme for the Americas (OEPA)

OEPA is a regional partnership which was launched in 1992. Its goal (under the Pan American Health Organization [PAHO] Directing Council resolutions CD48.R12 and CD49.R19) is to interrupt onchocerciasis transmission in the Region of the Americas by 2015. Its strategy is the provision of mass drug administration (MDA) with ivermectin tablets at least twice a year to all communities in endemic areas, reaching at least 85% treatment coverage of eligible populations. The partnership includes the governments of endemic countries, the Carter Center (the executing agent), WHO/PAHO, the United States Agency for International Development (USAID), Lions Clubs International and local Lions Clubs, the United States Centers for Disease Control and Prevention (CDC), the Bill & Melinda Gates Foundation, several universities, institutes, and the Mectizan Donation Programme.

Following successful large-scale treatment of populations in affected areas in Latin America since 1992 with the support of international partners, Colombia and Ecuador were able to stop transmission of the disease in 2007 and 2009 respectively, leading to successful verification of onchocerciasis elimination by WHO in 2013 and 2014 respectively. Mexico and Guatemala were also able to stop transmission in 2011 and are currently completing and filing a formal request to WHO for similar exercise. So far, 11 out of 13 foci in the Americas have stopped MDA. The remaining two foci (one in Brazil and the other in Venezuela) are actually a single transmission zone shared by the two countries. These two foci stand as the last cross-border challenge to eliminate the disease among the Yanomami indigenous people within the region.

At the 66th session of the World Health Assembly (WHA66) in May 2014 in Geneva, Ministers of Health from Brazil and Venezuela signed a new bi-national agreement that specifically aims to heighten coordinated cross-border health interventions required to break transmission in the Yanomami Area as soon as possible. The agreement would allow to extend the mass drug administration (MDA) strategy, additional technical and administrative personnel, improved surveillance, and a binational technical multi-disciplinary team that engages the Yanomami people in the decision making process. Cross border operations to provide treatments and to find any as yet undiscovered communities along the border would be addressed by a technical committee to be constituted as part of the new agreement.

1Benin, Burkina Faso, Burundi, Cameroon, Chad, Congo, Côte d’Ivoire, Democratic Republic of Congo, Ethiopia, Equatorial Guinea, Ghana, Guinea, Guinea Bissau, Liberia, Malawi, Mali, Nigeria, Senegal, Sierra Leone, South Sudan, Sudan, Togo, Uganda and the United republic of Tanzania.