More than 650 people have fallen ill in France this past month after eating contaminated raw shellfish.

Since the start of December 2019, Santé publique France has received 123 reports of collective food poisoning suspected to be linked to consumption of raw shellfish, mainly oysters.

The majority, 87 of the 123 alerts, occurred from Dec. 23, 2019, and forward. A peak of illnesses hit from December 25 to 27.

A total of 668 people were sick and 17 needed hospital treatment. Most are more than 15 years old. Of the 415 patients with age information available, 15 were younger than 15.

Much higher than recent years

Symptoms, mainly diarrhea and vomiting, as well as incubation times, are consistent with norovirus or other enteric virus infections. Stool tests have confirmed the presence of these viruses. Symptoms of norovirus appear one to two days after being infected and typically last for two or three days.

The number of notifications linked to consumption of raw shellfish in 2019 is significantly higher than previous years. Each year between 25 and 120 alerts caused by eating shellfish are reported to Santé publique France, of which between three and 22 occurring in December.

French authorities are investigating to traceback contaminated items to production areas and tests are carried out on the sites concerned. To date, several areas have been closed because of contamination by norovirus.

Authorities in Ille-et-Vilaine in France stopped fishing, collection, shipping and marketing of shellfish from two production areas until further notice because of norovirus. Those areas are “Baie du Mont Saint-Michel rivage” and “Zone conchylicole d’Hirel.”

Auchan and Casino, supermarket chains in France, have informed consumers of recalls this past week because of possible norovirus in products from companies including Cultimer France, La Vivière, Thaëron, Mytilimer Production and Les Viviers de Saint Colomban et Keroma. Another supermarket, Carrefour, has also issued related recalls involving firms such as Huitres Henry and Fine de Cancale.

Other countries affected

A variety of shellfish from France have also been recalled in Belgium, Luxembourg and Switzerland due to norovirus.

In Switzerland, Coop has recalled fresh oysters called “Bretagne Creuses speciale” that were sold beginning Dec. 30. Affected products have been removed from sale and consumers are advised to take them back to the store for a refund.

Migros recalled mussels called “Moules de Bouchot de la Baie du Mont Saint Michel” as they came from the Baie du Mont Saint-Michel in France wher norovirus has been detected. only the Migros store in Geneva was involved.

All dates of the product, which comes in 1.4-kilogram packs with article number 2514.227.300.00 and 700-gram packs with article number 2514.227.200.00, are affected.

In Luxembourg, Auchan sold oysters and mussels from an affected French region from the company’s Mytilimer and Cultimer. Cora also sold mussels and oysters from one of the affected harvesting areas. Follow this link for affected product names, dates and codes.

In Belgium, Match has recalled “Moules de Bouchot de la Baie du Mont Saint Michel” branded Mytilea and sold in 1.4-kilogram packs from stores in Braine L’Alleud, Fleurus and Grez Doiceau. This product has also been recalled by Cora as it was distributed to stores in La Louvière.