I’m no expert in this, but I learned a little about this in a psychology class I took:
Some psychologists believe that disgust is intimately tied into morality and ethics, and that disgust might even be the precursor to morality. Thus, disgust would be presumably a uniquely human quality. This has been studied in young children, where moral judgments regarding disgust emerge earlier that moral judgments regarding other things, such as danger.
For example: toddlers (~3 years old) will regard a lie as more “naughty” if it is a lie that causes someone to do something gross, like eating moldy bread, as opposed to causing someone to do something dangerous, like enter a house where a dangerous snake is. A review of this study can be found starting on page 13 of this pdf document.
Here’s one other article that discusses what I’m talking about. I can’t vouch for it, as I don’t have time to read the whole thing right now.