ABSTRACT
BackgroundTo clarify the characteristic and the duration of positive nucleic acid in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including asymptomatic children. MethodsA total of 32 children confirmed with SARS-CoV-2 infection between January 24 and February 12, 2020 from four provinces in Western China were enrolled in this study and followed up until discharge and quarantine 14 days later. ResultsEleven children (34%) were asymptomatic, among whom six children had normal computed tomographic (CT) scan images. Age and gender were not associated with clinical symptoms or the results of CT scan in children infected with SARS-CoV-2. The concentrations of white blood cells and neutrophils were higher in children with asymptomatic infection than in children with clinical symptoms or CT abnormalities. Patients who presented with CT abnormalities had lower D-dimer or lower total bilirubin than those who had normal CT scan but clinical symptoms. All children recovered and no one died or was admitted to the pediatric intensive care unit (PICU). The mean duration of positive SARS-CoV-2 nucleic acid was 15.4 (SD=7.2) days and similar for both asymptomatic children and children with symptoms or CT abnormalities. We found a significant negative correlation between the lymphocyte count and the duration of positive nucleic acid test. ConclusionsChildren with asymptomatic infection should be quarantined for the same duration as symptomatic patients infected with SARS-CoV-2. The clinical significance and mechanism behind the negative correlation between the number of lymphocytes and the duration of positive SARS-CoV-2 needs further study.
ABSTRACT
Objective To provide reference for anti-infection drugs in Zunyi area by analyzing the etiological characteristics of children with severe pneumonia.Methods The sputum, throat swabs and serum of children with severe pneumonia in pediatric intensive care unit of our hospital from January 2014 to December 2015 were collected in this study.The pathogen species which caused severe pneumonia were detected and identified by the method of pathogen culture,and typical pathogens were detected by RT-PCR and indirect immunofluorescence.Results A total of 337 children with severe pneumonia were included,the pathogen positive rate was 86.65%(292/337).The rate of viral infection(37.32%)was the highest,followed by bacterial infection accounting for 28.42%,then the mixed infection accounting for 27.74%,and the mycoplasma pneumoniae infection accounting for 6.50%.The respiratory syncytial virus type B accounting for 28.44% was the most common in viral infection,and there were significant differences in age distribution(P<0.05),the children under 3-years-old,especially the infants under 1-year-old had the highest susceptibility.Viral infection had certain seasonality,compared with spring and winter,autumn and winter(November to April) had higher viral detection rate and the difference was statistically significant(x2=29.28,P=0.001).The escherichia coli was the most common in bacterial infection,accounting for 21.69%.Klebsiella pneumoniae,Escherichia coli were more common in neonates and infants under 1-year-old,Haemophilus influenzae occured in 1~3 years old children,Streptococcus pneumoniae infection could occur in any age.Conclusion Viral infection is the most common pathogen in children with severe pneumonia in Zunyi area followed by bacterial infection,which is more common in children under 1-year-old,and with the high incidence in autumn and winter.Bacterial infection is more common in children over 3 years of age.Bacterial and viral mixed infection is common in children under 3 years of age,especially in children under 1-year-old.
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Objective To inquire into the molecular epidemiology of enterovirus 71 ( EV71 ) in our region by analyzing the whole genome characteristics and genetic evolution of EV 71 strains isolated from Guizhou area. Methods The throat swabs samples of hospitalized children with hand,foot and mouth disease in Guizhou province from 2013 to 2015 were collected,the virus nucleic acid were extracted,then the whole genome of virus were piecewise amplified by reverse transcription polymerase chain reaction( RT-PCR) and sequenced. Sequencing results were edited and spliced by DNAMAN8. 0 software,then the viral genome se-quences were compared with genome sequences of other EV71 strains in the genebank by Blastn,the phyloge-netic tree was constructed by the Neighbor-Joining method in MEGA5. 2 software. Results The whole ge-nome sequences of 17 EV71 strains were successfully isolated and amplified,the whole genome length of 17 EV71 isolates was 7405 base pair,encoded about 2193 amino acids. The 17 isolates were divided into ten species of amino acid sequences by 12 differences of amino acid among the strains,different sequences and clinical types had not shown regularity and correlation. The nucleotide homology in VP1 region,5′untranslat-ed region(5′UTR) and 3′untranslated region (3′UTR) were high among 17 EV71 isolates. The results that the whole genome of 17 EV71 isolates was compared with representative strains of EV71 A,B,C genotype and coxsakievirus A 16 ( CA16) showed that 17 EV71 isolates had higher homology with EV71 C4a sub-type,95. 3%-98. 1%,and the lowest homology with CA16. The phylogenetic tree was constructed based on nucleotide sequence of the whole genome,VP1 region and 5′untranslated region of 17 isolates showed that the 17 isolates were clustered into one cluster,and were clustered in the same branch with C4a isoforms,the phy-logenetic relationships among different regions were different. Conclusion The popular genotype of EV71 strains in Guizhou area for 2013-2015 was C4a subtype,consistenting with the genotype of popular EV71 in other regions of China. EV71 strains hasn′t the antigen transformation and input of a new subtype temporari-ly,but exist nucleotide and amino acid changes,so need be chronically and dynamically monitored. There is no correlation between the amino acid sequence difference of 17 EV71 isolates and the state of an illness.
ABSTRACT
Objective To inquire into the molecular epidemiology of enterovirus 71 ( EV71 ) in our region by analyzing the whole genome characteristics and genetic evolution of EV 71 strains isolated from Guizhou area. Methods The throat swabs samples of hospitalized children with hand,foot and mouth disease in Guizhou province from 2013 to 2015 were collected,the virus nucleic acid were extracted,then the whole genome of virus were piecewise amplified by reverse transcription polymerase chain reaction( RT-PCR) and sequenced. Sequencing results were edited and spliced by DNAMAN8. 0 software,then the viral genome se-quences were compared with genome sequences of other EV71 strains in the genebank by Blastn,the phyloge-netic tree was constructed by the Neighbor-Joining method in MEGA5. 2 software. Results The whole ge-nome sequences of 17 EV71 strains were successfully isolated and amplified,the whole genome length of 17 EV71 isolates was 7405 base pair,encoded about 2193 amino acids. The 17 isolates were divided into ten species of amino acid sequences by 12 differences of amino acid among the strains,different sequences and clinical types had not shown regularity and correlation. The nucleotide homology in VP1 region,5′untranslat-ed region(5′UTR) and 3′untranslated region (3′UTR) were high among 17 EV71 isolates. The results that the whole genome of 17 EV71 isolates was compared with representative strains of EV71 A,B,C genotype and coxsakievirus A 16 ( CA16) showed that 17 EV71 isolates had higher homology with EV71 C4a sub-type,95. 3%-98. 1%,and the lowest homology with CA16. The phylogenetic tree was constructed based on nucleotide sequence of the whole genome,VP1 region and 5′untranslated region of 17 isolates showed that the 17 isolates were clustered into one cluster,and were clustered in the same branch with C4a isoforms,the phy-logenetic relationships among different regions were different. Conclusion The popular genotype of EV71 strains in Guizhou area for 2013-2015 was C4a subtype,consistenting with the genotype of popular EV71 in other regions of China. EV71 strains hasn′t the antigen transformation and input of a new subtype temporari-ly,but exist nucleotide and amino acid changes,so need be chronically and dynamically monitored. There is no correlation between the amino acid sequence difference of 17 EV71 isolates and the state of an illness.
