BACKGROUND: Since 2015, U.S. outbreaks of Salmonella serotype I 4,[5],12:i:- with pulsed-field gel electrophoresis pattern JPXX01.1314 have been associated with pork consumption. During July 2016, the San Bernardino County and California Departments of Public Health detected an outbreak of this strain with two illness waves at a kosher summer camp, making pork an unlikely source. We investigated to identify infection source and prevent further illness.
METHODS: Case-patients were defined as campers with diarrhea onset or outbreak strain infection with stool collection during June 27–July 21, 2016. A case-control study compared food and environmental exposures of case-patients aged 12–14 years with onsets during the first illness wave with non-ill campers (control subjects) in the same aged bunks. Ten of 15 case-patients and 10 of 33 control subjects were interviewed for the study. An environmental assessment of the camp and off-site campground used for overnight trips July 4–8 was performed.
RESULTS: Twenty-seven of 165 campers became ill during two waves, July 1–4 (n = 15) and July 6–12 (n = 12). No statistically significant exposures were identified, although campers reported cooking raw beef and chicken and soap being absent during overnight trips. The pump handle of a well, the only campground water source, tested positive for the outbreak strain. Of 19 food samples collected, nine had lactose-fermenting bacterial growth, indicating fecal contamination; none grew Salmonella.
CONCLUSIONS: No vehicle was identified, but consumption of contaminated food and person-to-person transmission might have contributed to illness. The well-pump handle and food testing results highlight the need for food preparation and hygiene education. On July 13–14, the camp was sanitized; no additional cases were reported.