对昆明地区2003—2007年儿童嗜肺军团菌1型(LP1)感染所致儿童急性下呼吸道感染(ALRI)的状况进行临床及流行病学调査研究。

选择2003—2007年在昆明市儿童医院住院治疗的12 083例ALRI患儿为研究对象，应用间接荧光测定法(IFA)进行血清LP1-IgM检测，对2003—2007年ALRI患儿的LP1感染阳性率的性别、年龄及季节差异进行比较，分析LP1感染的临床特征及流行概况(本研究遵循的程序符合昆明市儿童医院人体试验委员会制定的伦理学标准，得到该委员会批准)。

本研究结果为：①2003—2007年ALRI患儿的LP1感染总阳性率为11.3%(1 365/12 083)；5年间的LP1感染呈阳性患儿的比较，差异有统计学意义(χ² = 12.6，P<0.05)。②LP1感染呈阳性患儿的性别比较，差异无统计学意义(χ² =3.5，P>0.05)；0~1岁、>1~3岁、>3~6岁及>6岁各年龄段LP1感染率比较，差异有统计学意义(χ²=431.5，P<0.01)，LP1感染率有随年龄增长而呈增高的趋势。③LP1感染的临床特点包括：感染早期均以发热、咳嗽多见，临床无特异表现，可伴混合感染及肺外器官和系统损伤，大环内酯类抗菌药物治疗对其有效。④2003—2007年LP1在一年的4个季节的感染率比较，差异均有统计学意义(χ² =40.0，P<0.05)，且春季LP1感染率均低于夏、秋、冬季，其差异均有统计学意义(χ²=31.1，34.2,18.6;P<0.05);除2006年外，每年不同季节LP1感染阳性率比较，差异有统计学意义(χ² = 10.6，10.5,14.5,10.7；P<0.05)。

LP1感染是昆明地区年长儿ALRI的重要病原体，LP1感染儿童性别比较无差异；临床以发热、咳嗽多见，可伴混合感染及肺外器官和系统损伤；昆明地区2003 — 2007年春季LP1感染率较其他季节LP低。

To investigate Legionella pneumophila type 1 (LP1) infection status in children in Kunming and analyze its clinical features and epidemiological characteristics from 2003 to 2007.

LP1 antibody IgM with 12 083 serum specimens collected from children who caught acute lower respiratory infection (ALRI) from 2003 to 2007 in Kunming Children's Hospital were detected by indirect immunofluorescence (IFA). The differences of the gender, age and season distribution characteristics of LP1 infection from 2003 to 2007 were statistically compared. At the same time, clinical features and epidemic characteristics of LP1 infection were analyzed. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Kunming Children's Hospital.

The results were:①The total positive rate of LP1 infection was 11.3% (1 365/12 083) from 2003 to 2007; and the positive rate of LP1 infection in this five years had statistically significant differences(χ² = 12.6,P<0.05). ②The positive rate of LP1 infection in gender had no statistically significant differences (χ² = 3.5, P> 0.05) ;and the positive rate of LP1 infection in different age stages (younger than 1 year old, more than 1-3 years old, more than 3-6 years old, more than 6 years old) had statistically differences(χ² =431.5,P< 0.01),showing an increasing trend with age.③The main clinical features of LP1 infection were fever and cough in early period, with no-specific symptoms and maybe with mixed infections, extrapulmonary organ and system damage. Macrolides antibacterial drug therapy were effective.④The total positive rate of LP1 infection among four seasons from 2003 to 2007 had statistically significant differences(χ² =40.0,P< 0.05), and the total positive rate in spring was statistically lower than that of in summer, autumn and winter (χ² = 31.1, 34.2, 18.6; P<0.05); The positive rate of LP1 infection in four seasons had statistically differences of each year except the year of 2006(χ² = 10.6, 10.5,14.5,10.7; P<0.05).

LP1 infection was an important pathogen to children with ALRI in Kunming, and had no gender difference. The main symptoms of LP1 were fever, cough, mixed infection and damage extrapulmonary organ. The total positive rate of LP1 infection in spring were lower than that of other three seasons in Kunming from 2003 to 2007.