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Open Access Research article

Hydroclimatological variability and dengue transmission in Dhaka, Bangladesh: a time-series study

Masahiro Hashizume1*, Ashraf M Dewan23, Toshihiko Sunahara1, M Ziaur Rahman4 and Taro Yamamoto1

Author Affiliations

1 Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan

2 Department of Geography and Environment, University of Dhaka, Ramna 1000, Dhaka, Bangladesh

3 Department of Spatial Sciences, Curtin University of Technology, Kent Street, Bentley 6102, Perth, Australia

4 Department of Sociology, University of Dhaka, Ramna 1000, Dhaka, Bangladesh

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BMC Infectious Diseases 2012, 12:98  doi:10.1186/1471-2334-12-98

Published: 24 April 2012

Abstract

Background

While floods can potentially increase the transmission of dengue, only few studies have reported the association of dengue epidemics with flooding. We estimated the effects of river levels and rainfall on the hospital admissions for dengue fever at 11 major hospitals in Dhaka, Bangladesh.

Methods

We examined time-series of the number of hospital admissions of dengue fever in relation to river levels from 2005 to 2009 using generalized linear Poisson regression models adjusting for seasonal, between-year variation, public holidays and temperature.

Results

There was strong evidence for an increase in dengue fever at high river levels. Hospitalisations increased by 6.9% (95% CI: 3.2, 10.7) for each 0.1 metre increase above a threshold (3.9 metres) for the average river level over lags of 0–5 weeks. Conversely, the number of hospitalisations increased by 29.6% (95% CI: 19.8, 40.2) for a 0.1 metre decrease below the same threshold of the average river level over lags of 0–19 weeks.

Conclusions

Our findings provide evidence that factors associated with both high and low river levels increase the hospitalisations of dengue fever cases in Dhaka.

Keywords:
Bangladesh; Climate; Dengue; River level; Time-series