“Polio may be spreading in the UK for the first time in nearly 40 years, health chiefs warned today as they declared a 'national incident'.  Officials have found traces of a vaccine-derived version of the virus in sewage samples in parts of London and say it is 'likely' transmitting within the community.”

https://www.dailymail.co.uk/health/article-10938639/Polio-spreading-UK-time-40-years-Evolved-version-virus-London-sewage.html