Objective: To analyze the reasons for the fluctuations in the percentage of outpatient or emergency visits for influenza-like illness (ILI) during the Spring Festival and National Day in 2014-2018 surveillance season. Methods: ILI surveillance data was collected during the period of Spring Festival and National Day in mainland China, and downloaded from Chinese Influenza Surveillance Information System, during the 2014-2018 surveillance season. Results: There was no significant difference noticed in the number of ILI reports in the festival week with weeks before or after in both the southern and northern provinces. The number of outpatient visits was much less than that of the week before and after, but the number of emergency visits was statistically significantly increased. Conclusion: In the holiday peak of ILI%, the major causes was the impact of holiday-off at sentinel hospitals, resulting in a large reduction in the number of outpatient visits in the consulting room during the festivals.
Adolescent ; Adult ; Biometry ; Child ; Child, Preschool ; China/epidemiology* ; Disease Outbreaks/prevention & control* ; Emergency Service, Hospital/statistics & numerical data* ; Holidays ; Hospitals ; Humans ; Influenza, Human/virology* ; Outpatients/statistics & numerical data* ; Population Surveillance ; Respiratory Syncytial Virus Infections/virology* ; Respiratory Syncytial Virus, Human/isolation & purification* ; Respiratory Tract Infections/virology* ; Seasons ; Young Adult

OBJECTIVETo investigate the distribution of respiratory viruses on throat swabs in hospitalized children with acute lower respiratory tract infection (ALRTI).

METHODSA total of 5,150 children with ALRTI who were admitted to Hebei Children's Hospital between March 2014 and February 2015 were enrolled to investigate the distribution of respiratory viruses in children with ALRTI. Direct immunofluorescence assay was performed for throat swabs from these children to detect influenza virus A (FA), influenza virus B (FB), adenovirus (ADV), respiratory syncytial virus (RSV), and parainfluenza virus types 1, 2, and 3 (PIV-1, PIV-2, and PIV-3).

RESULTSOf all the 5,150 throat swabs from hospitalized children, 2,155 (41.84%) had positive virus detection results. RSV had the highest detection rate (1,338 cases/25.98%), followed by PIV-3 (439 cases/8.52%) and FA (166 cases/3.22%), and 29 patients had mixed infection with 2 viruses. With the increasing age, the detection rates of viruses tended to decrease (χ2=279.623; P<0.01). The positive rate of RSV increased gradually from September, and reached the peak value (60.09%) in November; the lowest positive rate occurred in June (1.51%). The positive rate of PIV-3 was the highest in May (21.38%) and the lowest in November (1.77%).

CONCLUSIONSThe distribution of viruses in children with ALRTI varies with age and season, with RSV prevalence in autumn and winter and PIV-3 prevalence in spring and summer. RSV is the most common viral pathogen that causes ALRTI in hospitalized children.

Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Orthomyxoviridae ; isolation & purification ; Parainfluenza Virus 3, Human ; isolation & purification ; Respiratory Syncytial Viruses ; isolation & purification ; Respiratory Tract Infections ; virology ; Seasons

OBJECTIVETo investigate the clinical epidemiologic characteristics and analyze risk factors for acute respiratory syncytial virus (RSV) infection in hospitalized infants with acute lower respiratory tract infection (ALRI).

METHODALRI infants admitted to Children's Hospital of Fudan University from March 1st, 2011 to February 29th, 2012, were enrolled in this study. Patient information included demographic characteristics, feeding history, family status, clinical presentation, accessory examination, treatment and prognosis. According to the etiology of ALRI infants, we compared the seasonal distribution, demographic characteristics, household characteristics and underlying diseases between RSV-positive patients and RSV-negative patients. Univariate and multiple Logistic regression analyses were used to determine factors that were associated with risk of RSV infection.

