Why does papaya and papaya nectar cure a stomach virus?

My answer is purely conjecture, because I've never heard that papaya will "cure" a stomach virus. But there are certain characteristics of papayas that could be used to explain such if true. Papaya fruits have strong concentrations of enzymes that could potentially break down the protein coatings around the viruses. Back in the days when I wore hard contacts, I used tablets containing papain, a derivative of papaya, to remove the protein deposits on my lenses after long periods of wear.