Etiological Study Of Enteric Viruses In Acute Diarrhea Children In2012, Chongqing

Objective: Studying acute viral diarrhea in pediatric patients inChongqing may provide basic data and a theoretical foundation forformulating a strategy to prevent and control viral diarrhea.Methods: Diarrhea specimens in384infants with suspected viraldiarrhea between January2012and December2012in Chongqing regionwere collected, and the clinical data were recorded. Colloidal Gold wasused for the detection of group A rotavirus (RV). RT-PCR was used fornucleic acid detection of norovirus (NV), sapovirus (SV), and astrovirus(ASV). PCR was adopted for nucleic acid detection of human adenovirus(HAdV). All positive samples were purified and sequenced.The obtainedsequences were aligned by DNAstar. A phylogenetic tree was establishedusing MEGA5.05software, with Kimura’s2-parameter method used tocalculate the genetic distance, and the neighbor-joining method withboot-strap repeated1,000times.In addition, potential NV recombinantstrains need to be identified.Results: Among the384studied pediatric patients with acute diarrhea(248males and136females),283had positive virus tests, accounting for 73.70%(283/384) of specimens assessed. One hundred and eighty-sixyoung males had positive test results, showing a positive rate of75.00%(186/248), while97young females had positive test results, showing apositive rate of71.32%(97/136). Statistical analysis did not demonstrate astatistically significant difference in the risk of viral diarrhea between the2genders (χ2=0.612, P>0.05).Diarrhea virus-positive rates were44.27%(170/384, RV),21.88%(84/384, NV),10.16%(39/384, HAdV),7.81%(30/384, ASV), and6.77%(26/384, SV), respectively. Mixed infectionaccounted for16.15%(62/384) of cases. Tri-viral mixed infection occurredin4cases and Bi-viral mixed infections occurred in58cases. Sequencinganalyses showed that GII.4, GI, ASV-1, and Ad41genotypes accounted for77.38%(65/84),88.46%(23/26),63.33%(19/30), and94.87%(37/39) of theisolated strains, respectively, which were the predominant epidemic strainsof NV, SV, ASV, and HAdV in the Chongqing region. A total of5NV GIIrecombinant types were identified in this study,27were GII.e/GII.4Sydney2012，1was GII.7/GII.6，1was GII.22/GII.5，12were GII.12/GII.3and3were GII.16/GII.13.Conclusions:1. RV, NV, SV, HAdV and ASV have been found to be the5majorpathogens causing infantile viral diarrhea in Chongqing, responsible73.70%of the total viral diarrhea cases. Among them, RV is the major pathogen,followed by NV. 2. The NV GII.4subtype is the dominant NV epidemic strain, Ad41thedominant HAdV strain, ASV-1the dominant ASV strain, and SV GI.1thedominant SV strain. Mixed infection with various pathogens accounted for16.15%of total infections, and mixed infection including RV is the mostcommon.3. NV-related infections are mostly induced by the NV GII subgroup,with NV GII.4being the predominant genotype. In Chongqing, the firstGII.4Sydney2012strain was isolated in August.4. The NV recombinant in Chongqing region was abundant,afterAugust2012, the NV predominant strains of GII.42006gradually changedto the recombination strains of GII.e/GII.4Sydney2012,and this is the firstreport of the detection of GII.22/GII.5and GII.16/GII.13novelrecombinant norovirus.