Objective: To identify the source of infection and risk factors and to provide control measures regarding an outbreak of gastroenteritis involving 30 villagers. Who attended the same wedding party held on March 5(th), 2012, a survey was carried out.
Methods: Case was defined as having onset of vomiting, nausea, stomachache or diarrhea among the attendees of a wedding party. We randomly selected and interviewed 140 from 470 attendees on their symptoms and food exposures at the wedding. We compared food-specific attack rates (AR) for gastroenteritis in a retrospective cohort study. The leftover foods were tested for Salmonella, Shigella, and Staphylococcus aureus. The leftover Boletus mushrooms were examined and species determined by the Kunming Institute of Botany, Chinese Academy of Sciences.
Results: Of the 140 attendees 61% (85) developed gastroenteritis. Case-attendees had vomiting (94%), nausea (89%), stomachache (53%), and diarrhea (51%). The AR among attendees who ate Boletus mushroom was 69% (81/118), compared to 18% (4/22) of those who did not (RR = 3.8, 95%CI: 1.5 - 9.2). When comparing the ARs between the attendees on consumption of other foods, data did not show statistically significant differences. Among the 7 species of Boletus identified from the leftover mushrooms, 3 (B. venenatus, B. sinicus and B. magnificus) were toxic. Store keepers bought dried or fresh mushrooms from local villagers who had picked up them from the mountains. Salmonella, Shigella, and Staphylococcus aureus tests on those leftover food showed negative results.
Conclusion: Poisonous Boletus mushroom contributed to this outbreak. We recommended that education should be targeted on mushroom-pickers regarding how to recognize the poisonous mushrooms. Regulations and laws should also be developed to facilitate the necessary process.