[alexander_busek]

The vast majority of cases involved bubonic plague, with the exception of five instances of pneumonic plague and two instances of septicemic plague, which occur when the disease [i.e., the bubonic plague] spreads to the lungs or blood, respectively.

You know, I'd hardly call those five instances of the bubonic plague spreading to the lungs or blood "exceptions." I'd say that all of those cases, without exception, involved the bubonic plague.

Regards,

[SoCal Pubbie]

While all three spread the same batería, the difference is the mode of transmission. Bubonic plague is spread by animal bites, pneumonic plague thru airborne droplets. It goes person to person and is much more deadly. It’s what made the Black Death so nasty. There are usually no swollen lymph nodes, called “buboes” hence not bubonic plague.