Spread of tuberculosis from house to house.

This investigation originates from an observation made in 1948 that many tuberculous patients in Northampton lived next door to one another. It was decided to find out whether the pattern of the disease in this town suggested that persons living next door to tuberculous subjects are unduly prone to contract the disease. The first step was to discover the position of houses from which cases of tuberculosis had been notified from 1921 to 1948. We next studied other possible influences on the pattern of the disease, to see whether, allowing for these, the position of the affected houses suggested a random distribution of cases, or revealed the transmission of disease between neighbours. Finally, to decide whether the setting of the investigation was exceptional, the population and social conditions of Northampton were examined, by comparing the borough as a whole with other towns, and by comparing different districts within the borough.