For some time the question of geographic variation in the incidence of mastoiditis has been of interest and an attempt at an explanation has thus been undertaken. There is much literature regarding climate in general terms. The weather and season function together as the most important environmental factor from the time of birth to the time of death of an individual. Acute infections of the mastoid reach their peak in the spring following the cold weather, not in the summer, and do not again begin to rise until the fall, when changes, often sudden, are seen.
Throughout the United States there is every variety of climate and of weather conditions. Too, one sees a great variety of peoples from every nation scattered throughout the country. These people and their respective living conditions as well as their racial immunity make them susceptible or resistant to different disease conditions.
An organism virulent
LYNCH MG. GEOGRAPHIC VIRULENCE OF MASTOIDITIS. JAMA. 1940;115(10):826-828. doi:10.1001/jama.1940.02810360014004