New Theory on Conquistador Plague on Shaky Ground

It is pretty much historical dogma that part of what made the Old World so easily conquer the New World, and its inhabitants, was the role of Old World diseases decimating native populations even before explorers reached their villages. Even the title of Jared Diamond's book acknowledges the prominence of disease in Guns, Germs, and Steel: The Fates of Human Societies. Now, a microbiologist, reading a translation of a doctor's eyewitness account of the third wave of plagues in Mexico, posits that this third wave, the most devastating according to Mexican historians, came from native hemmhoragic fever instead of transplanted bubonic plaque, typhoid fever, or measles. The new theory is based solely on the latin writings of the Spanish doctor, explaining that "[b]lood flowed from the ears and in many cases blood truly gushed from the nose." The vector for the hemmhoragic fever theory is rodents, which the researchers claim would not have been in contact with the Spaniards in the outlying villages, where they claim the epidemic got its start. But if this was hemmhoragic fever, that eventually got to the larger settlements, where the conquistadors were, how did the spaniards escape the ebola-like virus? The rodents may be responsible for the bringing the disease across great distances, but once it's in a major population center, the infectiousness of the virus, whether that's fluid, aerosol, or contact, takes over. And it would have to be very infectious to take out the estimated millions in the 1576 outbreak. Where were the spaniards bleeding from their ears and noses? One written account may add some confusion to the overall picture, but because one account's pathology does not match the epidimiology is not enough to revise history in this matter.