Gastrointestinal infections are frequent in the Middle East region from Salmonella Typhi and other Salmonella spp., Shigella spp., Campylobacter jejuni and C. coli, rotavirus, hepatitis A virus, and parasites[1].Of all the meat types consumed worldwide, poultry is the second most consumed, and it is expected to grow fastest. As a result, poultry is a major cause of foodborne disease. Salmonella is one of the bacteria that is most frequently linked to foodborne outbreaks in poultry[2,3].
On January 7-8, 2024, Muscat’s food safety program reported an unexpected number of gastrointestinal illnesses had presented to a specific Hospital. Patients reported a similar history of eating dinner at the same restaurant of a specific club. A team from the Saudi Field Epidemiology Training Program was dispatched to confirm the existence of the outbreak, confirm the diagnosis, define, and identify the cases, identify the source of the outbreak, determine the causative agent or organism if possible, and the mode of transmission, and recommend preventive measures to be applied to prevent similar outbreaks in the future.
We conducted a retrospective cohort study. A case was defined as any person suffering from symptoms of foodborne illness (e.g. diarrhea and/or abdominal cramps, vomiting, fever ) after eating from the plated meal menu served at the specific club restaurant in Muscat on January 7 and 8, 2024. We collected information on demographics, symptoms, and food history using a semi-structured questionnaire. An environmental risk assessment was conducted to determine the source of the food contamination.
We identified 68 cases with an overall attack rate of 53% (68/128). The minimum incubation period was 10 hours and the maximum was 72 hours with a mean of 24 hours. The total number who sought medical advice was 18 (26%) among those 15 (22%) were admitted, with no death. Cases ranged in age between 9–69 years. The most reported symptoms were diarrhea (91%) and abdominal pain (65%). Illness was significantly associated with the consumption of chicken food items. Nine samples from patients were positive for Salmonella entrica. Stool cultures were negative for food handlers. Food and water samples sent for microbial analysis were also negative. Based on symptoms, incubation period, epidemiological investigation, and laboratory results, this outbreak was most likely caused by Salmonella enteric. contamination of chicken. We recommend increased supervision and periodic examinations for food handlers. Additionally, food handlers must be trained in food safety.
Figure 1: Epi-curve chart of salmonella outbreak in specific club restaurant, Muscat, Oman, 2024
Table 1: Food‑specific attack rates and risk ratios for each food item of the foodborne outbreak in the specific club restaurant, Muscat, Oman 2024
| Food items | Ate specified food | Did not eat specified food | RR% | CI 95 | p value | |||||||
| Ill | well | total | AR % | ill | well | total | AR% | LL | UL | |||
| Meat | 36 | 4 | 40 | 90 | 32 | 56 | 88 | 36 | 2.5 | 5.1 | 48.3 | 0.000 |
| Chicken | 55 | 11 | 66 | 83.3 | 13 | 49 | 62 | 20.9 | 3.9 | 2.4 | 6.5 | 0.000 |
| Sea food | 15 | 7 | 22 | 68 | 53 | 53 | 106 | 50 | 1.3 | 0.8 | 5.6 | .12 |
| Hummus | 42 | 2 | 44 | 95.4 | 26 | 58 | 84 | 30.9 | 3.08 | 2.2 | 4.2 | 0.00 |
| Rice | 15 | 2 | 17 | 88.2 | 53 | 58 | 111 | 47.7 | 1.84 | 1.4 | 2.4 | 0.002 |
| Masala | 2 | 3 | 5 | 40 | 66 | 57 | 123 | 53.6 | 0.7 | 0.09 | 3.5 | .54 |
| Salad | 19 | 22 | 41 | 46.3 | 49 | 38 | 87 | 56.3 | 0.8 | 0.5 | 1.2 | .29 |
References:
1. Todd ECD. Foodborne Disease in the Middle East. Water, Energy & Food Sustainability in the Middle East [Internet]. 2017 Jan 1 [cited 2024 Jun 23];389. Available from: /pmc/articles/PMC7122377/
2. Majowicz SE, Musto J, Scallan E, Angulo FJ, Kirk M, O’Brien SJ, et al. The global burden of nontyphoidal Salmonella gastroenteritis. Clin Infect Dis [Internet]. 2010 Mar 15 [cited 2024 May 26];50(6):882–9. Available from: https://pubmed.ncbi.nlm.nih.gov/20158401/
3. Chai SJ, Cole D, Nisler A, Mahon BE. Poultry: the most common food in outbreaks with known pathogens, United States, 1998-2012. Epidemiol Infect [Internet]. 2017 Jan 1 [cited 2024 May 26];145(2):316–25. Available from: https://pubmed.ncbi.nlm.nih.gov/27780481/