@TrailingLoellia
Yes - did you ? Literally the first two paragraphs.
"We inevitably associate malaria with tropical climates where the vector Anopheles mosquitoes are abundant. In 2017, there were an estimated 219 million cases worldwide, predominately in sub-Saharan Africa and India, resulting in 435 000 deaths.1 Often forgotten is that malaria is widely believed to have been formerly endemic to the UK. The last outbreak involving locally acquired cases occurred between 1917 and 1921. Could vector-borne disease pose a threat today?"
"Febrile-like illnesses, probably malarial in origin, were historically common in lowland marshland areas. Known variously as ‘marsh fever’, ‘agues’, or ‘tertian fevers’, these illnesses affected areas of low-lying Essex, Sussex, Kent, the Somerset levels, the Yorkshire Holderness, and the Lancashire Ribble Valley.2 These were likely caused by Plasmodium vivax or Plasmodium malariae, and were probably transmitted by the native mosquito Anopheles atroparvus. By the 20th century, such indigenous malaria was becoming rare, banished by land drainage and better housing."
My original post said "likely to have been endemic" for a very good reason.