They visited Bordeaux, France, last month for the Rugby World Cup and reported  eating home-canned sardines in the same bar and restaurant

The University of Minnesota  Center for Infectious Disease Research and Policy (CIDRAP) reports that 15 cases of botulism poisoning resulted, including one death.

The deadly outbreak was confirmed by the open-access platform known as  Eurosurveillance.

CIDRAP’s summary of the botulism outbreak follows:

The report presented the clinical case descriptions of eight patients seen at the Bordeaux University Hospital, where the first patient treated in the outbreak was admitted to the intensive care unit (ICU) on Sept. 6. 

That patient required mechanical ventilation and experienced several severe symptoms, including eye drooping, impaired swallowing, and oculomotor palsy — in which the affected eye does not track correctly.

“Because of the neurological symptoms, the patient was initially treated for Guillain–Barré syndrome, but botulism was also suspected,” the report said. Over the next four days, two more patients arrived at the hospital with similar neuro-ophthalmic symptoms and required ICU care.

Home-canned sardines implicated
All three initial patients seen at the hospital reported visiting France for the rugby tournament. On Sept. 10, French investigators questioned the three, who all reported eating home-canned sardines in the same bar and restaurant in Bordeaux.

On Sept. 11 and Sept. 12, the hospital saw five more patients, all international visitors, for symptoms of botulism poisoning, including descending paralysis and extensive gastrointestinal illness.

The patients came from Canada, France, Ireland, and the United States. Two patients were men, six were women, and only one was younger than 50. The average time between the consumption of sardines and the first signs of illness was 13 hours.

“Six of eight cases required invasive mechanical ventilation because of respiratory muscle paralysis,” the CIDRAP authors said. The median delay between the onset of symptoms and intubation was 25 hours.

Six of the eight patients seen at Bordeaux University Hospital were discharged a month later, and two remained on mechanical ventilation. All eight had received treatment with botulism antitoxin.

Largest outbreak in France
Following the initial cases, the French Directorate General of Health (DGS) sent a national alert to all practitioners about the cases seen at Bordeaux, two additional cases, and one death linked to this outbreak. In total, 15 people were sickened and reported eating sardines at the same restaurant.

Though rare, botulism can be one of the most severe foodborne illnesses, often caused by inadequately processed home-canned, preserved, or fermented foods.

From 2008 to 2018, France reported 82 outbreaks of food-borne botulism, including 159 cases, and the most people involved in a single outbreak was six, making the new outbreak the nation’s largest.

Clinicians across France have been cautioned to look for symptoms of botulism in patients who have recently traveled to Bordeaux. Such symptoms include difficulty swallowing, blurry vision, slurred speech, and descending flaccid paralysis.

“Food-borne botulism can be misdiagnosed,” the authors conclude. “This report highlights the importance of promptly notifying cases with suspected botulism, as this triggers awareness and immediate investigation to determine the source and control the outbreak.”

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