ONCHOCERCIASIS
IN AFRICA
HEALTH INTERVENTIONS
MECTIZAN (IVERMECTIN) DONATION PROGRAM
The Mectizan Donation Program (MDP) developed by Merck has been providing free treatments to any organization that demonstrates need and the ability to distribute the drugs efficiently since 1985 (USAID’s, 2014). Mectizan (ivermectin) is a versatile drug that was first developed as a veterinary treatment for various roundworm parasites, but has since proven effective at treating Onchocerca volvulus and the parasite responsible for elephantiasis (Silver, 2016).
Mectizan is currently the only treatment for onchocerciasis. All other methods of killing the parasite are toxic to humans (USAID’s, 2014). It prevents the transmission of O. volvulus by killing the microfilariae (larval stage) of the parasite that are circulating in the body and still in the adult female. This reduces the abundance of microfilariae forming nodules in the skin and the production of new ones (USAID’s, 2014). A single dose of 150-200 mg/kg 1 time a year can reduce microfilarial density to near zero after one month, and maintain this low level for 12 months (Mectizan, 2016).This treatment is required for 10-15 years to ensure all adults and microfilariae are dead (USAID’s, 2014).
Initially treatment with Mectizan was not accepted by the communities in sub-Saharan Africa due to its adverse reactions including intensified itching (Silver, 2016). The increased itching is caused by the microfilariae dying and releasing toxins in the sub-cutaneous nodules they inhabit. Other documented reactions to mectizan include fever, rash, joint/muscle pain, rapid heartbeat, and painful tender glands. The reactions usually subside 2-3 after the treatment (Landau, 2013). After the positive effects of the treatment became known in the African villages, infected individuals were willing to take mectizan (Silver, 2016).
WHO PROGRAMS
The World Health Organization (WHO) has developed numerous organizations dedicated to the elimination of onchocerciasis throughout the world (USAID’s, 2014). The African Programme for Onchocerciasis Control (APOC) is the only one currently acting in sub-Saharan Africa. This program was launched in 1995 with the goal of controlling onchocerciasis in the endemic areas of Africa. The main strategy for this control was to establish self-sustaining community directed mectizan treatments (WHO, 2016b). In 2009, this goal switched from control to elimination of onchocerciasis with mectizan treatments and environmentally safe vector control methods. By 2014, more than 112 million people throughout 22 African countries were treated with mectizan (WHO, 2016b). The WHO hopes to have onchocerciasis under control in all treated areas by 2020 (The End Fund, 2016).
OTHER ORGANIZATIONS
Helen Keller International is an organization working with MDP and African governments to distribute mectizan across Africa. This organization also helps train community health workers in affected areas. The goal of this education program is to increase risk awareness, as well as, increase knowledge of the effectiveness of treatment programs available to citizens (Helen, 2014).
The Carter Center works with national ministries of health in both Latin American and Africa to help eliminate onchocerciasis through distribution of mectizan (Carter, 2016). By donating more than 200 million treatments, the center has helped achieve official elimination status of onchocerciasis is Colombia, Ecuador, and Mexico, and has stopped transmission in 15/17 original foci in Uganda, as well as other areas of sub-Saharan Africa. The center also is working to provide health education in conjunction with mectizan treatments to eliminate onchocerciasis in Africa (Carter, 2016).
INSECTICIDE TREATMENTS
Onchocerciasis was controlled using insecticides distributed by airplanes and helicopters from 1974-2002. Since 1989, mectizan treatments were used to supplement this vector control method (WHO, 2016b). However, these insecticides were not environmentally friendly. Currently, biodegradable insecticide treatments are being implemented in areas of Uganda that have shown a positive effect. This biodegradable insecticide, called Abate, is applied directly to the fast flowing rivers to prevent the development of black fly larvae in order to reduce the vector population. However, insecticide treatments are not effective by themselves. Simulium species of black flies from untreated areas will fly to treated areas and infect humans with O. volvulus (Landau, 2013).
For more information, please read the article below on Treating Neglicted Tropical Diseases provided by the US National Library of Medicine National Institues of Health.