On Thursday 26 July 2006 at about 2am several cases of gastroenteritis arrived to the emergency department of King Faisal Hospital in Taif city complaining of diarrhea, abdominal pain and fever. It was found that all of them belonged to one extended family. So an investigation initiated to identify the food item responsible for the outbreak and determine the cause of infection.
Methodology
A retrospective cohort study was conducted. A person to person interview was conducted with all exposed family members who ate dinner at home on July 26th 2006 inquiring about food consumed, if they developed any symptoms, and if they were then hospitalized. Any one from the 4 families who developed any of the following symptoms: diarrhea, nausea, vomiting, abdominal pain, or fever, within 3 days since July 26th 2006 was considered a case.
Results
A total of 64 individuals were interviewed. Out of them 39 developed gastroenteritis, most commonly manifested by diarrhea ( 97.4%),fever (79.5%),abdominal pain(71.8%).Majority interviewed persons were Saudis (59) individual and 5 non Saudi who were house maids, 21 were males(32.8%) 43 were females(67.2%).The median incubation period was 2 hours and the epidemic curve suggested a common point source outbreak. Out of 7 food items available at dinner that night ,cow milk was the only food item significantly associated with illness ,with RR=5.45,(95% CI=1.9039-15.6269), samples taken from cow milk were positive for E-coli.
Conclusion
E-coli was considered the causative agent of this foodborne outbreak. Homemade laban from raw milk was the incriminated food item, lack of pasteurization of milk with unhygienic handling, poor transportation and storage facilities were the main factors leading to this outbreak.