An Ecologic Study of Poliomyelitis in Connecticut, 1931-1941 *

This is a study on the ecology of poliomyelitis in the State of Connecticut. It has been undertaken to see what the experience with this disease has been in this state, with particular reference to certain local epidemiologic features, such as (a) its geographic, seasonal, and age distribution, and (b) a comparison of the findings with those of typhoid fever. In particular, the effort has been made to compare the rural prevalence of poliomyelitis with its urban presence in this state. This has been done because some observers in the past, Wickman"2 among the first of them, noted that epidemics of poliomyelitis were likely to be more severe in sparsely settled communities. Lavender, Freeman, and Frost7 stated that "the proportionately greater rural prevalence has in fact been so constant as to be unmistakably due not to mere chance but to some fundamental law." Others',3 have pointed out that the disease is more widely prevalent, and more severe, during epidemic times in suburbs or outskirts of cities than in the densely populated city precincts. Muller8 and Jonsson,4 on the other hand, could not detect any significant difference in the attack rates in the cities and in the surrounding country districts which they studied. As to endemic poliomyelitis in rural and urban areas, only a few studies are on record, which suggest that the endemic disease attacks rural areas more severely than urban ones, although Godfrey2 studied the distribution of cases and deaths of poliomyelitis (19151924) and observed that communities with less than 5,000 population had high attack rates compared with more densely populated areas. We have also been concerned in this report with the question as to whether there are any particular areas in which the disease is more common than elsewhere, being guided somewhat by the fact