in the Southern Chiapas Focus, México

The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission. (0.05%; one sided 95% confidence interval = 0.08%).The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community