11 November 2004

NI salmonella outbreak declared over

A recent outbreak of salmonella infection reported across Northern Ireland has now ended, according to health authorities.

The outbreak was associated with the presence of an unusual strain of the bacterial infection, Salmonella Newport, that may have been present in lettuce. The outbreak resulted in 121 confirmed and 10 suspected cases of the illness since the beginning of September.

Similar outbreaks, some with an association with lettuce, were reported in other parts of the UK during the same period.

Most cases of illness in Northern Ireland were reported during September, with the last recorded case being in mid-October. Work by the investigation team showed that lettuce had been eaten by most people prior to their sickness.

Dr Brian Smyth, of the Communicable Diseases Surveillance Centre, who led the Northern Ireland investigations, said that while lettuce remained the most likely cause of the outbreak, it had not so far been possible to pinpoint the source.

“The circumstances would suggest there has been a contaminated batch of lettuce distributed across Northern Ireland,” said Dr Smyth. “While we analysed many samples of lettuce during the outbreak, we were unable to detect salmonella from these.

“This would indicate that the organism was carried in some lettuce for a limited period of time and has now left the food chain.”.

The investigation team comprised Dr Smyth’s organisation, the four health and social services Boards and environmental health services from District Councils.

(MB/SP)