[Burkeman1]

Some recent scholarship on the Great Plaugue posits that it was actually two plagues aperating simultaneously. One was the traditonal bubonic plauge spread by flea bites or another infected person. The other is as yet unknown but some suspect a deadly flu virus. Two types of symptons have repeatedly been talked mentioned by primary sources- one is the bubous swelling, black oozing pus symptons and the other is a bubous free fierce fever that dehydrated the body and could kill in as little as 24 hours.

[SoCal Pubbie]

I read a bit about these new theories. Another possible explanation is anthrax. Indeed tests done on areas where black death victims were buried in mass graves in England produced anthrax spores. Some still living, I think!