A Spatial Variant of the Basic Reproduction Number for the New Orleans Yellow Fever Epidemic of 1878

Abstract

A spatial variant of the basic reproduction number (R 0), here defined as the number of subsequent deaths attributed to an initial mortality, can be used to identify geographic variation within an epidemic. A spatial R 0 was calculated at the neighborhood level, here defined by a 50-m buffer surrounding an index case, for mortality data from the 1878 yellow fever epidemic of New Orleans. The highest number of secondary mortalities linked to a neighborhood index case was twelve, with a further eighty-seven extrapolated morbidity cases. Results also highlight the importance of multideath residences and cultural contacts in neighborhood-level disease spread.