Welcome, betterdaze- glad to see you here. I have never read any article in WT publications about mass extinction events past or future occurances.
Meteor/comet impact, mega volcano, magnetic pole reversal, gamma ray burst from a nearby star imploding ( thought to have happened in N-America within the last 20,000 years), massive solar flare, runaway mutant virus, ice age, global nuclear war- well that's 8 - the virus wouldn't harm Earth just humans.