[3] Other suggested causes include the emergence of communicable diseases spread from animals living in close quarters with humans.
[2] The population increase between 5950 and 5550 BP (4000 to 3600 BC) that preceded the decline was catalysed by the introduction of agriculture,[4][3] along with the spread of technologies such as pottery, the wheel, and animal husbandry.
[2] After the Neolithic decline, there were massive human migrations from the Pontic–Caspian steppe into eastern and central Europe, beginning approximately 4800 BP (2850 BC).
[2] An ancient version of the Yersinia pestis has come up from multiple skeletal studies throughout Eurasia, skeletons which have dated back to around the estimated periods of the Neolithic Decline.
One 5,000-year old individual buried in Riņņukalns, Latvia, was infected with an early Yersinia pestis strain, shortly after it split from its antecessor Y. pseudotuberculosis c. 7,000 years ago.
[7] A tomb in modern-day Frälsegården in Gökhem parish, Falbygden, Sweden, contained 79 corpses buried within a short time of one another about 4,900 years ago.