Investigating the origin of imported dengue cases and characteristics of dengue epidemics: the role of inter-regional flows in the spread of epidemics in a city of regional influence under tropical climate

Introduction: In the state of São Paulo, Brazil, studies have identified a high incidence in the coastal cities of the state, particularly in Santos, the largest port. However few studies have looked at the contribution of... [ view full abstract ]

Introduction: In the state of São Paulo, Brazil, studies have identified a high incidence in the coastal cities of the state, particularly in Santos, the largest port. However few studies have looked at the contribution of flows in the spread of epidemics.

Objectives: To investigate imported dengue cases in epidemics and to describe the main epidemiological characteristics in Araraquara, in the state of São Paulo.

Methods: Use of all reported cases of dengue from the Information System for Notifiable Diseases (SINAN) from 1998 to 2013. Dengue incidence was calculated for each year and a Geographic Information System was used to map the sites of infection of imported cases.

Results: There was increase of dengue incidence and annual variation in the epidemiological pattern of the disease. Imported cases of dengue occurred both in epidemic and inter-epidemic years However there were higher numbers of imported cases in the inter-epidemic periods and most were imported from other municipalities of the State of São Paulo.

Conclusion: Results demonstrated the relevance of imported cases of dengue in different years in the spread of epidemics. Also pointed important changes in the epidemiology of dengue regarding age, gender and site of infection. The finding reinforces the need for actions to combat dengue also in schools, in the workplace and at points of arrival and departure of people in the city, such as transportation terminals, sugar cane and orange juice industries that export their products through the port, bus terminals and bus locations.
It also highlights the need for targeted vector control programs and surveillance of travelers at ports, airports, bus station, train station, truck transportation and logistics enterprises as well as regularly affected local areas.