BBC News Online: World: Europe

West Nile fever hits France

The Camargue region in the south of France is suffering from an outbreak of West Nile fever - the first time the disease has affected this part of the Mediterranean in 40 years.

So far only horses have been struck by the disease, but public health experts are worried that it could spread to humans too.

The magnificent horses, famed for being able to roam freely, are being rounded up.

So many animals have died and been infected that the public health authorities have been forced to introduce emergency measures.

One horse owner, Bernadette Puig, has already lost one horse from her small herd.

"We found her lying in the field unable to get up," she said. "We didn't know what the problem was.

"By the time the vet arrived she was dead."

Spreading disease

The virus causes paralysis. Horses cannot even shake their heads to get rid of the flies. The horses that live have to be slowly taught how to walk again.

"It's very difficult because some people cannot bring them to the clinic," said vet Eric Maerten. "It's very difficult to care for them in the field."

The disease has been brought to the Camargue by migratory birds. Mosquitoes bite the birds, the birds then land on a horse's back and the mosquito bites the horse. The result has been devastating.

With global warming, the expectation is that the disease will be more frequent, and the worry for the health authorities is that it could soon affect humans as well as horses.

At the world famous Pasteur Institute in Paris this is a threat that is being taken very seriously indeed.

"The virus can produce some disease in humans, producing most often a flu-like illness, a very mild form of disease. But in a very few cases we have more neurologically severe forms," said Professor Herve Zeller.

It is hoped a cold winter will kill off the mosquitoes. In the meantime the swamps and lagoons are being sprayed.

The fear, though, is that this is a problem that will be back next year.