I’ve been reading a bit on Norse colonization during the period of Viking expansion, and read a bit about how they actually had some contact, albeit limited, with native North Americans in Greenland and the fringes of what’s now Canada. This got me thinking- did the norsemen spread the diseases that would eventually devastate the Americas following Columbus’s voyages to these tribes? And if so, why didn’t they sweep down into the rest of North America 500 years early? Were the tribes likely too isolated? Or if the norsemen didn’t spread their European diseases, how were they able to avoid doing so? Was smallpox just not common among the Viking settlers?
Duo to the lack of written sources about Viking colonies in North America, this is a hard question to answer.
Firstly, is important to note that the populations of both natives (Inuit) and Vikings in these areas was not very big and because of the region's size isolated from each other. We also have reasons to believe (mostly duo to their interactions with the English, French and Dutch centuries later) that the natives in the area were reluctant to trade and interact with outsiders. These are key points because a desease such as smallpox require a minimal population density in order to sustain itself. Furthermore, Viking settlers depended much more on farming than on livestock and didn't bring with them as many animals as the later explorer and colonizers did. This is particularly important because the lack of hygiene and proximity to animals is among the main reasons desease spread in Europe. All of this made it very hard for most deseases to spread among the people, survive and even harder for it to spread to the mainland.
I've read somewhere before that a epidemic could've killed the population almost entirely and they recovered afterwards but as far as I know there isn't any archeological evidence for that.
SOURCES:
Davis, Graeme. Vikings in America. Birlinn, 2011.
Gear, W. Michael, and Kathleen O'Neal Gear. Vikings in North America. Capstone Press, 2008.