An outbreak of Salmonella linked to a traditional meal containing meat affected more than 20 people earlier this year in Wales.

Public Health Wales was notified about two cases of salmonellosis in late July, according to a presentation at the ESCAIDE conference, organized by the European Centre for Disease Prevention and Control (ECDC).

Both belonged to the Sudanese community who bought lamb to barbecue in a park in Cardiff in July to celebrate the Muslim festival Eid-al-Adha.

Further investigations found of 33 people who attended the barbecue, 22 were identified as patients. Seven were confirmed as infected from Salmonella Typhimurium.

Nine people reported attending A&E, four were admitted to hospital overnight and one patient to intensive care. The outbreak also drew attention to a wider ongoing cluster across the UK, which is still under investigation.

Offal and lamb link
Sequences from 11 raw sheep meat samples purchased for the barbecue but not used were identical, and matched those from human samples.

Epidemiological evidence indicated that lamb meat was the food vehicle, with a greater risk of illness in those eating “marrara” a traditional Sudanese appetizer of marinated raw sheep’s liver.

There was a high risk of cross contamination as some people had used the dip from the marrara with their barbequed lamb. The raw offal and lamb were prepared in the same kitchen, washed in the same sink and stored in one refrigerator.

Consumption of raw or undercooked meat and offal is an ongoing public health issue, said officials.

Adapting health protection messages and improving awareness in minority communities who consume such traditional items either regularly, or during religious or cultural events, may help reduce the risk. Targeted communication with the affected community, including setting up food hygiene workshops are planned.

Experts added that future outbreak investigations involving minority communities should consider dishes other than those on routine questionnaires.

STEC in Wales
Another presentation looked at trends in Shiga Toxin-Producing E. coli (STEC) other than O157:H7 in Wales from 2015 to 2019.

In August 2018, hospital labs in Wales implemented a multiplex PCR test on all fecal samples to detect Shiga toxin (stx) genes, which enabled identification of all STEC serotypes.

Sequences were available for 160 non-O157 STEC patients and 153 O157:H7 infections from 2015 to 2019.

Between 2015 and 2017, three non-O157 STECs were identified, compared to 38 in August to December 2018 and 114 in 2019. The most commonly identified non-O157 serotype was O26:H11 with 38 followed by O146:H21 with 19. A total of 49 different non-O157 serotypes were detected from 2015 to 2019.

Also, 19 of 20 non-O157 isolates with stx2a and eae genes, which are associated with increased risk of Hemolytic Uremic Syndrome (HUS), were identified in 2018 and 2019.

Using the PCR assay technique increased the number of non-O157 STECs identified in Wales by 175 percent.

It enabled rapid diagnosis of clinically severe non-O157 cases and early detection of outbreaks with insights into sources and transmission of the pathogen, which can help inform public health action.