There is a strong consensus that Yersinia Pestis was the pathogen responsible for the medieval Pandemic referred to as the "bubonic plague" or "Black Death." Twigg and various scholars (primarily in the 1970's) claimed that this particular pathogen was not responsible because the pandemic spread too quickly and blamed Anthrax and other sources, but their work was largely built on medical research which was outdated in the 1970's or has been refuted since. One of the effects of the post 9/11 fear of biological attacks by terrorists was a glut of funding for research into Y. Pestis, which discovered that both the pathogen and it's various vectors (fleas, rodents) are much more robust that Twigg assumed in making his argument.

Recently archaeologists have been able to empirically refute these "alternative pathogen" theories by doing genetic analysis of the tooth pulp of skeletons recovered from plague pits (mass burial sites) from both the 6th and 14th century pandemics. Repeatedly confirming that the victims died from some strain of Y. Pestis.

Localized outbreaks continued for centuries after the initial pandemic, eventually ending as rodent and human populations became disease-resistant or because or changing climactic conditions. The reasons are not well understood.

What could they have done better? In the fourteenth century very little. Most of the population lived in rudimentary one-room houses in which their animals and livestock often lived or slept. Y. Pestis can infect a wide range of animals (dogs, cats, pigs, chickens) and can be transmitted by both fleas, common lice. Without modern housing or sanitation medieval humans had little way to prevent exposure to or the spread of the disease. Fourteenth century medicine was mostly superstition, and for the tiny minority of people that could afford a "doctor" the medical care they could receive would have no medical benefit or be genuinely harmful (e.g. bloodletting).

It is true that real wages increased (effectively doubling) and prices for some things went down. The mortality rate is contested, but for England, where we have the best data, it is believed 55-60% of the population died in the initial Pandemic (1347-1351). In real terms this caused a massive shift of economic power from landholders to laborers, in a sense the wealthy were now competing for labor, rather than the usual situation where labor competes for jobs. This famously caused Edward I to issue the statute of laborers in 1351, establishing wage controls and attempting to restore the economic power of the nobility.

The sixth century plague pandemic caused the East Roman/Byzantine Emperor Justinian to issue a remarkably similar edict on wage and labor controls, also in response to economic changes caused by a Yersinai Pestis pandemic.

How the plague affected the culture goes beyond my knowledge.