REACTIVE ARTHRITIS FOLLOWING AN OUTBREAK OF SALMONELLA INFECTION IN FINLAND

The incidence and clinical features of reactive arthritis (ReA) follow ing an outbreak of enteritis caused by Salmonella enterica ssp, enteri ca serovar 4,5,12:b:-were studied in the autumn of 1992. The outbreak occurred in several municipalities and originated from sprouted mung b eans. A questionnaire on extra-enteric manifestations such as joint an d eye symptoms was mailed 2 to 5 months after the outbreak to all bact eriologically proven cases. Two hundred and forty-six of the 272 (90%) subjects responded to the questionnaire; 224 (91%) reported having ha d enterocolitis, 22 (9%) were asymptomatic. Sixteen subjects fulfilled the criteria for ReA, and one had irities only. Thus, the incidence o f ReA/iritis after S. enterica was 6.9%. Only four of the 155 (3%) sub jects aged less than 16 yr developed ReA, as compared with 12 of the 9 1 (13%) older patients (P<0.001). The only patient with iritis was als o more than 16 yr old. The joint symptoms were oligoarticular in 10 (6 3%), monoarticular in five (31%) and polyarticular in one (6%). The mo st frequently affected joints were the wrists, knees and ankles. Joint s of upper extremities only were affected in three (19%), of the lower extremities only in six (37%) and of both in seven (44%) subjects. In the majority of the patients ReA was mild. The joint symptoms persist ed for less than 1 month in six, 2 to 6 months in five and more than 6 months in five. Thirteen subjects with ReA/iritis were tissue-typed f or HLA; four (33%) had HLA-B27. Three HLA-B27-negative subjects had an tigens of HLB-B27 crossreacting groups; two had B40 and one B7. The du ration or severity of arthritis were similar in the HLA-B27 positive a nd negative patients.