The NHS will start monitoring blood donations to spot early signs of tropical diseases that could spread in the UK due to climate change.
Ticks and mosquitos are being driven further north, sparking fears that viruses once specific to warmer locations will reach our shores.
Mosquitos that can carry West Nile virus have been detected in southern England and there have been four cases of tick-borne encephalitis virus likely acquired in the UK.
Usutu virus, typically seen in parts of Africa, Europe, and the Middle East, has been found in birds in the UK.
Around 5,000 samples will be taken from consenting blood donors over the next few months and checked for the three viruses.
Dr Amanda Semper, project lead at the UK Health Security Agency, said: “Infections such as West Nile and Usutu aren’t currently found in the UK, but there is an increasing risk of mosquito-borne infections in this country, driven by climate and environmental change, the globalisation of travel and trade, and changes in land use.
“This new programme will help deepen our surveillance, acting as an early warning of infections for when they do arrive here, further strengthening our ability to detect them early.”
The three diseases cause similar flu-like symptoms in humans and, in more severe cases, can lead to serious neurological illnesses such as encephalitis or meningitis.
Health chiefs said the current risk level was “very low” but tests for further emerging diseases could be added in future.
Heli Harvala, consultant medical virologist for NHS Blood and Transplant, said: “This targeted sampling of donors provides a response capability in the event of future infectious disease threats to blood safety arising from climate change.
“By combining the test results with travel and vaccination history, we can estimate how likely it is that people got their infections here or whether the antibodies might be from vaccination.
“It also provides the means to demonstrate that a virus is not present in the blood donor population, which is equally important operationally and would guide future testing strategies.”
