The Allegheny County Health Department (ACHD) is currently investigating an outbreak of shigellosis (Shigella infection) linked to daycare facilities in Allegheny County. An unusually high number of cases have been reported to ACHD since October of 2014. Cases range in age from 6 months to 68 years with a median age of 5 years. About half of the cases are associated with day care facilities in Allegheny County. Increases in shigellosis have also been observed in surrounding counties in southwestern Pennsylvania.