Horse manure. The Japanese man who first discovered these compounds first used it on nematodes of mice.The drug has been shown to have no effect on the symptoms of or treating the virus. Period. I'm gonna go out on a pretty thick limb and say your friends would have been just fine without taking the horse paste.
Ivermectin has been used for decades to treat parasitic infections in humans. When the savior first starting hawking it as miracle cure, a lot of people went out and bought the horse paste. Hence the constant running joke about de-worming. It's a way of making fun of people who believe any conspiracy theory uttered by their media masters.