France on alert after outbreak of West Nile fever

West Nile fever, the mosquito- borne disease that has terrorised New York in the past year, is believed to have killed 15 Camargue horses in the south of France in recent weeks.

West Nile fever, the mosquito- borne disease that has terrorised New York in the past year, is believed to have killed 15 Camargue horses in the south of France in recent weeks.

Although no case of human infection has been recorded, the local authorities are taking no risks. A large programme ofextermination of mosquitoes and rats has been ordered in the marshlands known as the "Petite-Camargue", west of the Camargue wetlands proper in the delta of the Rhone.

The French government has also called on anyone living in the area - or who has passed through in recent weeks - to consult a doctor immediately if they fall ill with "flu-like symptoms".

The outbreak - the first in France for 34 years - is believed to have started with a bird from one of a dozen species that migrate regularly, or stray accidentally, between Africa and the French Mediterranean coast. The West Nile fever virus passes from mosquitoes to birds and back to mosquitoes in a permanent cycle but can sometimes spread through mosquito bites to humans and other mammals.

The disease can be fatal to children and the elderly and has killed seven people in New York since last summer. Another 52 people have fallen seriously ill, provoking the city's tabloid press to describe the cases as a "plague" and a health "catastrophe". The Mayor of New York, Rudolph Giuliani, ordered a vast mosquito eradication programme, including the spraying of the city by helicopters, which caused, in its turn, another health scare.

Four horses are positively confirmed to have died from the disease in the past three weeks near the town of Lunel in the Hérault département, just east of Montpellier. Three other horses are strongly suspected to have died from the virus; six other possible cases, including two in the Gard département slightly to the north, are being investigated.

West Nile fever has an incubation period, from the initial mosquito bite, of between three and 15 days. In many people the symptoms are mild or hardly detectable. Other people, especially infants and people aged over 60, can fall ill with a high fever, severe headaches and vomiting.

The Prefect (the senior national government representative) of the Hérault has ordered an intensive programme of eradication of mosquitoes and rats in the marshes of the Petite-Camargue. He has also advised people living in, or visiting, the area to take action to protect themselves from mosquitoes, including wearing long-sleeved clothes and using insect-repellents out of doors and insecticides in their homes.

The last outbreak of West Nile fever in France was in 1966, also in the Camargue, when 20 horses died.