A look at four "zombie" viruses from ancient times set to come out of the permafrost, and one other hidden disease proven to be deadly for humans.
Researchers were able to demonstrate that the plague was present in England well before the widely-known Black Plague outbreak of the Middle Ages.
While the viruses' risk to humans remains low, the researchers noted only a few amino acid changes are needed for that to change.
Climate change is likely the culprit for mosquitoes arriving earlier, as warming temperatures were seen to impact diseases transmitted by mosquitoes in other places.
Black irises could be used as a likely indicator of prior infection with avian influenza.
The new study, which has not yet been peer-reviewed, studied virus samples taken from infected birds and mammals.
Using stem cells from umbilical cord blood instead of from donors increases the potential to cure the disease through stem cell transplants in people of all racial backgrounds.