[West Nile virus: in France again, in humans and horses].

The research article discusses the recurrence of the West Nile virus (WNV) in France, affecting both humans and horses. Its spread is mainly driven by mosquitoes, particularly the Culex species, with an increasing rate of central neurological complications and higher mortality rates among older people.

Background on West Nile Virus (WNV)

• West Nile virus (WNV) is a commonly observed arbovirus that is primarily transmitted by mosquitoes, particularly the Culex species.
• The virus usually causes epidemics in humans and certain livestock, specifically horses, in sub-Saharan Africa.
• There have been occasional reports of WNV infections in Southern Europe and some Mediterranean countries.

Changing Clinical Aspects of WNV

• Since 1994, the clinical aspects of WNV appear to have shifted towards increasing central neurological involvement and a higher mortality rate.
• The mortality risk is particularly elevated for individuals over the age of 50.
• In 1999, WNV made its way to New York, causing severe clinical symptoms there.

WNV Spread in North America

• The virus spread across nearly all of North America within four years, with only four states in the United States remaining free from the virus.

WNV Resurgence in France

• In the wake of an equine epizootic in Camargue, France in 2000, French medical authorities initiated a survey to monitor the spread of WNV in the southern regions of the country.
• This initiative allowed the identification of six human WNV cases in 2003 along the French Mediterranean coast, which was previously considered free from the virus. Notably, no cases were found in Camargue during that period.