With signs that 2019 will see the end of a record run of tourism seasons in Greece, visitors – as well as residents – are being warned of some perils, such as wildfires, but especially the mosquito-borne West Nile Virus, that can be deadly.

The United Kingdom’s Foreign Office issued an advisory with no reports whether Greece has sprayed for the insects yet despite an unprecedented outbreak of the disease last year, which killed 50 people.

“There have been enough cases to know that this is now a public health issue,” Danai Pervanidou who heads the office for vector-borne diseases at the national organisation for public health (KEELPNO) told the British newspaper The Guardian’s correspondent Helena Smith in Athens.

“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,” she said.

In a transmission season that began unusually early, laboratory diagnosed cases were reported in both rural and urban areas, according to KEELPNO. Many of those who contract the virus after being bitten won’t show symptoms.

About 20% experience mild, flu-like ailments including fever, headaches and general aches, only 1% will go on to develop a serious illness, according to the US Centers for Disease Control and Prevention, the paper said.

But among those diagnosed in Greece last year, 243 displayed symptoms of neuro-invasive disease such as encephalitis, meningitis and acute paralysis. Not since 2012 when there were 262 cases and 35 fatalities has an outbreak been so severe.

The US embassy in Athens issued a health alert urging citizens to take preventive measures, from cleaning up mosquito breeding areas to keeping grass and shrubs trimmed.

Some 31 million tourists are expected this year, although there were signs the numbers could fall below expectations with Greece facing more competition from countries such as Turkey, which had seen a fall-off after political instability and terrorism fears.

Greek doctors and medical professionals are passing out fliers and authorities are distributing leaflets to airports as well as municipal and regional authorities nationwide.

“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 centers, 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.”