Virus infections

Spatial analysis of notified dengue fever infections

W. HU^a1 c1, A. CLEMENTS^a1a2, G. WILLIAMS^a1 and S. TONG^a3

^a1 School of Population Health, The University of Queensland, Australia

^a2 Australian Centre for International and Tropical Health, Queensland Institute of Medical Research, Australia

^a3 School of Public Health, Queensland University of Technology, Australia

SUMMARY

This study aimed to investigate the spatial clustering and dynamic dispersion of dengue incidence in Queensland, Australia. We used Moran's I statistic to assess the spatial autocorrelation of reported dengue cases. Spatial empirical Bayes smoothing estimates were used to display the spatial distribution of dengue in postal areas throughout Queensland. Local indicators of spatial association (LISA) maps and logistic regression models were used to identify spatial clusters and examine the spatio-temporal patterns of the spread of dengue. The results indicate that the spatial distribution of dengue was clustered during each of the three periods of 1993–1996, 1997–2000 and 2001–2004. The high-incidence clusters of dengue were primarily concentrated in the north of Queensland and low-incidence clusters occurred in the south-east of Queensland. The study concludes that the geographical range of notified dengue cases has significantly expanded in Queensland over recent years.

(Accepted March 12 2010)

(Online publication April 15 2010)

Key Words:

• Dengue;
• LISA;
• Moran's I;
• spatial analysis;
• spatial empirical Bayes smoothing

Correspondence:

^c1 Author for correspondence: Dr W. Hu, School of Population Health, The University of Queensland, Herston Road, Herston, Qld 4006, Australia. (Email: w.hu@sph.uq.edu.au)