In 2008, 3,700 people were registered to be sick with salmonella. Statens Serum Institut estimates that the actual figure is probably 10-20 times higher because many do not seek medical help.
Salmonella is widespread in nature and in the fertiliser of many livestock. It spreads from fertilisers to animals, carcasses, raw milk, soil, water and crops. Salmonella also transmits from hen to eggs and the chicken is thereby infected when it hatches. Humans are infected through these sources, usually via food contaminated with the bacterium.