A FOODBORNE OUTBREAK OF CAMPYLOBACTER-JEJUNI (O-33) INFECTION ASSOCIATED WITH TUNA SALAD - A RARE STRAIN IN AN UNUSUAL VEHICLE

We report a foodborne outbreak of Campylobacter jejuni infection in a summer camp. Outbreak-related cases occurred in 79 persons including 3 secondary cases in campers. Campylobacter jejuni was isolated from st ool specimens from 16 of 21 patients who submitted a sample; 13 viable isolates were serotyped and all were serotype O:33 (somatic O scheme) or HL:18 (heat-labile scheme), and biotype III (Lior scheme). This se rotype is widely distributed geographically but rarely isolated from h umans, Samples of water from the wells supplying the camp were negativ e for faecal coliforms, and raw milk had not been served in the camp. A matched (1:1)case-control study identified tuna salad served for lun ch on 19 July as the likely food item associated with illness (matched odds ratio = 22; 95 % confidence intervals (CI) = 3.6-908). Swimming in the camp pool and other recreational water use in area lakes by the campers were not statistically associated with illness. The precise m echanism of introduction of the organism into the tuna salad remains u nknown; contamination most likely occurred through cross-contamination with another food product, the hands of a food handler, or a work sur face. Several deficiencies in the operation of the camp kitchen were i dentified. In Wisconsin, kitchens of such camps are subject to differe nt inspection rules than restaurants. Camp staff, administrators, coun selors, food managers, and infirmary staff, should fulfil important ro les in their respective areas to prevent future outbreaks.