After circulating in several communes in Var in August, then in Vauvert in Gard at the beginning of September, the West Nile virus was identified in Hérault.
:quality(50)/2023/07/07/64a7df4c5fe71_placeholder-36b69ec8.png)
Published
Reading time: 3 min
:quality(50)/2024/09/09/moustique-66df22709421d504058065.jpg)
An indigenous case of the West Nile virus has been identified in Baillargues in the metropolitan area of Montpellier, France Bleu Hérault learned from the department’s prefecture on Monday, September 9. This is the first time that the Hérault department has officially confirmed an indigenous human case of the West Nile virus since 1962 and the start of surveillance of this disease by the French authorities. In total, France has had 16 indigenous human cases, i.e. caused by an infected mosquito circulating in France, since the beginning of 2024: this new case identified in Hérault, 12 cases in Var from mid-July to the end of August, one case in Guadeloupe in early August, and two cases in Gard in late August.
After circulating in several towns in Var in August, then in Vauvert in Gard at the beginning of September, the West Nile virus has been identified in Hérault. The resident of Baillargues who contracted the disease was hospitalized. His state of health is now stable, the Hérault prefecture indicated in a press release. Three horses have also tested positive for the West Nile virus, two of them have died. Four other suspicions of equine contamination have been identified.
According to data known to health authorities in 2024, 80% of West Nile virus infections are asymptomatic. In 20% of cases, the patient presents with a “flu-like syndrome (fever, aches, headaches)”. And in less than 1% of infections, there may be neurological complications, especially in immunocompromised subjects.
The virus is transmitted by mosquitoes of the genus Culex, the common mosquito in France which feeds mainly in the evening and at night, to be differentiated from the tiger mosquito (Aedes albopictus) which feeds during the day. “Culex mosquitoes are infected exclusively through contact with infected birds”specifies the regional health agency of the Paca region. “Humans and horses are ‘accidental hosts’ of the virus. There is no transmission of the virus from human to human (or from horse to human) via mosquitoes.”
The virus is being actively monitored on the Mediterranean coast and in New Aquitaine, but also in the overseas departments with a first human case identified on August 7 in Guadeloupe. “The West Nile virus is considered today to be the second most widespread flavivirus after dengue fever.”recalled the regional health agency of Guadeloupe. No epidemic has been recorded in Reunion or Mayotte, “but the virus is circulating endemically in Madagascar”adds Public Health France, with an isolated case also identified in Mayotte in 2021.
In 2023, in mainland France and Corsica, 43 human cases of indigenous infection were identified in three regions: 33 cases in Nouvelle-Aquitaine (26 cases in Gironde, 5 cases in Charente-Maritime, 2 cases in Charente); 2 cases in Corsica; 8 cases in Paca (3 cases in Alpes-Maritimes, 3 cases in Bouches-du-Rhône, 2 cases in Var).
According to Public Health France, the virus was first detected in 1962 in mainland France with human and equine cases in the Camargue. It reappeared in the early 2000s, in the Camargue, Var and Pyrénées-Orientales (5 equine cases in 2005). In 2023, human cases were identified for the first time in Nouvelle-Aquitaine (in Gironde, Charente-Maritime and Charente), after equine cases were recorded in Gironde in 2022. In total, in 2022, six human cases were recorded in mainland France (and Corsica): four cases in Var and two cases in Haute-Corse.