RESULTAmong 1 726 ALRI infants, there were 913 RSV-positive infants (52.9%). The occurrence of RSV infection had a seasonal variation, with a peak in winter (59.1%). The median (P25, P75) age of RSV infants was 64 (21-155) days. The gestational age (GA) and body weight (BW) was (37.5 ± 2.4) weeks and (3.07 ± 0.66) kg, respectively. The male/female ratio among these was 1.9: 1. RSV infection was more popular among infants in the families with smoking members, crowded living conditions, history of atopic mother. Differences of the proportion of patients with underlying disease between RSV-positive and negative groups were statistically significant (59.4% vs. 54.2%, P < 0.05). Univariate logistic regression demonstrated that factors increasing the risk of RSV infection were: GA<37 weeks (OR = 1.346, 95%CI: 1.037-1.748), birth weight <2 500 g (OR = 1.447, 95%CI: 1.103-1.898), underlying diseases (OR = 1.232, 95%CI: 1.018-1.492), underlying CHD (OR = 1.391, 95%CI: 1.120-1.728), environmental tobacco smoke exposure (OR = 1.254, 95%CI: 1.035-1.519), mother with atopic diseases (OR = 1.827, 95%CI: 1.296-2.573), crowded house with four or more than four family members (OR = 1.232, 95%CI: 1.013-1.498), autumn or winter infection (OR = 1.351, 95%CI: 1.024-1.783; OR = 1.713, 95%CI: 1.332-2.204). Multivariate logistic regression determined the factors increasing the risk of RSV infection were: underlying CHD (OR = 1.298, 95%CI: 1.002-1.681), mother with atopic diseases (OR = 1.766, 95%CI: 1.237-2.520), autumn or winter infection (OR = 1.481, 95%CI: 1.105-1.985; OR = 1.766, 95%CI: 1.358-2.296).

CONCLUSIONThe prevalence of RSV infection was the highest in winter, while preterm and low birth weight infants were more susceptible. Underlying diseases were found in 59.4% cases, CHD was the most common one. The factors increasing the risk of RSV infection were: CHD, mother with atopic diseases, autumn or winter infections.

Acute Disease ; China ; epidemiology ; Environmental Exposure ; adverse effects ; Female ; Hospitalization ; statistics & numerical data ; Humans ; Infant ; Infant, Newborn ; Logistic Models ; Male ; Prevalence ; Respiratory Syncytial Virus Infections ; epidemiology ; prevention & control ; Respiratory Syncytial Virus, Human ; isolation & purification ; Respiratory Tract Infections ; epidemiology ; prevention & control ; virology ; Retrospective Studies ; Risk Factors ; Seasons ; Socioeconomic Factors ; Tobacco Smoke Pollution

OBJECTIVETo elucidate the etiology of acute respiratory tract infection (ARI) in hospitalized children in Suzhou from 2005 to 2011.

METHODSA total of 10 243 hospitalized children with ARI in Children's Hospital Affiliated to Soochow University from September 2005 to October 2011 were enrolled in the study. The clinical information was collected; and the nasopharyngeal aspiration fluid and serum samples were sent for multi-pathogen detection. Respiratory syncytial virus (RSV), influenza virus type A and B (IV-A, IV-B), parainfluenza virus type 1-3 (PIV-1-PIV-3) and adenovirus (ADV) were detected by direct immunofluorescence assay. Human bocavirus (HBoV), mycoplasma pneumoniae (MP) and chlamydia pneumoniae (CP) were detected by fluorescent quantitative PCR while human metapneumovirus (hMPV) was detected by reverse transcription PCR (RT-PCR). Sputum culture was applied to detect bacterial infection and quantitative ELISA was adopted to detect the specific antibodies of MP and CP. The results of the above detections were analyzed, and thereby to explore the prevalent pathogens among different aging children and the seasonal distribution and characteristics of the disease.

RESULTSAt least one type of pathogen was detected in 5871 out of 10 243 hospitalized children and the overall positive rate was 57.32%; including 3326 virus samples with positive rate at 32.47% (3326/10 243), 2870 bacteria samples with positive rate at 28.02% (2870/10 243) and 2759 atypical pathogen samples,with positive rate at 26.94% (2759/10 243). MP was the most common pathogen,whose detected rate was 25.74% (2637/10 243). The median age of children with RSV (6 months) or PIV-3(8 months) infection was younger than the median age of all hospitalized children (12 months) (χ(2) = 380.992, 34.826, P < 0.05). While the median age of children with ADV (42 months), HBoV (14 months) or IV-A (24 months) infection was older than it of all hospitalized children (χ(2) = 83.583, 13.169, 18.012, P < 0.05). The median age of children with MP (30 months),streptococcus pneumoniae (17 months) or haemophilus parainfluenzae (21 months) infection was older than it of all hospitalized children (χ(2) = 728.299, 60.463, 8.803, P < 0.05). The detected rate of RSV in the groups of children aging less than 6 months, 7-12 months, 2-3 years, 4-5 years and over 6 years was separately 25.59% (840/3283), 17.05% (333/1953), 11.85% (310/2615), 6.68% (90/1347), and 2.87% (30/1045); which decreased while the age grew (χ(2) = 178.46, P < 0.01). Conversely, the positive rate of MP increased with the age growing (χ(2) = 379.21, P < 0.01). The rate in the above groups was 8.25% (271/3283), 19.46% (380/1953), 33.00% (863/2615), 41.43% (558/1347), 54.07% (565/1045), respectively. RSV and IV-A were prevalent in winter, whose detected rates were 35.73% (941/2634) and 4.44% (117/2634) respectively.hMPV infection was common in spring, with the detected rate at 10.55% (278/2634); while HBoV infection was common in summer and autumn, with the positive rate at 9.99% (149/1491) and 9.71% (98/1009). MP and CP were frequently detected in summer, up to 31.27% (819/2619) and 10.07% (43/427) respectively. RSV was the most common pathogen in bronchiolitis (33.27% (866/2603)) and MP was the most common pathogen in bronchopneumonia (26.05% (1152/4422)) and lober pneumonia (52.25% (267/511)).

