Seasonality of Sonne dysentery among organized and unorganized groups of children in years with different morbidity levels

: Differences in the monthly distribution of morbidity in Sonne dysentery among children of preschool age in children's institutions and among those not attending such institutions have been revealed. In years characterized by a high morbidity level, the epidemic process develops simultaneously among all children with some prevalence in its activity being observed from January to August among children not attending children's institutions and from September to December among institutionalized children. In years characterized by a low morbidity level, the rise of morbidity among children aged up to 3 years, both seasonal and not connected with the season (in January), is determined by the rise of morbidity among those children who attend children's institutions, while among noninstitutionalized children aged 4-6 years the seasonal rise of morbidity begins and becomes manifest earlier.