Monkeypox: we cannot afford to ignore yet another warning

An unintended consequence of smallpox eradication and ending the smallpox vaccination campaign has been to render the global human population immunologically naïve to orthopoxvirus infection for the first time in history. This has occurred at a time when the majority of people worldwide live in high population densities in cities and when connectivity across the world has never been higher, both of which facilitate the emergence and spread of infectious diseases. It is not surprising, therefore, that novel zoonotic orthopoxvirus infections have been increasing in recent years, or that an international outbreak of human monkeypox disease has occurred. A One Health approach, including consideration of land-use change and the bushmeat and exotic pet trades, is required to prevent opportunities for the emergence of monkeypox, or diseases cause by other orthopoxviruses, and for a rapid and effective response to any outbreaks in order to limit their spread.