Spatiotemporal Variation and Hotspot Detection of the Avian Influenza A(H7N9) Virus in China, 2013⁻2017.

Zeng Li,Gang Lin,Dong Jiang,Jingying Fu

doi:10.3390/ijerph16040648

Abstract

This study aims to describe the spatial and temporal characteristics of human infections with H7N9 virus in China using data from 19 February 2013 to 30 September 2017 extracted from Centre for Health Protection of the Department of Health (CHP) and electronic databases managed by China’s Center for Disease Control (CDC) and provincial CDCs synthetically using the Geographic Information System (GIS) software ArcMap™ 10.2 and SaTScan. Based on the multiple analyses of the A(H7N9) epidemics, there was a strong seasonal pattern in A(H7N9) virus infection, with high activity in the first quarter of the year, especially in January, February, and April, and a gradual dying out in the third quarter. Spatial distribution analysis indicated that Eastern China contained the most severely affected areas, such as Zhejiang Province, and the distribution shifted from coastline areas to more inland areas over time. In addition, the cases exhibited local spatial aggregation, with high-risk areas most found in the southeast coastal regions of China. Shanghai, Jiangsu, Zhejiang, and Guangdong were the high-risk epidemic areas, which should arouse the attention of local governments. A strong cluster from 9 April 2017 to 24 June 2017 was also identified in Northern China, and there were many secondary clusters in Eastern and Southern China, especially in Zhejiang, Fujian, Jiangsu, and Guangdong Provinces. Our results suggested that the spatial-temporal clustering of H7N9 in China is fundamentally different, and is expected to contribute to accumulating knowledge on the changing temporal patterns and spatial dissemination during the fifth epidemic and provide data to enable adequate preparation against the next epidemic.

Highlights

The first human infection with avian influenza A(H7N9) was observed in Shanghai in March2013 [1]
This study aims to conduct multiple analyses of the H7N9 epidemics to increase understanding of the current features of the epidemiological distribution of the virus and to explore its temporal and geographical patterns, especially its spatial-temporal clustering
The fifth epidemic started earlier in the year and affected more individuals and more districts than did the previous four epidemics based on analyses of the timeline and geographical distribution

Summary

Introduction

The first human infection with avian influenza A(H7N9) was observed in Shanghai in March2013 [1]. The first human infection with avian influenza A(H7N9) was observed in Shanghai in March. It posed a great pandemic threat to humans; previously the A(H7N9) virus had been detected only in birds. Due to its high pathogenicity and prevalence, the novel H7N9 virus was defined as “an unknown threat” by WHO (World Health Organization) and has attracted much attention [2]. During the past five years, the avian influenza virus has evolved and acquired mutations in the processes of continuous transmitted infections. Several experiments in 2016 revealed that some avian. Res. Public Health 2019, 16, 648; doi:10.3390/ijerph16040648 www.mdpi.com/journal/ijerph

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