Health experts have warned of the “increasing risk” of some tropical infections in the UK as they launched a new way to monitor donated blood for viruses.

Concerns have been raised that some diseases that are not currently present in the UK could pose a threat in the future due to climate change.

Now NHS Blood and Transplant (NHSBT) has created a new warning system to detect newly emerging viruses potentially reaching the UK.

Researchers will examine samples taken from blood donors for tick-borne encephalitis virus (TBEV), West Nile virus and Usutu virus.

No human cases of Usutu or West Nile viruses contracted in the UK have been identified.

But Usutu has been found in birds in the UK and mosquitos that can spread West Nile virus have been recently detected in the south of England.

TBEV has been found in a small number of ticks in the UK, and four cases of TBEV infection that were likely acquired via a tick bite in the UK, have been reported so far.

While the current risk is deemed to be “very low”, NHSBT and the UK Health Security Agency (UKHSA) have identified them as viruses which could spread as climate change drives mosquitos and ticks into new regions as they experience warmer climes.

Initially, the new project will see 5,000 blood samples taken from consenting blood donors over the next few months.

These samples will be analysed for viruses alongside the donors travel history, potential exposure to infection and their vaccinations.

The “Codonet” blood sample archive will be held by NHSBT at its Oxford blood centre and will link with UKHSA surveillance programmes, which monitor the spread of these infections in the general population.

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.

This new programme will help deepen our surveillance, acting as an early warning of infections for when they do arrive here

“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.”

Dr Amanda Semper, from 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.”

Peter Simmonds, director of the NIHR Blood and Transplant Research Unit in Genomics, and a professor of virology at the University of Oxford, said: “Codonet is an archive of blood donor samples, where we will also collate their travel and vaccination history, and their exposure to ticks, mosquitos or other animals.

“This would allow us to immediately initiate targeted screening in particular blood centres or specific postcodes and obtain study samples that are appropriately consented for surveillance studies or other purposes.”

– To find out more about blood donation visit blood.co.uk or the GiveBloodNHS app or call 0300 123 23 23.