Editing Neanderthal extinction (section)

===Parasites and pathogens===
Infectious diseases carried by ''Homo sapiens'' may have passed to Neanderthals, who would have had poor protection to infections they had not previously been exposed to, leading to devastating consequences for Neanderthal populations. ''Homo sapiens'' were less vulnerable to Neanderthal diseases, partly because they had evolved to cope with the far higher disease load of the tropics and so were more able to cope with novel pathogens, and partly because the higher numbers of ''Homo sapiens'' meant that even devastating outbreaks would still have left enough survivors for a viable population.<ref>{{cite book|last=Kennedy |first=Jonathan  |title=Pathogenesis: how Germs Made History|pages=42–43 |publisher= Torva|location =London, UK |year=2023|isbn=}}</ref> If viruses could easily jump between these two similar species, possibly because they lived near together, ''Homo sapiens'' might have infected Neanderthals and prevented the epidemic from burning out as Neanderthal numbers declined. The same process may also explain ''Homo sapiens''' resilience to Neanderthal diseases and parasites. Novel human diseases likely moved from Africa into Eurasia. This purported "African advantage" remained until the agricultural revolution 10,000 years ago in Eurasia, after which domesticated animals surpassed other primates as the most prevalent source of new human infections, replacing the "African advantage" with a "Eurasian advantage". The catastrophic impact of Eurasian viruses on Native American populations in the historical past offers a sense of how modern humans may have affected hominin predecessor groups in Eurasia 40,000 years ago. Human and Neanderthal genomes and disease or parasite adaptations may give insight on this.<ref>{{Cite journal |last1=Houldcroft |first1=Charlotte J. |last2=Underdown |first2=Simon J. |date=July 2016 |title=Neanderthal genomics suggests a pleistocene time frame for the first epidemiologic transition: Neanderthal Infectious Diseases Genetics |url=https://onlinelibrary.wiley.com/doi/10.1002/ajpa.22985 |journal=American Journal of Physical Anthropology |language=en |volume=160 |issue=3 |pages=379–388 |doi=10.1002/ajpa.22985|pmid=27063929 }}</ref><ref name="Greenbaum-etal">{{Cite journal|last1=Greenbaum|first1=Gili|last2=Getz|first2=Wayne M.|last3=Rosenberg|first3=Noah A.|last4=Feldman|first4=Marcus W.|last5=Hovers|first5=Erella|last6=Kolodny|first6=Oren|date=2019-11-01|title=Disease transmission and introgression can explain the long-lasting contact zone of modern humans and Neanderthals|journal=Nature Communications|language=en|volume=10|issue=1|pages=5003|doi=10.1038/s41467-019-12862-7|issn=2041-1723|pmc=6825168|pmid=31676766|bibcode=2019NatCo..10.5003G}}</ref>

Infectious illness interactions may express the prolonged period of stagnation before the modification, as per disease ecology. Mathematical models have been used to make forecasts for future investigations, giving information about inter-species interactions during the shift between the Middle and Upper Paleolithic eras. This can be useful given the sparse material record from this time and the potential of DNA sequencing and dating technology. Such modeling, together with modern technology and prehistoric archaeological methodologies, may provide a fresh understanding of this time in human origins.<ref name="Greenbaum-etal" />

In late-20th-century New Guinea, due to cannibalistic funerary practices, the [[Fore people]] were decimated by [[transmissible spongiform encephalopathies]], specifically [[Kuru (disease)|kuru]], a highly [[virulent]] disease spread by ingestion of [[prion]]s found in brain tissue. However, individuals with the 129 variant of the [[PRNP]] gene were naturally immune to the prions. Studying this gene led to the discovery that the 129 variant was widespread among all modern humans, which could indicate widespread cannibalism at some point in human prehistory. Because Neanderthals are known to have practised cannibalism to an extent and to have co-existed with modern humans, British palaeoanthropologist Simon Underdown speculated that modern humans transmitted a kuru-like spongiform disease to Neanderthals, and, because the 129 variant appears to have been absent in Neanderthals, it quickly killed them off.<ref name=underdown2008>{{cite journal |first=S. |last=Underdown |year=2008 |title=A potential role for transmissible spongiform encephalopathies in Neanderthal extinction |journal=Medical Hypotheses |volume=71 |issue=1 |pages=4–7 |doi=10.1016/j.mehy.2007.12.014 |pmid=18280671}}</ref><ref>{{cite journal |last1=Liberski |first1=P. |title=Kuru: a journey back in time from Papua New Guinea to the Neanderthals' extinction |journal=Pathogens |volume=2 |issue=3 |pages=472–505 |year=2013 |pmid=25437203 |pmc=4235695 |doi=10.3390/pathogens2030472 |doi-access=free}}</ref>