Spatiotemporal Analysis of National Scrub TYphus Occurrence: 2001-2010

Abstract

Orientia tsutsugamushi is a causative agent of scrub typhus, a zoonotic disease, distinguished by symptoms of sudden high fever and macular rash. The number of incidences had exploded in Korea over the past decade. This study was performed to investigate the spatial and temporal factors associated with scrub typhus occurrences in Korea. The study population of the study is all the scrub typhus cases reported within Korea from 2001 to 2010. Among the scrub typhus cases, more cases were reported among females, older age groups, and agricultural and fishery occupational group. The study not only observed associations with scrub typhus incidence counts, but also with crude incidence rates and age-gender standardized incidence rates. Morans I and LISA were observed for each year to understand spatial autocorrelations. The proportions of dry-field use, paddy-field use, and orchard use were considered as areal characteristics, and were analyzed through spearman rank correlation test and negative binomial regression analysis. There were significant clustering of scrub typhus occurrences with positive linear trend and although all types of land use had significant results, highest correlation coefficient was observed between scrub typhus occurrences and the proportions of paddy field use in PHC level regions. The results from negative binomial regression analysis also support with significant level of results explaining the effect size of paddy field proportions.