Objectives: To investigate the epidemiological characteristics of respiratory Haemophilus influenzae (HI) infection in children in Suzhou, China and its association with climatic factors and air pollutants.
Methods: The data on air pollutants and climatic factors in Suzhou from January 2016 to December 2019 were collected. Respiratory secretions were collected from 7 940 children with acute respiratory infection who were hospitalized during this period, and bacterial culture results were analyzed for the detection of HI. A stepwise regression analysis was used to investigate the association of HI detection rate with air pollutants (PM2.5, PM10, NO2, SO2, CO, and O3) and climatic factors (monthly mean temperature, monthly mean humidity, monthly total rainfall, monthly total sunshine duration, and monthly mean wind speed).
Results: In 2016-2019, the 4-year overall detection rate of HI was 9.26% (735/7 940) among the children in Suzhou. The children aged <1 year and 1-<3 years had a significantly higher HI detection rate than those aged ≥3 years (P<0.01). The detection rate of HI in spring was significantly higher than that in the other three seasons, and the detection rate of HI in autumn was significantly lower than that in the other three seasons (P<0.001). The multiple linear regression analysis showed that PM10 and monthly mean wind speed were independent risk factors for the detection rate of HI: the detection rate of HI was increased by 0.86% for every 10 µg/m3 increase in the concentration of PM10 and was increased by 5.64% for every 1 m/s increase in monthly mean wind speed. Air pollutants and climatic factors had a lag effect on the detection rate of HI.
Conclusions: HI is an important pathogen for acute respiratory infection in children in Suzhou and is prevalent in spring. PM10 and monthly mean wind speed are independent risk factors for the detection rate of HI.
目的: 探讨苏州地区住院儿童呼吸道感染流感嗜血杆菌（Haemophilus influenzae，HI）的流行特征及其与气候因素和空气污染物的相关性。方法: 收集2016年1月—2019年12月苏州地区空气污染物和气候因子相关检测数据，并与同期7 940例急性呼吸道感染住院患儿呼吸道分泌物细菌培养HI检出情况进行比较，采用逐步回归法分析HI检出率与空气污染物（PM2.5、PM10、NO2、SO2、CO、O3）及气候因素（月平均气温、月平均湿度、月总雨量、月总日照、月平均风速）的相关性。结果: 2016—2019年苏州地区住院儿童HI总检出率为9.26%（735/7 940）。<1岁组和1~<3岁组HI检出率均明显高于≥3岁组，差异有统计学意义（均P<0.01）。春季HI检出率明显高于其他3季，秋季HI检出率明显低于其他3季，差异均有统计学意义（均P<0.001）。多元线性回归分析显示PM10和月平均风速为HI检出率的独立危险因素，其中PM10浓度每增加10 μg/m3，HI检出率增加0.86%；月平均风速每增加1 m/s，HI检出率增加5.64%。空气污染物和气候因素对HI检出率存在滞后效应。结论: HI是苏州地区住院儿童急性呼吸道感染重要病原体，春季流行；PM10和月平均风速为HI检出率的独立危险因素。.
Keywords: Air pollutant; Child; Climatic factor; Haemophilus influenzae; PM 10; Respiratory infection.