Holidaymakers who are heading to Greece this summer are being warned to take precautions against a mosquito-borne disease which infected 316 people last year and killed 50, a record.
The Foreign Office has already issued advice to tourists about West Nile virus, saying: "There were more than 300 cases ... in Greece in 2018. You should consider preventative measures to minimise exposure to mosquitoes, for example using mosquito repellent when outdoors and closing doors or windows or using screens."
The virus is transmitted by the insects after they have fed on the blood of infected wild birds, and causes headaches and fevers. In some cases it can be fatal.
"There have been enough cases to know that this is now a public health issue," public health official Danai Pervanidou told The Guardian.
"The virus has established itself in Greece through migratory birds and we are recommending that everyone takes personal protective measures such as wearing long sleeves, avoiding places with stagnant water and using mosquito nets and repellent."
Almost 2.4 million Britons visit Greece every year, making the UK the third highest provider of tourists after Macedonia and Germany.
Tourism makes up a quarter of the country's gross domestic product and numbers of visitors topped 30 million last year. The government is keen to curb the spread of the virus from rural areas to tourism hotspots.
"It is impossible to predict the area of virus circulation because of its complex epidemiology but what we do know is that it has moved from villages and wetlands in rural areas to big urban centres, including the Attica region [around Athens] and Thessaloniki," Pervanidou told the Guardian.
"Just as in winter when we expect an outbreak of influenza, in summer we now have to expect cases of West Nile fever. We have to be prepared."
There have also been increases in reporting of the disease in other Mediterranean countries, including Italy, Cyprus, Romania and Serbia.