Diseases, whether native or exotic, irrupt in populations that are nutritionally stressed. Chlamydiosis irrupted in koalas in the 1900s as declining eucalypts succumbed to the Federation Drought. Same again in the Millennium drought. Tas Devils disease irrupted as their prey declined when scrub engulfed naturally grassy forests and woodlands after greens stopped proper management by grazing and burning. Read about it in Firestick Ecology published by Connor Court.

Yes maybe? But given acquired immunity has transferred down the generations? Some of us remain naturally immune?

That said, as long as host rats etc/etc and fleas remain, so will the possibility of yet another pandemic! Our defence remains eternal vigilance and proper vermin control! And sharp eyed medicos!
Alan B.

AIUI the term "Black Death" refers to a particular historical plague outbreak rather than the bacteria that caused it.

Whether or not plague bacteria are present in Australia now is of little consequence, as the disease is easily treatable with antibiotics.

Yersinia Pestis is common in rats, which have sufficient similarities worldwide to suggests that the majority of species may well host the bacteria.

The transfer of the disease to humans is dependent on specific circumstances such as the occupation of human hosts by the rat flea - demonstrated as being far from the preference of the rat flea (let's not be offended by the flea's choices here) and is now relatively straightforward in it's treatment, as Aidan has described.

A level of genetically transferable natural immunity, suggests we could conceivably transfer this acquired immunity, via GM? Or create with an inoculating vaccine?

Volunteers could be protected with Aidan's antibiotics? Some of which, might be deployed against depression/inflammation of the brain?

Interestingly some of this genetically transferable immunity, seems to protect against AIDS, or prevents HIV from becoming full blown AIDS?
Alan B.