Space-time analysis of human brucellosis considering environmental factors in Iran

Objective: To investigate the associations between the brucellosis and four climatic factors including temperature, precipitation, wind speed and greenness for better understanding the epidemiology of the disease in Iran during April 2009 to March 2012. Methods: A cross-sectional survey was performed on 39 359 recorded cases during the study period. Pearson's correlation coefficient was used to investigate statistically meaningful temporal and spatial relevance between the disease and parameters. Besides, multiple linear regression was applied to estimate the best combination of the variables for predicting brucellosis incidence. Results: Pearson's analysis revealed that there are positive temporal correlations between incidence and temperature, wind speed and greenness. Besides, a strong negative temporal association was observed with precipitation. Although a remarkable negative spatial association was observed between aggregated incidence rates and vegetation cover of corresponding counties in winter, this correlation was strongly positive for spring and summer.