CONCLUSIONMP and RSV were the most common pathogens in respiratory tract infection in hospitalized children. The novel virus included hMPV and HBoV, which also played an important role in ARI. Different pathogens were prevalent in different ages; with respective seasonal distribution and characteristics.

Acute Disease ; Adolescent ; Child ; Child, Hospitalized ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Male ; Mycoplasma pneumoniae ; isolation & purification ; Respiratory Syncytial Virus, Human ; isolation & purification ; Respiratory Tract Infections ; epidemiology ; microbiology ; virology ; Seasons

OBJECTIVETo investigate the infection status and epidemiological characteristics of influenza virus and respiratory syncytial virus (RSV) in influenza-like illness (ILI) of children ( ≤ 14 years) in Wuhan area from 2008 to 2012.

METHODSA total of 2854 cases of ILI patients ( ≤ 14 years) in a hospital of Wuhan were recruited in the study from July 2008 to June 2012. The sample of pharyngeal swab was collected from each patient, to extract the virus nucleic acids. Real-time fluorescent quantitation reverse transcription PCR (RT-PCR) method was applied to detect the subtypes of influenza virus and RSV, and then analyzed the time and age characteristics.

RESULTSOut of the 2854 cases, 758 (26.6%) were positive for influenza virus,including 547 (19.2%) influenza A virus positive samples and 211 (7.4%) influenza B virus positive samples. Usually, there were two peaks present in the annual curve of influenza virus, namely summer peak and winter/spring peak. The positive rate of influenza virus in 6-14 years old children (48.0%, 275/573) was significantly higher than that in 3-5 years old children (26.6%, 213/801) and that under 3 years old children (18.3%, 270/1480). The difference showed statistical significance (χ(2) = 187.432, P < 0.01). A total of 219 (7.7%) cases were positive for RSV,including 108 RSV-A positive samples and 112 RSV-B positive samples (1 co-infection). The epidemic of RSV showed an obvious seasonal pattern with peaks in autumn,winter and spring,which accounted for 96.8% (212/219) of all the cases; however, the annual incidence of RSV fluctuated greatly. The predominant subtype shifted every 2 years. RSV-B predominated during September 2008 and May 2009, December 2009 and March 2010, accounting for 76.6% (36/47) and 96.9% (62/64) respectively. RSV-A predominated during November 2010 and March 2011, September 2011 and April 2012, accounting for 92.5% (37/40) and 100.0% (48/48) respectively. With the increase of the age, the positive rate of RSV-A and RSV-B decreased gradually (RSV-A: χ(2) = 36.223, P < 0.01; RSV-B: χ(2) = 36.281, P < 0.01). The positive rates of RSV-A in children < 1,1,2,3,4,5-9 and 10-14 years old were 7.0% (26/373), 5.9% (39/662), 4.0% (18/445), 3.2% (13/406), 1.3% (3/236), 1.4% (7/517) and 0.9% (2/215) respectively; while, the positive rates of RSV-B in each age group were 6.4% (24/373), 6.0% (40/662), 4.5% (20/445), 4.4% (18/406), 1.3% (3/236), 1.0% (5/517) and 0.9% (2/215) respectively. The children aged 0-3 years old were more susceptible for RSV infection,accounting for 90.0% (197/219) of the total positive samples. During the outbreak of influenza A H1N1 in November 2009, the positive rate of RSW was 3.0% (3/100), lower than that in the same month of 2008, 2010 and 2011,which were separately 18.2% (6/33), 10.8% (10/93) and 10.0% (4/40). The difference showed statistical significance (χ(2) = 8.450, P < 0.05). During the outbreak of influenza A (H1N1) in January 2011,the positive rate of RSV was 5.7% (3/53), lower than those in the same month of 2009, 2010 and 2012, which was separately 21.7% (5/23), 28.6% (22/77) and 16.0% (8/50). The difference showed statistical significance (χ(2) = 11.233,P < 0.05). During the period of less influenza happened in September 2011, the RSV positive rate was 25.0% (10/40), higher than those in the same month of 2008, 2009 and 2010, which was separately 11.4% (4/35), 1.7% (2/118) and 0.0% (0/109). The difference showed statistical significance (χ(2) = 32.521, P < 0.01).

