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The National Institute of Public Health has investigated a national outbreak with Salmonella Enteritidis infection. So far, 13 confirmed cases of infection have been found over 3 years (2019-2021), and the last time in a sample taken in September 2021.

Image/Robert Herriman

The samples are completely genome-sequenced and show the same genotype. The same genotype of  S. Enteritidis has also been found in a sample from a snake that the Veterinary Institute has analyzed.  

Those who have snakes, or other reptiles as a hobby or pet, should take extra precautions and always wash their hands after handling and feeding the animals to avoid getting sick with salmonellosis. 

The National Institute of Public Health has so far interviewed 12 of the 13 people who were infected with  Salmonella  and eight of these have had either direct or indirect contact with snakes, while four of them have not had contact with snakes / reptiles.  

Epidemiological investigations and whole genome sequencing have confirmed the connection between the  Salmonella outbreak in humans and contact with reptiles, says senior adviser Heidi Lange at the National Institute of Public Health. 

Same outbreak strain as in the UK 

The outbreak in Norway is caused by the same  S . Enteritidis bacterium found in an outbreak from the UK linked to  Salmonella -infected mice and rats used as feed for reptiles. The outbreak in the UK stretches from several years back in time to the present day and includes close to 850 people, most of whom kept reptiles as pets: 

The outbreak in the UK emphasizes that one should also pay attention to the fact that the feed for reptiles (for example rodents such as frozen mice) can be contagious.   

The feed is a suspected source of Salmonella in the snakes 

In Norway, FHI and the Norwegian Food Safety Authority are further investigating which feed reptile owners have used and which supplier the feed comes from. Freezing does not kill  Salmonella  so handling raw or frozen and thawed pet foods, such as mice or rats, will pose a risk of salmonellosis if the animals are already carriers of  Salmonella . Companies that sell feed in Norway are responsible for ensuring safe feed, and there is a requirement for the absence of salmonella in the feed.   

– We recommend that those who handle reptiles and feed them always wash their hands well with water and soap after contact with the animals, their food or with their terrariums / aquariums. Gloves can also be used when handling feed and cleaning, but the hands should in any case be washed well with warm water and soap after feeding, says Heidi Lange.  

She further points out the importance of ensuring that children in houses where reptiles are kept as pets wash their hands well after contact with reptiles and before eating food. This applies even if they do not touch the animal directly. 

About salmonella in reptiles 

Salmonella  are bacteria that can be found in the intestines of many animals, especially reptiles. Reptiles can be carriers of the bacteria without showing any symptoms of the disease and spread it to humans. Most reptiles carry  Salmonella  in the gut for months or years after eating contaminated feed, and the infection can spread to owners and other household members. Good hand hygiene after handling is important.  

Salmonella in humans 

Although a  Salmonella infection in humans usually causes short-term illness, with diarrhea, fever, vomiting and abdominal pain, more serious illness may occur that may require hospitalization. 

If you have symptoms of salmonellosis, you should wash your hands regularly and avoid cooking for others. If you work with food  (for example in a commercial kitchen or canteen) or with particularly vulnerable patients  , you should not perform your ordinary work until the symptoms are over and there are 2 culture-negative stool samples.