WEST NILE VIRUS – New update on cases in Hérault
West Nile virus infection is transmitted by mosquitoes (primarily of the genus Culex) that become infected by biting infected wild birds. Horses, and sometimes humans, are “accidental hosts” that can become infected with West Nile virus when bitten by infected mosquitoes but cannot transmit the virus themselves.
In Hérault, the analyses carried out confirm, to date, the contamination of 14 horses by the West Nile virus in the municipalities of Marsillargues, Lattes, Mauguio, Lansargues and Lunel-Viel. New suspicions in progress in the department and confirmed cases of horses infected by the virus in Gard testify to the active circulation of the virus in Camargue.
The disease manifests itself in equines either in a pure febrile form, often inapparent, or in a nervous form (dejection, tremors, neurological disorders). Spontaneous recovery generally occurs in 3 to 4 weeks, but severe forms with paralysis and death can occur.
A first human case positive for West Nile has been diagnosed in Baillargues. The health of this person is now stable. A new positive case has been detected in Lattes.
In most cases, human infection with West Nile virus is asymptomatic, meaning that the patient does not present any symptoms. In some cases, the disease manifests itself as a flu-like syndrome (fever, headache, muscle pain) sometimes accompanied by a rash. The sudden onset of these symptoms should immediately result in a medical consultation, which may be followed, if necessary, by a report to the ARS.
As a reminder, the circulation of the West Nile virus is the subject of a triple surveillance system in France, in humans, horses and birds, which involves numerous partners and is currently supplemented by epidemiological and entomological surveys carried out in this sector of Hérault by teams from the ARS, Public Health France and the mosquito control operator Altopictus.
The ARS has strengthened the surveillance system by raising awareness among health establishments and professionals in Occitanie about the identification and screening of any suspected cases. Finally, measures to secure blood and organ donations are active and will remain so until the end of the risk season, in Gard and Occitanie. They are implemented by the French Blood Establishment (EFS) and the Biomedicine Agency (ABM).
The Prefect of Hérault and the Director General of the Occitanie Regional Health Agency renew their call for compliance with preventive measures, particularly in geographical areas affected by cases of infection:
·protect yourself against mosquito bites to avoid being infected: wear loose, light-coloured clothing that covers your arms and legs, apply a repellent product to exposed areas of skin, respecting the contraindications and, if necessary, protect yourself with mosquito nets in areas where mosquitoes are particularly numerous;
·fight against the proliferation of mosquitoes around the home by eliminating stagnant water which constitutes their larval breeding grounds (e.g. empty and store small containers away, cover water tanks with a cloth or mosquito net, etc.);
·for sensitive people (e.g. newborns, pregnant women, people with compromised immune systems), sleep under a mosquito net;
· immediately consult your doctor if you experience any suggestive symptoms: sudden onset of fever accompanied by headache, muscle pain, a rash, or even behavioral problems or incoherent speech.
Furthermore, the Prefect of Hérault calls for vigilance among horse owners in the affected risk areas and veterinarians in the equine sector. He reminds us of the obligation to report to the DDPP any case of a horse with symptoms suggestive of West Nile, and makes the following recommendations:
vaccinate and disinfect horses;
when possible, do not leave horses outside in the evening and at night to limit exposure to mosquitoes;
Disinsection of animal transport vehicles in the event of movement from the relevant risk areas to prevent the movement of potentially contaminated mosquitoes to disease-free areas.