CONCLUSIONBoth influenza virus and RSV were important etiological agents of ILI of children in Wuhan. The characteristics of seasonal and age distributions of the two viruses were notably different; meanwhile, a certain inhibitional effect of influenza virus on RSV could be observed.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Influenza, Human ; epidemiology ; Male ; Orthomyxoviridae ; classification ; isolation & purification ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Viruses ; classification ; isolation & purification

This study was performed to characterize respiratory viral infections in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). Study samples included 402 respiratory specimens obtained from 358 clinical episodes that occurred in the 116 children of the 175 consecutive HSCT cohort at Seoul National University Children's Hospital, Korea from 2007 to 2010. Multiplex reverse-transcription polymerase chain reactions were performed for rhinovirus, respiratory syncytial virus (RSV), parainfluenza viruses (PIVs), adenovirus, human coronavirus (hCoV), influenza viruses and human metapneumovirus. Viruses were identified in 89 clinical episodes that occurred in 58 patients. Among the 89 clinical episodes, frequently detected viruses were rhinovirus in 25 (28.1%), RSV in 23 (25.8%), PIV-3 in 16 (18.0%), adenovirus in 12 (13.5%), and hCoV in 10 (11.2%). Lower respiratory tract infections were diagnosed in 34 (38.2%). Neutropenia was present in 24 (27.0%) episodes and lymphopenia was in 31 (34.8%) episodes. Sixty-three percent of the clinical episodes were hospital-acquired. Three patients died of respiratory failure caused by respiratory viral infections. Respiratory viral infections in pediatric patients who have undergone HSCT are common and are frequently acquired during hospitalization. Continuous monitoring is required to determine the role of respiratory viruses in immunocompromised children and the importance of preventive strategies.
Adenoviridae/genetics/isolation & purification ; Adolescent ; Adult ; Child ; Child, Preschool ; Cohort Studies ; Coronavirus/genetics/isolation & purification ; Female ; *Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells/cytology ; Hospitalization ; Humans ; Infant ; Lymphopenia/epidemiology ; Male ; Neutropenia/epidemiology ; Parainfluenza Virus 3, Human/genetics/isolation & purification ; Prevalence ; Respiratory Syncytial Viruses/genetics/isolation & purification ; Respiratory Tract Infections/epidemiology/therapy/*virology ; Reverse Transcriptase Polymerase Chain Reaction ; Rhinovirus/genetics/isolation & purification ; Seasons ; Young Adult

OBJECTIVETo establish a rapid, sensitive and specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for detecting human respiratory syncytial virus (RSV) in respiratory samples collected from children with acute respiratory infections.

METHODAccording to the conserved matrix gene sequences of respiratory syncytial virus subtypes A and B downloaded from GenBank, primers were designed and RT-LAMP assay was developed to detect RNA of RSV sensitivity of the RT-LAMP method was evaluated by using ten-fold serially diluted in vitro-transcribed matrix RNA fragments from RSV A and RSV B, respectively. Specificity of the RT-LAMP method was tested through cross-reaction with other RNA and DNA viruses. Then 5 RSV strains isolated from clinical specimens using tissue cultures were tested by RT-LAMP assay. A total of 101 nasopharyngeal aspirates from hospitalized patients with acute respiratory infections which had been tested by direct immunofluorescence assay (DFA), including 40 positive for RSV and 61 negative for RSV, were tested by RT-LAMP assay and by RT-nested PCR.

