| Part 1 Investigation of Virus Spectrum of Hospitalized Children with Acute Low Respiratory Infection from 2007-2008 in ChangshaObjectiveTo learn Common viral etiology of acute low respiratory tract infection among children in Changsha area, and provide basic data and scientific evidence of prevention and control with ALRTI.Subjects and Methods1. NPAs specimens were collected from children with acute low respiratory infections in Changsha area from September 2007 to August 2008.2. RSV, HRV, IFVA, IFVB, PIV1-3, hMPV, HCoV-NL63, HCoV-HKU1 were detected by RT-PCR methods; ADV and HBoV were tested by standard PCR methods; WUPyV and KIPyV were detected by nested-PCR methods. The amplicons were sequenced.3. Epedemiology and clinical manifestations of each virus in hospitalized children with ALRTI were analyzed.Results1. Among the 1165 NPAs samples, the total viruses detected rate was 74.76% (871/1165), RSV was the most common virus. The detected rate of RSV was 27.03%(315/1165), HRV was 17.33%(202/1165), PIV3 was 13.73%(160/1165), HBoV was 8.66%(101/1165), hMPV was 6.52%(76/1165), KIPyV was 5.92%(69/1165), ADV was 4.46%(52/1165), IFVB was 3.60%(42/1165), WUPyV was 13.51%(41/1165),IFVA was 1.97%(23/1165), the detected rate of HCoV-HKU1, HCoV- NL63, PIV1 and PIV2 were 1.03%(12/1165), 0.25%(3/1165), 0.17%(2/1165) and 0.60%(7/1165) respectively.2. The detected rate of males and females were 76.14%(581/763) and 72.13%(290/402) respectively, The detected rate was no significant difference between male and female(χ~2=2.241, P=0.134). The PIV3, hMPV and HBoV detected rate in male was higher than that in female, but no significant difference in male and female in other viruses.3. The median ages of viruses infected patients were 15.45±17.85 months (range from 1 day to 14 years). 75.37%(505/670)children with viruses infection were under 1 year old, 75.57%(263/348)children were at age from 1 year to 3 years old, 72.38%(76/105)children were at age from 3 years to 5 years old, 64.28%(27/42) children were older than 5 years old. The detected rate was significant difference in the age distribution(χ~2=10.934, P=0.027), especially in the age of 6 months～1 year old, and the age distribution of different viruses had differences.4. There was remarkable seasonal distribution of the detected rate of total viruses in Changsha area, the peak prevalence of viruses was in winter, and the peak seasonal distribution of different viruses had differences.Conclusions1. The total detected rate of viruses was 74.76% in our present study, which indicated viral infection is the main reason of children with ALRTI in Changsha area.2. Virus spectrum of ALRTI for hospitalized children in 2007-2008 in Changsha area was first reported. RSV, HRV and PIV3 were major causes of acute low respiratory tract infections in hospitalized children. In addition, recently identified HboV and hMPV also play important roles in ALRTI in Changsha.3. The detected rate was significant difference in the age distribution, especially in the age of 6 months～1 year old, and the age distribution of different viruses had differences. The detected rate was no significant difference between male and female, but the sex distribution of different viruses had differences. There was remarkable seasonal distribution of the detected rate of total viruses in Changsha area, the peak prevalence of viruses was in winter, and the peak seasonal distribution of different viruses had differences.Part 2 Prevalence Analysis of Human Metapneumovirus in Children with Acute Low Respiratory Infection from 2007-2008 in ChangshaObjectiveTo investigate the prevalence, clinical and genotype characteristics of hMPV in hospitalized children with ALRTI in Changsha, explore the difference between genotype and clinical characteristics, and provide evidence of prevention and control with ALRTISubjects and Methods1. NPAs specimens were collected from children with acute low respiratory infections in Changsha area from September 2007 to August 2008.2. Specimens were screened for hMPV M gene and F gene by RT-PCR, All positive amplification products were cloned into the pGEM-T Easy Vector and confirmed by sequencing.3. Sequences generated from the present study and reference sequences obtained from GenBank were determined and analyzed using the Dnastar software package. A neighbor-joining tree was constructed using the MEGA software package. Genotypes of hMPV were determined.4. Epedemiology and clinical manifestations of hMPV in hospitalized children with ALRTI were analyzed.5. explore the difference between genotypes and clinical characteristics.Results1. The detected rate of hMPV was 6.52%(76/1165).2. The sequence of positive products and standard sequences from GenBank shared high homology of 97%-100%. Single nucleotide mutation and nucleotide insertion were found, which indicated that the small speed of genetic variation. Phylogenetic analyses indicated that the 76 hMPV specimens were classified into the two main genetic lineages, A and B. Seventy-two (94.73%) hMPV strains were group A2, four (5.26%) strains were subgroup B2, and none were either subgroup A1 or B1. Among the A2 and B2 genotype strains, the sequence identities of F gene fragments were 86.06–87.15% and 81.14–82.46%, at the nucleotide and amino acid levels, respectively. The identities at the nucleotide and amino acid levels within subgroup A2 were 98.91–99.56% and 98.58–99.13%, and within subgroup B2 were 95.91–97.98% and 96.37–97.38%, respectively.3. The age of patients infected with hMPV varied from 20 days to 12 years of age (median, 15.87 months). The male:female rate in the hMPV-infected group was 3.47:1, The detected rate in male was higher than that in female.(χ~2=5.300, P<0.05) The majority of patients (63.15%) were under age of 1 year old. The number of positive specimens peaked in March and April, and no positive specimens were detected in August, September and October.4. 57.9%(44/76) hMPV positive children were found to be co-infected with other respiratory viruses, HBoV was the most common co-infecting virus and RSV was less common. No significant differences in ages, sex, fever, fever days, wheeze, vomiting, diarrhea, with and without underlying illnesses, hospitalized days between the hMPV mono- and coinfection groups were found.5. The clinical symptoms, signs and chest radiographs of infected hMPV patients were similar to that of other viruses. The main clinical diagnoses of patients who were hMPV-positive included bronchitis, bronchopneumonia, bronchiolitis, bronchial asthma and pneumonia, severe pneumonia and bronchitis, bronchopneumonia was the most common clinical diagnose.6. No significant differences in ages, sex, fever, vomiting, diarrhea, wheezing, crackles, with and without underlying illnesses and hospitalized days between the A and B genotype were found.Conclusions1. hMPV was an important viral pathogen in pediatric patients with ALRTI in Changsha.2. hMPV genetic variation occurred at a low speed. Only hMPV genotype A2 and B2 were co-circulating in this local, and A2 predominated. 3. The majority of children infected hMPV were less than 1 years old. The detected rate of boys was higher than girls. Positive specimens peaked in March and April in spring. The most were bronchopneumonia. The clinical characteristics of hMPV were similar to other viruses. The hMPV co-infection rate with other respiratory viruses was 57.89%, HBoV and RSV were the most common additional respiratory viruses.
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