By the time the vet arrived she was dead. 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. 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. It is hoped a cold winter will kill off the mosquitoes.