RESULTSensitivity analysis indicated that this RT-LAMP method was able to detect 1 copy/µl of RSV A and RSV B RNA, no amplification was shown in RT-LAMP with DNA or cDNA from other viruses in 60 min, revealed that the RT-LAMP assay is highly specific. Five RSV isolates confirmed as 4 RSV A and 1 RSV B previously were detected by RT-LAMP method as positive in 30 min. For those 101 specimens tested, 37 were RSV positive determined by RT-LAMP assay, as well as 35 RSV positive by RT-nested PCR. The total coincidence rate of RT-LAMP assay with DFA and RT-nested PCR in detecting RSV is 95.0%, 94.1% with Kappa value 0.895 and 0.871, respectively.

CONCLUSIONA new, sensitive, accurate and rapid method, RT-LAMP assay for detecting human respiratory syncytial viruses from nasopharyngeal aspirates was developed, which should be helpful in rapid detection of RSV from respiratory tract samples of children.

Acute Disease ; Child ; Child, Preschool ; DNA Primers ; Humans ; Infant ; Molecular Diagnostic Techniques ; Nasopharynx ; virology ; Nucleic Acid Amplification Techniques ; RNA, Viral ; isolation & purification ; Respiratory Syncytial Virus Infections ; diagnosis ; Respiratory Syncytial Virus, Human ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sensitivity and Specificity

OBJECTIVEAcute respiratory tract infections (ARI) are the leading cause of pediatric morbidity and mortality worldwide, particularly in developing countries. Viruses are the main pathogens of ARI in children. The purpose of the present study was to determine the epidemiologic features of respiratory viruses, including novel viruses, in outpatient and hospitalized children with ARI.

METHODFrom March 2010 to February 2012, 2066 children with ARI, including 1050 outpatients and 1016 inpatients, were involved in this study. One nasopharyngeal aspirate or throat swab specimen was collected from each patient. Reverse transcription (RT) PCRs were performed to detect common respiratory tract viruses including respiratory syncytial virus (RSV), human rhinovirus (HRV), influenza virus (IFV), parainfluenza virus (PIV) type 1-4, adenovirus (ADV), enterovirus (EV), human coronavirus (HCOV), human metapneumonia virus (HMPV) and human bocavirus (HBOV).

RESULTAt least one viral pathogen was identified in each of 1274 out of 2066 patients and the overall positive rate was 61.7%. The positive rate in inpatient (69.7%) was higher than that in outpatient (53.9%). The frequencies of detection of various viruses among in- and outpatients were different. RSV was the most prevalent virus detected among hospitalized children, followed by HRV and PIV, whereas IFV was the most frequently identified virus in the outpatient group, followed by ADV and PIV. Simultaneous detection of two or more viruses was found in 377 cases. Coinfection was more frequent in inpatients than in outpatients (30.1% vs. 6.8%, P < 0.001).

CONCLUSIONRespiratory viruses play an important role in children with ARI, especially in young children. RSV was the most prevalent virus detected among hospitalized children, whereas IFV was the most frequently identified virus in the outpatient group. Viral coinfections are frequently identified, particularly in hospitalized patients. Further studies are required to better understand the impact of coinfections in children with ARI.

Acute Disease ; Age Distribution ; Child ; Child, Hospitalized ; Child, Preschool ; China ; epidemiology ; Coinfection ; epidemiology ; virology ; DNA Viruses ; isolation & purification ; Female ; Humans ; Infant ; Male ; Nasopharynx ; virology ; Outpatients ; Parainfluenza Virus 1, Human ; isolation & purification ; Parvoviridae Infections ; epidemiology ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Virus, Human ; isolation & purification ; Respiratory Tract Infections ; epidemiology ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; Rhinovirus ; isolation & purification ; Seasons

OBJECTIVETo investigate the viral etiology and clinical features of hospitalized children with acute respiratory tract infections in Tibet.

METHODNasopharyngeal aspirate samples were collected from children with acute respiratory tract infection hospitalized at the department of Pediatrics, Tibet Autonomous Region People's Hospital from April to July, 2011. The specimens of nasopharyngeal aspirate were screened for antigens of 7 common respiratory viruses by direct immunofluorescence (DIF) [respiratory syncytial virus (RSV), adenovirus (ADV), parainfluenza viruses type I-III, influenza virus A and B] and human metapneumovirus. Clinical data of the children were analyzed by statistical software SPSS16.

