The role of inter-regional flows in the spread of epidemics in a city of regional influence with a tropical climate.

The aim of this research was to investigate the origin of imported cases of dengue in the city of Araraquara, Brazil and to describe the disease's main epidemiological characteristics. The study encompassed all confirmed cases of dengue recorded in the Information System for Notifiable Diseases (SINAN) [Sistema de Informacao de Agravos de Notificacao] from 1998 to 2013. Cases whose origin of infection was likely located outside Araraquara were considered imported. The epidemiological study entailed a descriptive analysis of the data, regarding the distribution of cases by sex, age, and classification of imported and autochthonous cases. A geographic information system was used to map flows and estimate distances. There were 6,913 confirmed cases, 419 of which were imported. In most cases, the origin of infection was located in the state of Sao Paulo as well as other Brazilian regions. The results indicate the relevance of imported cases and differences in the epidemiological profile with respect to age and sex. Conclusions indicate the need to increase epidemiological and environmental health surveillance at ports, airports, truck stops, and bus and train terminals.