Progress in eliminating onchocerciasis in the WHO Region of the Americas: report from the XXXV Inter-American Conference on Onchocerciasis (IACO) 2025

Overview

Onchocerciasis is a parasitic disease caused by Onchocerca volvulus and transmitted by Simulium blackflies. Following WHO recommendations, the OEPA strategy, based on repeated and sustained ivermectin mass drug administration (MDA) achieving at least 85% coverage of eligible populations, has resulted in the elimination of transmission in 11 out of thirteen endemic foci in the region.

By 2025, transmission remains only in the YFA, affecting an estimated 39 701 individuals in 715 communities distributed across a remote and highly dispersed cross-border region between Brazil and the Bolivarian Republic of Venezuela. The YFA accounts for approximately 7% of the regional population originally requiring preventive chemotherapy for onchocerciasis, reflecting the remarkable progress achieved in the Americas.

The WHO Neglected Tropical Diseases (NTD) road map (2021–2030) emphasizes sustaining high ivermectin treatment cov erage, strengthening country ownership and integrating programmes into health systems, particularly at the midterm review point in 2025.