EVALUATION OF AN INTERVENTION PROGRAM FOR THE CONTROL OF AN OUTBREAK OF SHIGELLOSIS AMONG INSTITUTIONALIZED PERSONS

After control measures were initiated to stop an outbreak of shigellos is in an institution for the developmentally disabled, there was a sha rp decline in the number of cases of Shigella sonnei infection. Among ill residents, those treated with antibiotics had shorter mean duratio n of diarrhea (2.4 vs. 4.5 days, P < .01) and were less likely to have stool cultures positive for shigellae 2-4 weeks after onset of diarrh ea (0/25 vs. 5/19; relative risk [RR] = undefined; P = .02). The attac k rate was higher in villages where segregation of ill residents was n ot practiced (46/73 vs. 53/155; RR = 1.8; 95% confidence limits [CL], 1.4, 2.4). In individual housing units where ill residents were not se gregated (preintervention), a correlation was found between mean durat ion of diarrhea and unit-attack rates (r = .88; 95% CL, 0.29, 0.99). A study of all 305 residents 10 weeks after the intervention began reve aled no positive stool cultures.