Health chiefs in Bradford are trying to trace the source of a food poisoning bug which has affected 130 people.
Some of the victims are being treated in the Bradford Royal Infirmary suffering for dehydration caused by sickness and diarrhoea.
In a statement the Bradford District Health Protection Unit said the outbreak had been growing over the last four days, but was now subsiding.
It said 130 cases had come to their attention, with 46 needing hospital treatment in Bradford.
Another three people are being treated elsewhere in West Yorkshire, but the victims are thought to have possible links to the outbreak in Bradford.
Experts from the protection unit say that while early results suggest the illness may been caused by a strain of salmonella, further tests are being carried out.