And now we've arrived at the debate behind the Third Edition of Webster's Dictionary. Are dictionaries to be a record of historic usage, or current usage? The Third Edition leaned completely in the direction of the the latter, and caused a lot of controversy in the dictionary world. I tend to lean towards the former view on how dictionaries should function, or else we'll lose all ability to understand historic texts as definitions drift over time.

The poignant example being "acquire", which historically implied "getting by one's own efforts" but has drifted to be used more passively now.

"Acquiring" usually implies "by one's own efforts" rather than being infected with a disease.

Yes. The word "contract" would be ambiguous between the people being infected with malaria in the US or them developing symptoms in the US after having been first infected while abroad. Using "acquire" doesn't present that ambiguity.

When a company contracts another company, the latter will eventually go away after it's dealt with, but when a company is acquired, it will stay forever.

So I guess diseases are similar? :-)