Research article

Impact of long-term treatment of onchocerciasis with ivermectin in Ecuador: potential for elimination of infection

Juan Carlos Vieira^1,2 , Philip J Cooper² , Raquel Lovato^1,2 , Tamara Mancero³ , Jorge Rivera^1,2 , Roberto Proaño^1,2 , Andrea A López² , Ronald H Guderian² and José Rumbea Guzmán¹

¹Programa Nacional de Eliminación de la Oncocercosis en el Ecuador, Servicio Nacional de Control de Enfermedades Transmitidas por Vectores Artrópodos, Ministry of Public Health, Guayaquil, Ecuador

²Desarrollo Comunitario Vozandes HCJB, Casilla 17-17-691, Quito, Ecuador

³Pan American Health Organization, Georgetown, Guyana

author email corresponding author email

BMC Medicine 2007, 5:9doi:10.1186/1741-7015-5-9

Published:	23 May 2007

Abstract

Background

Onchocerciasis is a leading cause of blindness worldwide, hence elimination of the infection is an important health priority. Community-based treatment programs with ivermectin form the basis of control programs for the disease in Latin America. The long-term administration of ivermectin could eliminate Onchocerca volvulus infection from endemic areas in Latin America.

Methods

A strategy of annual to twice-annual treatments with ivermectin has been used for onchocerciasis in endemic communities in Ecuador for up to 14 years. The impact of ivermectin treatment on ocular morbidity, and O. volvulus infection and transmission was monitored in seven sentinel communities.

Results

Over the period 1990–2003, high rates of treatment coverage of the eligible population were maintained in endemic communities (mean 85.2% per treatment round). Ivermectin reduced the prevalence of anterior segment disease of the eye to 0% in sentinel communities and had a major impact on the prevalence and transmission of infection, with possible elimination of infection in some foci.

Conclusion

The distribution of ivermectin in endemic communities in Ecuador might have eliminated ocular morbidity and significant progress has been made towards elimination of the infection. A strategy of more frequent treatments with ivermectin may be required in communities where the infection persists to achieve the objective of elimination of the infection from Ecuador. The elimination of the infection from an endemic country in Latin America would be a major public health achievement and could stimulate the implementation of elimination strategies in other endemic countries.