[Epidemiological characteristics on temporal-spatial distribution of varicella in Guangxi Zhuang Autonomous Region, 2014-2016].

Objective: To analyze the epidemiological characteristics of temporal-spatial distribution on varicella in Guangxi Zhuang Autonomous Region (Guangxi) during 2014 to 2016. Methods: Incidence data on varicella was collected from the National Notifiable Infectious Disease Reporting Information System (NNIDRIS) of the Center for Disease Control and Prevention (CDC) while geographic information data was from the national CDC. ArcGIS 10.2 software was used to analyze global and local spatial auto correlation on spatial clusters. SaTScan v9.1.1 was used to conduct temporal-spatial scan for exploring the areas of temporal-spatial clusters. Results: The overall incidence rates of varicella during 2014 to 2016 were 32.48/100 000, 43.56/100 000 and 61.56/100 000 respectively. Incidence of varicella showed a positive spatial auto correlation at the county level (the value of Moran's I was between 0.24 to 0.35, P <0.01), with consistent high morbidity. High-high cluster areas were seen and mainly concentrated in the north-western areas of Guangxi. Result from the temporal-spatial scan showed that temporal cluster of varicella occurred mainly between October and next January while the type Ⅰ cluster area was mainly distributed in all of the counties in Hechi city and most counties of Baise city, with most counties being covered in the north-western areas of Guangxi, during 2014-2016. When comparing to data from the last two years, two type Ⅱ cluster areas with larger scales were formed in the north-eastern area of Guanyang county and Haicheng county of southern area in Guangxi, in 2016. Conclusions: Incidence on Varicella seemed on the rise, and the distribution of cases showed clustered features, both on time and space. Strategies regarding control and prevention on Varicella should focus on high-high clustered areas, namely north-western areas of the province, including surrounding areas during the high onset season.