The Spatiotemporal Expansion of Human Rabies and Its Probable Explanation in Mainland China, 2004-2013

Hong-Wu Yao, Yang Yang, Kun Liu, Xin-Lou Li, Shu-Qing Zuo, Ruo-Xi Sun, Li-Qun Fang , Wu-Chun Cao 

PLOS Neglected Tropical Diseases

February 18, 2015

Background

Human rabies is a significant public health concern in mainland China. However, the neglect of rabies expansion and scarce analyses of the dynamics have made the spatiotemporal spread pattern of human rabies and its determinants being poorly understood.

Methods

We collected geographic locations and timeline of reported human rabies cases, rabies sequences and socioeconomic variables for the years 2004-2013, and integrated multidisciplinary approaches, including epidemiological characterization, hotspots identification, risk factors analysis and phylogeographic inference, to explore the spread pattern of human rabies in mainland China during the last decade.

Results

The results show that human rabies distribution and hotspots were expanding from southeastern regions to north or west regions, which could be associated with the evolution of the virus, especially the clade I-G. A Panel Poisson Regression analysis reveals that human rabies incidences had significant correlation with the education level, GDP per capita, temperature at one-month lag and canine rabies outbreak at two-month lag.

Conclusions

The reduction in the overall human rabies incidence was accompanied by a westward and northward expansion of the circulating region in mainland China. Higher risk of human rabies was associated with lower level of education and economic status. New clades of rabies, especial Clade I-G, played an important role in recent spread. Our findings provide valuable information for rabies control and prevention in the future.

Author Summary

Although the number of human rabies cases has slightly decreased since 2008 in mainland China, the rabies seemed to be gradually expanding to the low-incidence or non-epidemic areas. The neglect of rabies expansion and scarce analyses of the dynamics have made the spatiotemporal spread pattern of human rabies and its determinants poorly understood. Here, we integrate multidisciplinary approaches to explore and describe the spread pattern and evolution dynamic of human rabies in mainland China during the last decade. The results indicated that the reduction in the overall human rabies incidence was accompanied by a westward and northward expansion of the circulating region, which could be associated with the evolution of the virus, especially the clade I-G. And the education level, GDP per capita, temperature at one-month lag and canine rabies outbreak at two-month lag were firstly found to be significant correlation human rabies incidences according to the Panel Poisson Regression analysis. Our findings give a relatively complete picture about the human rabies spatiotemporal dynamics and spread pattern, thus provide new insights on risk factors and control strategies for the disease spread.