Norway's largest Salmonella outbreak in decades possibly linked to organic alfalfa sprouts
The Norwegian Institute of Public Health has confirmed that 230 people have been infected in the Salmonella outbreak, but the peak of infection has been reached. The suspicion that organic alfalfa sprouts are the source of infection has been further strengthened.
This is the largest salmonella outbreak reported in Norway in almost 40 years, says acting section manager Umaer Naseer at infection control and emergency preparedness at the Norwegian Institute of Public Health.
The increase in the number of infected people has been large since December 6, when we last reported on the outbreak . This is not unexpected as it takes time from sampling of those who have become ill to the final results of the laboratory analyses. Most of the infected people became ill in the transition between November and December 2024, around the time of the withdrawal of organic alfalfa sprouts, says Naseer.
The infected people have become ill from mid-October to mid-December. They are aged 0–90 years, the median age is 47.5 years, and 159 of them are women. 76 of the infected have been hospitalized. The infected are residing throughout the country: Vestland (72), Akershus (24), Trøndelag (19), Oslo (18), Innlandet (15), Møre og Romsdal (13), Rogaland (12), Telemark (11), Vestfold (11), Østfold (11), Agder (7), Buskerud (7), Finnmark (5), Troms (3) and Nordland (2).
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There are mainly two types of Salmonella that are the cause of the outbreak: Of the 230 infected people, 105 are infected with Salmonella Newport and 120 are infected with Salmonella Typhimurium. The last 5 are infected with other types of Salmonella.
The suspicion of alfalfa sprouts as a source of infection in the outbreak has been further strengthened since we now see that the number of infected people has decreased after the sprouts were withdrawn from the market and Salmonella was found in the sprouts, says Naseer.
The Norwegian Food Safety Authority and the Norwegian Veterinary Institute have detected the same salmonella bacteria in sprouts that the laboratory at the Norwegian Institute of Public Health has detected in patients.
Naseer points out that sprouts are a known risk product for gastrointestinal infections. Pregnant women, immunosuppressed people, and young children should therefore avoid eating raw sprouts.
Several countries in Europe have had outbreaks of Salmonella linked to the consumption of sprouts in recent years. The European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) are now working with authorities in Norway and other European countries to investigate whether there is a link between these outbreaks and measures that should be taken to prevent similar outbreaks in the future.