Mass drug administration campaigns of the drug ivermectin kill the parasite's larvae in the human body and slow down transmission to others. However, ivermectin does not kill the adult worms that can continue to produce larvae until they die naturally. For this reason, ivermectin has to be taken once a year for 16–18 years to break transmission.

The lingering presence of adult worms in humans means there is a risk that the disease will re-emerge. According to the Carter Center, the Mesoamerican populations at the highest risk for a re-emergence of onchocerciasis are mestizo and indigenous communities who live on coffee plantations. To accelerate and secure the elimination effort in the region, a macrofilaricide drug that kills the adult worms is needed.