Clinical features of children infected with influenza virus A in year 2009 in Wuhan area / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the clinical and pandemic features and respiratory pathogen co-infection characteristics of children infected with influenza virus A (Flu A) in year 2009.Methods A retrospective study of hospitalized children with flu-like clinical symptoms in 2009 was conducted.The peripheral blood serum was analyzed to detect common respiratory agents,inclucding Flu A,respiratory syncytial virus,adenovirus,influenza virus B,parainfluenza virus 1,2 and 3,chlamydia pneumonia and mycoplasma pneumonia,klebsiella pneumonia (KP),haemophilus influenza and legionella pneumophila by using indirect immunofluorescence test for the antibody detection (IgM).And a standard medical history was recorded,including epidemiological data,clinical manifestation,and the length of hospital stay,white blood count and chest X-ray elsewhere.All specimens were collected in Department of Pediatrics,Zhongnan Hospital of Wuhan University,from Jan.2009 to Dec.2009.Results Flu A was detected in 234 of the 599 (39.1％,234/599 cases) flu-like children.The mean age was 48.8 months (range from 3 to 167 months).The detection rate in less than 1-year-old group (11.1％,18/162 cases) was obviously lower than that of the older groups (P ＜ O.001).Especially for the group ＜ 6 months,there was only 1 infant (1.43％,1/70 cases) with Flu A positive.Compared with Flu A negative group,the main clinical features of children with Flu A positive group were fever(78.2％,183/234 cases,P =0.013) and cough(76.5％,179/234 cases,P =0.04),however asthma (14.1％,33/234 cases,P =0.003)and diarrhea (6.0％,14/234 cases,P ＝ 0.001) cases were less.The detection rates of Flu A reached a peak of 57.0％ in November and December,and a secondary peak of 45.0％ in May and June.Flu A infection children less than 1 year old were simple in etiology.The children were older,the etiology was more complex.The primary coinfection pathogen was KP (53.8％,126/234 cases) and Flu B(48.3％,113/234 cases).Compared Flu A coinfection with or without KP,there was no difference between these 2 groups in the clinical features.Conclusions Intfluenza A is the main pathogen of hospitalized children with flu-like symptoms in 2009.Children over 1 year old age were the major infection groups of Flu A.The detection rates of Flu A reached peaks in May to June and November to December.Flu A positive children were prone to KP coinfection.