Camp Gastro: Norovirus Outbreak
It was a bright sunny day, and the overnight camp was in session for 48 hours when a camper came to the infirmary with a complaint of nausea. He did not have fever, vomiting, or diarrhea. He described a “queasy” feeling in his stomach. The camper was told to rest, drink fluids, and return to the infirmary if he developed other symptoms or felt worse. He returned about one hour later looking pale and then vomited multiple times in the infirmary. Within 24 hours, eight more campers — most from the same bunk as the initial camper — arrived at the infirmary with nausea, vomiting, and malaise.
The differential between an infectious agent versus food poisoning as an etiology was considered. We were not able to identify a common food that all of the symptomatic campers had eaten. Over the next 24–48 hours about 30 campers became acutely ill with vomiting and, occasionally, diarrhea. Some of the campers had fever. The sick campers were isolated from asymptomatic campers and strict hand-washing and cleansing protocols were established. Over the next four days, between five to ten campers per day became ill and developed nausea, vomiting and, less often, diarrhea. Strict hand-washing policies were continued, bunks were cleaned, and food-service changes were made. These changes included the elimination of salad bars and the use of gloves by counselors who served food. Food-sharing was also prohibited.
Acute symptoms of vomiting and nausea lasted about 12 hours, with malaise often lasting for 24–48 hours. About 70 campers, counselors, and staff were infected in total. The camp houses about 400 campers and 200 staff and counselors. Two medical staff, who had spent many hours caring for sick patients, also became ill. The attack rate was about 12%.