On Wednesday 8th of March 2017, an outbreak of gastrointestinal illness was reported in "Othman bin Affan school" where 28 students were affected and evacuated by the Red Crescent to hospitals in Arar. The data (number of students in school, number of meals and number of affected students) was provided by the Manager of Othman Bin Affan School, which we visited. The nutrition in this school, is usually managed by school administration and has its own canteen. The school health department is responsible for issuing and monitoring the regulations related to the operation of this canteen. The Health Department has a list of requirements for each food item to be sold in canteen. On 9th March 2017, I received a call from FETP about the outbreak and a team consist of Dr Mohd Althebyani and I to go to Arar to investigate the outbreak.
Methodology
Study design: case control study Case definition: Any student got gastric symptoms after eating from school canteen on Wednesday March 8,2017 Exposure: food items from school canteen (pies, nectar, popcorn) Study population: school students Risk Group: all students who ate that day from canteen that day Sample size: all cases attend school on Wednesday March 15 ,2017 and same number control Data collection: 1. questionnaire 2. field visit
Results
Attack rate: 28 \100 Response rate 23\28 5 students absent Epi curve: first case 10:45, peak time 11:00 am As part of the investigation was a visit to the bakery concerned, the following was found: 1. There is no proper storage. The raw material are mixed with hazardous material (gasoline) 2. The shop structure is not in a good condition 3. The room where the food is being prepared is not organized and is not a safe place to work. 4. The leftover bread is mixed with freshly baked ones 5. The staff were not hygienic. They did not have proper uniforms, and did not use gloves when preparing the bread 6. The bakery supplies to 10 different school 7. The bakery and staff did not have a license to operate.
Conclusion
As eleven schools taken food from same source, only one school announced food poisoning outbreak and the attack rate was 28%. the Epi curve shows that the first was at 10:45 am and the peak was at 11:00 am which indicate that the incubation period was short for about 30 minutes and common symptoms was upper GI symptoms (abdominal pain 95% and 65% vomiting) while only 40% of cases complained of diarrhea so this result can put Staphylococcus aureus as a deferential diagnosis. Chemical contamination can be one of the differential diagnosis since food ingredients were stored with hazardous materials . The outbreak and recovery were rapid as all students recovered and discharged from A&E from same day and all lab result were negative which put mass sociogenic illness as one of most propable diffrential diagnosis. whereas the nectar and popcorn are packed product with mass production and the pie locally made in bakery with low quality as mentioned above and about 50% of cases notes changes in pie taste, smell and freshness. unfortunately