Patterns of Bacillary Dysentery in China, 2005-2010.

Han Zhang,Peng Gong,Xiaofeng Wang,Yali Si

doi:10.3390/ijerph13020164

Abstract

Although the incidence of bacillary dysentery in China has been declining progressively, a considerable disease burden still exists. Few studies have analyzed bacillary dysentery across China and knowledge gaps still exist in the aspects of geographic distribution and ecological drivers, seasonality and its association with meteorological factors, urban-rural disparity, prevalence and distribution of Shigella species. Here, we performed nationwide analyses to fill the above gaps. Geographically, we found that incidence increased along an east-west gradient which was inversely related to the economic conditions of China. Two large endemically high-risk regions in western China and their ecological drivers were identified for the first time. We characterized seasonality of bacillary dysentery incidence and assessed its association with meteorological factors, and saw that it exhibits north-south differences in peak duration, relative amplitude and key meteorological factors. Urban and rural incidences among China’s cities were compared, and disparity associated with urbanization level was invariant in most cities. Balanced decrease of urban and rural incidence was observed for all provinces except Hunan. S. flexneri and S. sonnei were identified as major causative species. Increasing prevalence of S. sonnei and geographic distribution of Shigella species were associated with economic status. Findings and inferences from this study draw broader pictures of bacillary dysentery in mainland China and could provide useful information for better interventions and public health planning.

Highlights

Bacillary dysentery, caused by Shigella bacteria, is of considerable global public health concern, especially in developing countries and low income regions [1,2]
From 2005 to 2010, provincial average incidence generally increased along an east-west gradient and was inversely associated with economy (Spearman correlation coefficient r = ́0.471, p < 0.01), as provinces with higher incidence were generally concentrated in less developed western China, while incidence rates were lower in more developed eastern and central provinces (Global Moran’s Index: 0.233, Z-Score: 2.936, p < 0.01) (Figure 1 and Figure S2)
The study has demonstrated that bacillary dysentery incidence increased along an east-west gradient across China

Summary

Introduction

Bacillary dysentery, caused by Shigella bacteria, is of considerable global public health concern, especially in developing countries and low income regions [1,2]. Facilitated by the low dose of organisms required for infection [3], Shigella can be transmitted by the fecal-oral route via contaminated water, food, articles for daily use, and person-to-person contact. Infrastructures and sanitation, and unhygienic behaviors have been associated with dysentery [1,2,4]. China has made rapid improvements in water supply and sanitation [4], and incidence of bacillary dysentery has declined markedly, but a considerable disease burden still exists and is unevenly distributed across China [5,6]. Res. Public Health 2016, 13, 164; doi:10.3390/ijerph13020164 www.mdpi.com/journal/ijerph

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Discussion

Conclusion