Etiological agents distribution and epidemiology of viral diarrhea in children below 5 years old in He′nan province, 2008-2015

Abstract

Objective To investigate the infectious status, etiological spectrum and epidemiological characteristics of rotavirus (group A/B/C), calicivirus (novovirus Ⅰ/Ⅱ, sapovirus), astrovirus and enteric adenovirus in diarrhea cases below 5 years old from 2008 to 2015 in Henan provinces. Methods Totally 2541 stool samples were collected from cases below 5 years old in four sentinel hospitals. All stool specimens were tested for group A rotavirus by double antibody sandwich ELISA method. G/P genotyping of group A rotavirus was determined by nested multiplex PCR. Viral RNA was extracted from all samples and rotavirus (group B/C), calicivirus, astrovirus and enteric adenovirus were detected by two-step reverse transcription-polymerase chain reation (RT-PCR)/PCR. Results One thousand four hundred and twenty-one out of 2 541 samples were positive with a total positive rate of 55.9%, among which, 102 were mixed infection. The isolation rate of rotavirus was 36.0% (914 samples) (group A: 785 cases, group B: 36 cases, group C: 93 cases), calicivirus was 12.1% (308 samples) (novovirus Ⅰ: 64 cases, novovirus Ⅱ: 193 cases, sapovirus: 51 cases), astrovirus was 5.9% (151 samples), enteric adenovirus was 1.9% (48 samples). The group A rotavirus gene type combinations were composed mainly of G9P[8], G2P[4], G3P[8], G1P[8] and most cases were identified from September to November and March to May. Novovirus Ⅱ was predominant in calicivirus and most cases were identifed between March and May. Rotavirus or calicivirus infection was mainly among children aged 4—12 months or 3—5 years, respectively. Clinical manifestations included fever, diarrhea, vomiting, dehydration. Gender and region distributions differed according to the types of pathogen. Conclusions Group A rotavirus and novovirus Ⅱ are the major viral pathogen in diarrhea cases younger than 5 years old in Henan province. Different viral infections exhibit extinct epidemiologic and clinical characteristics. Key words: Diarrhea virus; Infant; Pathogen spectrum; Genotype; Epidemiological feature