Aim/background: Large outbreaks of foodborne diseases are always focused by the general public who expect experts to rapidly explain both the causes of the disease and its growth. This article presents the results of the investigation of an outbreak of foodborne disease that has attracted much of the electronic and written media attention.
Methods: The data on food items consumed by intoxicated and healthy soldiers were obtained by the adapted questionnaire during a field investigation performed on November 3-4, 2005. On the same occasion other relevant data were also collected. For microbiological investigations stool samples from the ill persons were collected, as well as food specimen and swabs from the working surfaces and utensils in the kichen where the food had been prepared.
Results: In the outbreak of foodborne disease, which started on November 2, 2005, and terminated on the next day, 103 ill soldiers were registered in 7 units scattered over 4 locations in the garrison of Nis. The attack rate varied in the affected units from 33 to 338 per thousand, with the mean value of 109.7 per thousand. The clinical course of the disease was predominantly light including vomiting, diarrhea and fever as the most frequent signs of illness. All the affected soldiers were hospitalized, treated with symptomatic therapy, and discharged fully recovered. By comparing dishes that had been consumed by the ill and the healthy persons before the beginning of the outbreak, the greatest statistical significance (p < 0.0001), and the only significant relative risk (RR = 3.43) were related to the consumption of the coleslaw served for lunch on November 1, 2005. In addition, two control groups with the total of 151 persons who had not consumed the coleslaws were identified no one of them was affected. An microbiological investigation did not reveal any bacterial enteropathogens.
Conclusion: In the described foodborne disease outbreak a causative agent was not identified although coleslaw was the way of transmission probably secondarily contaminated by the improper hygiene practice during its processing.