The United Kingdom has reported 24 cases of Salmonella linked to travel on cruise ships.

Salmonella Enteritidis cases are from cruise ships visiting destinations in the Eastern Mediterranean and Middle East. The outbreak was detected through whole genome sequencing (WGS) analysis. They have sampling dates from May 6 to 21, 2019. Five other cases have sample dates ranging from 2014 to 2018.

Of the 24 cases in 2019, 12 are female and the median age is 64 years with a range of 40 to 84 years old. The most commonly reported cruise ship destinations are Croatia, Corfu, Greece, Israel, Italy, Jordan, Montenegro and Oman.

A total of 717 Salmonella infections were reported from April 29 to June 2 in England and Wales compared to 367 from April 1 to 28, according to Public Health England figures.

Investigations to date indicate there is more than one cruise holiday associated with the outbreak. Patients for whom information is available said they ate all meals on the cruise ship with many spending the entire incubation period on board.

The European Centre for Disease Prevention and Control (ECDC) reported that information on whether the different cruise ships were run by the same company is not yet available.

“However, it is likely that that the same contaminated product would have been distributed to different ships. Considering that the latest reported onset of symptom was on May 21, 2019 and taking into account certain reporting delays, it is likely that additional cases associated with this event will be reported in the UK and in other EU/EEA countries able to timely perform sequencing of Salmonella Enteritidis isolates from patients with a history of travel abroad.”

So far, Denmark, Israel and Luxembourg have reported no closely related cases.