This is a tricky question about cholera.. please help me..?

Question:

In 1892, a critic of the germ theory of disease named Max von Pettenkoffer sought to discredit Robert Koch's work by drinking a culture of cholera bacilli diluted in water. Surprisingly, he only had a mild diarrhea! What factors may have contributed to the failure of the bacilli to cause cholera in his body?

Answers:
He may have cheated, he may have been naturally immune, he may not have taken it in sufficient concentration to cause him harm, Do we know if he ha a gigantic meal or a lot of alcohol before he drank the solution?

The bacilli were mostly dead, or they weren't cholera bacilli.

this IS tricky, it could be the circumstances that the bacteria was consumed...how diluted or weakened? and also on the drinker's immunity...

Perhaps he was not truthful about the severity of his illness.

Not everyone is equally susceptible to cholera. Genetics seem to play a role, and people with type A blood appear to be more resistant than type O. Healthy adults are more resistant than older individuals or children.

A normal healthy adult would need to ingest over 1,000,000 cholera bacilli to become infected. It's possible that Pettenkofer didn't consume enough of the sample, or that his immune system was simply strong enough to dispatch the infection with only minor symptoms. If, in fact, this ever happened at all.

This is a tricky question about cholera.. please help me..?

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