Ask Lemmygrad

I know you didn't bring it up but the 90% thing is a myth. Rates were different for different outbreaks and many of the deaths chocked up to disease that contributed to the depopulation of Mesoamerica and the Gulf region (now US South) was due to mass slavery by the Spanish and Portuguese who were destroying villages and capturing slaves to work them to death mining silver and gold for a 7 year life expectancy in captivity.

Certainly some communities were hit extra hard by outbreaks, whole villages wiped out like the one the Mayflower colonists would inhabit with homes and food stores ready-made by the deceased.

However disease was consistently the largest killer during wars in the Colonial period. Outbreaks would kill half the population in the aftermath of wars throughout pre US and US history like that in the north east during the 1776 events and those in Oregon country right after Plateau wars in the 1850s and 60s.

Being displaced from sources of medicine, being displaced from clean water and food, losing elder knowledge keepers to the diseases, those elders were also more likely to be killed in a Conquistador's raid. There are many compounding reasons why disease was so rampant and deaths due to war usually came in the form of disease, for instance, some estimates put half the deaths in WW2 to disease and famine.