Yes, I agree but probably not so unusual in New York back in those days. Malaria, too, was common. The sad thing is that, as you say, Angus was so far from home. It's a pity New York state didn't have death certs showing who the informant was. Perhaps it was a family member, or perhaps a local contact.
I'm sending my account of what is known so far about Angus to your home email address.