Tourists stroll on the Trocadero square, in front of the Eiffel Tower during a rainy day in Paris, France, May 30, 2016. REUTERS/Charles Platiau

London - Tourists travelling to France have been warned to watch out for an unlikely threat – diseased chipmunks.

The rodents, which have soared in number, carry ticks which spread Lyme disease, a chronic infection that attacks the nervous system.

There are around 150 000 of the animals, currently living in France, with more than 10 000 estimated to inhabit the Senart forest south of Paris alone.

Popularity of the chipmunks as pets rose after the success of 2007 movie Alvin and the Chipmunks. But after children tired of them, many have been abandoned.

The animals are particularly dangerous because they are not afraid to approach humans, increasing the risk of exposure.

Up to 1 000 of them are thought to be in South East England, having spread to the UK via the Channel Tunnel.

The ticks, which are hosts for the bacteria Borrelia bacterium, can be found lurking in woodland, and feed on the blood of birds and mammals.

Symptoms of Lyme disease include flu-like symptoms such as tiredness, muscle pain, headaches and stiffness.

If left untreated, more serious symptoms may develop including facial paralysis, memory problems and difficulty concentrating.

Nature expert Guy Bruel said: ‘There is a particular problem in the woods around Paris, attributed mainly to people who bought the animals as family pets then got rid of them.

“This is just the behaviour that will lead to the chipmunk getting to Britain in huge numbers.’

Jean Louis Chapuis, an expert on rodents warned: “Lyme disease is a terrible condition, and the chipmunks are a major carrier. These rodents are not shy, and in fact are very approachable.”

Daily Mail