Y’know... it’s not like we did NOT know this 100 years ago...
The title of this thread, as presented, is a little misleading.
River Blindness and Cholera are caused differently. Cholera is caused by a bacterium. Onchocerciasis (River blindness) is caused by a parasite, transmitted by a type of fly.
Ivermectin, among other efforts, has been used in programs to control Onchocerciasis; sanitation and vaccine have been used to combat cholera.