佛山市2013—2017年人感染H7N9禽流感疫情时空流行特征分析

Spatial-temporal epidemiological analysis of human infections with avian influenza A (H7N9) virus in Foshan,2013-2017

目的对2013年12月至2017年9月佛山市人感染H7N9禽流感疫情空间、时空流行特征进行分析。方法对2013年12月至2017年9月佛山市人感染H7N9禽流感疫情数据使用Geoda v1.12进行全局、局部自相关分析,使用SaTScan v9.4.3进行时空扫描分析。结果在实施活禽限制销售前,佛山全局Moran’s I结果显示2013年冬季至2015年春季的流行季佛山市人感染H7N9禽流疫情分布随机,局部Moran’s I结果显示2013年冬季至2014年春季,南海区大沥镇为"高-高"聚集区(局部Moran's I为1.24,P<0.05)。时空聚集性分析显示2014年1月南海区大沥镇、禅城区祖庙街道疫情呈聚集性(RR=50.35, P<0.01)。佛山市在全市各区中心城区实施活禽限制销售后,空间流行特征发生变化,全局Moran’s I显示2016年冬季至2017年春季佛山市人感染H7N9禽流感疫情呈聚集分布,局部Moran’s I显示南海区九江镇为"高-高"聚集区(局部Moran's I为5.58,P<0.01),时空聚集性分析显示2016年12月至2017年1月九江镇、西樵镇为疫情聚集区(RR=25.10,P<0.05)。结论佛山市人感染H7N9禽流感疫情存在明显的空间聚集性以及时空聚集性,实施活禽销售限制前后疫情流行特征有所差别,实施前疫情总体呈随机分布,但人口密集地区有聚集倾向;实施活禽限制销售后,疫情聚集区以未实施活禽销售限制地区为主。

Objective To describe and analyze the spatial and temporal-spatial epidemiological characteristics of human infection with avian influenza A(H7N9)virus in Foshan City from 2013 to 2017.Methods Software Geoda v1.12 was used to analyze the global and local auto-correlation(GISA and LISA)of human infection with H7N9 avian influenza from December 2013 to September 2017 in Foshan City. SaTScan v9.4.3 was used for spatial-temporal scanning analysis. Results Before the restricted sale policy for live poultry was implemented,the GISA Moran’s I showed that the cases of human infection with avian influenza A(H7N9)occurred randomly during the 2013-2015 epidemic period. LISA Moran’s I showed that Dali Town in Nanhai District was a"High-high"clustering area(LISA Moran’s I =1.24,P<0.05). Spatial-temporal scanning statistics further showed that the epidemic peak of human infection with H7N9 avian influenza was observed in January 2014 in Dali Town,Nanhai District and Zumiao Street,Chancheng District,presenting a cluster occurrence(RR=50.35,P<0.01). After implementing the restricted sale policy for live poultry,the GISA Moran’s I showed that the temporal epidemic characteristics of human infection with H7N9 avian influenza had been changed. The GISA Moran’s I showed that the H7N9 avian influenza epidemic in Foshan City was clustered from winter 2016 to spring 2017. LISA showed that Jiujiang Town in Naihai District was a"High-high"clustring area(LISA Moran’s I=5.58,P<0.01). Spatial-temporal scanning showed that the epidemic in twons of Jiujiang and Xiqiao was serious from December 2016 to January 2017(RR=25.10,P<0.05). Conclusion The spatial clustering and spatio-temporal clustering of human infection with H7N9 avian influenza in Foshan City were obvious. The epidemic characteristics were different before and after the implementations of the restricted sale policy for live poultry. Before implementing the policy,cases were occurred randomly,but there was a clusterring tendency in densely populated area. After implementing the policy,case cluster area was mainly in the place where the restricted sale policy for live poultry was not implemented.