Table 1.

Prehistoric extinctions attributed to infectious disease.

extinction event	hypothesis/argument in favour proposed by authors	objection
moa [28]	genetic evidence suggests that there were at least 3–12 million moa 1000 years ago and decline occurred before human settlement. Disease introduced by migrant birds from Australia may have caused decline to the approximately 160 000 moa present at the time of human settlement	no direct evidence of the presence of a virulent infectious disease. Why would migrant birds bringing disease have arrived only as recently as 1000 years ago?
dinosaurs [29]	endothermic vertebrates are relatively resistant to fungal diseases in comparison with ectotherms and elevated environmental temperature can clear fungal infections in ectotherms. Events at the K-T boundary may have led to a massive fungal proliferation	no direct evidence. Is the assumption that most dinosaurs were ectothermic correct?
Neanderthals [30]	after Neanderthals had persisted in Europe for 200 000 years, anatomically modern humans eliminated them 28 000 years ago, after the arrival of modern humans 40 000 years ago. Perhaps modern humans brought in infectious agents with which they had co-evolved in Africa	no direct evidence. 15 000 years of coexistence would appear unlikely if epidemic disease was responsible for Neanderthal extinction
Late Quaternary extinctions, especially North American mega-fauna [31]	‘hyperdisease’ transmitted from humans or their commensals has led to extinction in numerous species. Such a hyperdisease should have one or more reservoir species, potential for causing infection and very high mortality in ‘new hosts’, but not to seriously threaten humans. Large bodied species were particularly vulnerable because low reproductive capacity reduced ability to recover from epidemics	no existing disease meets the necessary criteria and there is no evidence for size-based declines or extinctions in modern multi-species epizootics such as West Nile virus and avian malaria in Hawaii [32]. Rapid extinctions within a few generations of human contact would be expected, but has not been observed [33]