A Salmonella outbreak linked to horse meat from Romania sickened 25 people in France this past year, according to a new report.

Eleven cases were men and 14 were women. They ranged from 2 to 90 years of age and the median was 68 years old.

In September 2019, the regional unit of Santé Publique France in the Hauts-de-France region was alerted to a spike in Salmonella Bovismorbificans notifications in Nord and Pas-de-Calais during the first two weeks of August, found by the National Reference Center for E. coli, Salmonella and Shigella at Institut Pasteur.

The 25 salmonellosis cases, belonging to the same genomic cluster, were identified between Aug. 4 and 26, 2019. Nine people needed hospital treatment and two had severe complications but none died.

Hypothesis from patient interviews
Twenty people were interviewed. Results of a food survey revealed consumption of chilled raw or undercooked minced (ground) horse meat by 18 of 20 cases questioned in the days before onset of symptoms. No other food was eaten by all those interviewed.

Of the two people who did not eat horse meat, one person was infected with a strain having genetic characteristics slightly different from the other cases and the other was sick after eating a Bolognese pizza in a restaurant.

Consumption of horse meat has decreased significantly in France in recent decades but most of those who eat it live in Hauts-de-France. Horse meat is mainly imported from Italy, Romania, Poland, the United States or South America despite some domestic production.

Symptoms lasted for two to 21 days with a mean duration of 10 days and the mean length of hospital stay was eight days, ranging from three to 21 days.

The investigation identified a common Belgian wholesaler, supplied by a slaughterhouse and a meat cutting workshop in Romania. Batches of implicated horse meat were also distributed to Austria, Germany, Italy, Luxembourg, Netherlands, Slovenia, Sweden and Vietnam.

At the European level, none of the 14 countries which replied to the French alert about the increase in Salmonella Bovismorbificans cases observed any recent rise in infections belonging to the same genomic cluster as the French cases.

Involvement of Belgium and Romania
The fact that most purchases were made on markets made it easier to identify the buying dates and time of consumption. Four distributors obtained carcasses or pieces of horse meat from the same wholesaler of fresh meat in Belgium.

Dates of purchases cited by those sick and analysis of purchase orders and invoices provided by the distributors, made it possible to link the dates of purchase to the raw materials used and with several batches of horse meat, from a slaughterhouse and cutting workshop in Romania.

Controls were carried out in the places of purchase or vehicles cited by those ill and analyzes were done on equipment and pieces of meat, available at the time of inspections but different from batches sold during the outbreak. Salmonella Bovismorbificans was not found in the meat tested.

It was not possible to confirm the hypotheses by finding strains of Salmonella Bovismorbificans in meat consumed by cases, due to the absence of leftovers from implicated lots. The exact origin of the contamination of the meat suspected of causing the outbreak has not been found.

The outbreak was the fourth due to consumption of horse meat documented in recent years. The others in 2003, 2006 and 2010 involved Salmonella Newport, Salmonella Meleagridis and Salmonella Typhimurium.

In 2018, a Salmonella Enteritidis outbreak in France was suspected to be caused by chilled horse meat from Belgium, processed in Romania, with raw material from Hungary. Austria, Germany, Italy, Luxembourg, Netherlands, Sweden and Switzerland were also part of this alert.

In France, Salmonella Bovismorbificans is rarely isolated from humans with less than 50 cases identified, respectively in 2016 and 2017.

Officials said prevention of foodborne infections requires a change in risky eating habits. It involves informing vulnerable people about the risks of consuming raw or undercooked ground meat were contamination will not be destroyed if there is insufficient cooking.