Ivermectin is an anti-parasitic drug developed during the 1970s as a partnership between the kitasato institute in japan and merck & co. the project was led by satoshi omura and william campbell on each side respectively. given its broad spectrum against internal and external parasites that improved animal health and boosted productivity, ivermectin quickly became a blockbuster drug in the veterinary field.
during the 1970s, the world was waging a war against river blindness, also known as onchocerciasis, a disease caused by the onchocerca volvulus parasite in rural areas that crippled whole communities. some success had already been achieved thanks to the involvement of the world bank. but once ivermectin was commercialized, it was noticed that onchocerca cervicalis, the agent of onchocerciasis in horses, practically disappeared in areas where the new drug was used