RESULTA total of 167 children with acute respiratory tract infections hospitalized from April to July 2011 were enrolled in this investigation. Sixty-five out of 167 specimens were positive for viral antigens. The virus positive rate for specimens was 38.9% (65/167). Two of 65 positive specimens were positive for 2 virus antigens (RSV + influenza B) and (hMPV + parainfluenza virus type III), respectively. RSV was detected in 45 cases (67.2%, 45/67) which was the most predominant, followed by parainfluenza virus type III detected in 7 cases (10.4%, 7/67), ADV in 6 cases (9.0%, 6/67), parainfluenza virus type I in 4 cases (6.0%, 4/67), influenza virus type B in 3 cases (4.5%, 3/67), and hMPV in 2 cases (3.0%, 2/67). In addition to clinical manifestations of pneumonia, such as cough and shortness of breath, only 3 virus positive cases (6.67%) presented with wheezing, but the signs of severe cyanosis, fine rales in lung were common. Most of the children in this study recovered soon, only a few younger children with underlying diseases or complications had severe illness.

CONCLUSIONVirus is an important pathogen for acute respiratory infections for hospitalized children in Tibet. RSV was the most predominant etiological agent, especially for those younger than 3 years old.

Acute Disease ; Adolescent ; Age Distribution ; Child ; Child, Hospitalized ; Child, Preschool ; Female ; Fluorescent Antibody Technique, Direct ; Humans ; Infant ; Male ; Nasopharynx ; virology ; Respiratory Syncytial Virus Infections ; epidemiology ; pathology ; virology ; Respiratory Syncytial Virus, Human ; isolation & purification ; Respiratory Tract Infections ; epidemiology ; pathology ; virology ; Tibet ; epidemiology ; Virus Diseases ; epidemiology ; etiology ; pathology ; virology ; Viruses ; classification ; isolation & purification

OBJECTIVEViruses are common pathogens of acute lower respiratory tract infection (ALRTI) in children. There are few studies on consecutive monitoring of viral pathogens of ALRTI in a larger cohort during the past several years. The aim of this study was to investigate the viral pathogens of ALRTI in children of different age groups and to outline the epidemic feature of different viruses.

METHOD(1) Totally 1914 (1281 male and 709 female) children with clinical diagnosis of ALRTI during the period of March 2007 to March 2010 were recruited into this study. These patients were hospitalized patients in department of internal medicine or outpatients in emergency department in Beijing Children's Hospital. The patients were divided into four groups, including 1072 patients < 1 year old, 326 patients 1- < 3 years old, 158 patients 3- < 6 years old, 358 patients ≥ 6 years old. One nasopharyngeal aspirate specimen was collected from each patient. Reverse transcription (RT) PCR methods were applied to detect common respiratory viruses including respiratory syncytial virus (RSV), human rhinovirus (HRV), influenza virus type A, B and C (IFA, IFB, IFC), parainfluenza virus (PIV) type 1-4, adenovirus (ADV), enterovirus (EV), human coronavirus (HCOV), human metapneumovirus (HMPV) and human bocavirus (HBOV).

RESULT(1) The total positive rate of viruses was 70.3%. The positive rate was 83.0% (890/1072) in the group of < 1 year old, and 80.1% (261/326) in group of 1- < 3 years old, 60.8% (96/158) in group of 3- < 6 years old and 27.7% (99/358) in group of ≥ 6 years old, respectively. There was a significant difference in the positive rate among different age groups (χ² = 2213.5, P = 0.000). The top three viruses were RSV, HRV and PIV; and the positive rates were 50.9%, 36.2% and 12.0% respectively in group of < 1 year old. (2) The epidemic seasons of RSV and HRV were winter and spring, and PIV infection was epidemic in spring and summer. (3) The detection rates of 2 or more viruses were 38.2%, 36.4%, 30.2% and 15.2% in groups of < 1 year old, 1- < 3 years old, 3- < 6 years old and ≥ 6 years old, respectively. There was a significant difference in the mixed infection rate among different age groups (χ² = 1346.00, P = 0.000).

CONCLUSIONRSV, HRV and PIV were the most predominant pathogens in younger children with ALRTI. Different viral infections had different seasonal features. Mixed infections with two or more viruses were detected in substantial proportion of patients with ALRTI, but further studies are needed to explore the clinical significance of mixed infection with viruses in patients with ALRTI.

Acute Disease ; Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Human bocavirus ; isolation & purification ; Humans ; Infant ; Male ; Parainfluenza Virus 1, Human ; isolation & purification ; Parvoviridae Infections ; epidemiology ; virology ; Respiratory Syncytial Virus Infections ; epidemiology ; virology ; Respiratory Syncytial Virus, Human ; isolation & purification ; Respiratory Tract Diseases ; epidemiology ; virology ; Respirovirus Infections ; epidemiology ; virology