Investigation Of Viral Infection Among Children With Diarrhea And Detection Of Enteric Virus In Sewerage

Objective:As a common health problem, diarrheal disease is still the most important causes of global mortality and morbidity in infant and children. Viruses have been regarded as the major cause of diarrheal illnesses among children under five years of age. There are many viral agents among the sewerage. Important waterborne pathogenic viruses include many enteric viruses that are transmitted via the fecal-oral route. Viruses were obtained from sewage samples and the stools of children to determine the prevalence and the molecular characterization of enteric viral infection among diarrheic children and sewage in Tianjin.Methods:We collected stool specimens from April 2008 to April 2009 from patients hospitalized in Tianjin Children's Hospital, and investigated the prevalence of major viral etiologic agents and their molecular characteristics by using a combination of ELISA , cell culture, (RT-)PCR techniques and sequencing, as well as describe the epidemiological characteristics of the hospitalized children (i.e., age, sex, address, presence of dehydration, duration of hospitalization, and clinical symptoms) and their relationship to the different viral infections were evaluated. SPSS was employed for statistical analysis on the collected data.The membrane adsorption-elution method combine with PEG and the calcium flocculation-citrate dissolution method combine with ultrafiltration were used to concentrate virus from sewage water. The viruses were detected by means of(RT-)PCR then sequencing for the genotype.Results:A total of 921 stool specimens were collected and detected for rotavirus (RV) and Human adenovirus (HAdV) using immunological methods from April 2008 to April 2009 from children hospitalized in Tianjin Children's Hospital for acute diarrhea. Of these, 766 stool specimens were detected for Human Adenoviruses (HAdV), Human Caliciviruses (HucV) by (RT-) PCR. The positive-virus(except for HucV)were identified by cell culture and (RT-) PCR. All the PCR-positive products were sequenced.In this study we found that 46.48% of the cases among under fives in Tianjin is at least due to one of the four major viruses that causing diarrhea in children. From April 2008 to April 2009, RV was detected in 28.56 %( 263/921) of the cases, HAdV 17.62 %(135/766), NoV 5.87 %(45/766) and HAstV 3.15% (29/921) respectively. A high mixed infections founed 8.09%(62/766) of all cases, the most frequent mixed infections was RV-HAdV with 34(54.85%), and then was RV-NoV with 11 (17.74%). HAdV -NoV were detected in 11.29% (7 out of 62 cases) of the mixed infections, RV -HAstV in 8.06% (5 out of 62 cases), and HAdV and HAstV in 4.84% (3 out of 62 cases).No NoV combined HAstV were found. There are two cases included three viral infections, RV+HAdV+NoV and RV+HAdV+HAstV. The G1 genotype were the predominant strains (41/54,75.93%) of RV, followed by G3 strain (11/54,20.37%), but G2 and G9 strain were both found only 1 case(1/54,1.85%). The most frequent HAdV type was Ad41(26/30,86.67%), then followed by Ad1(4/30,13.33%). There was no Ad40 serotype found. It showed a clear predominance of HucV all belonging to the NoV genotype 2 strain, of these, 25 NoV cases (25/31,80.65%) were GII-4/2006b and 6 NoV case (6/31,19.35%) was GII-3. All of HAstV were HAstV-1.356 viral agents-positive patients including 119 girls (33.43%) and 237 boys (66.57%) but a similar detection rate(42.35%Vs48.87%) between sexes, and the median ages were 7 months (range, 1 hour to 60 months).Children aged less than 2 years are the most susceptible population to viral diarrhea. The median ages being found in NoV-infected patients were older than non-NoV infections. The viruses detection rate in rural area were similar to urban area, and no difference between them.Vomiting and dehydration were more frequent among patients with mixed viral infection. NoV and RV infections have a higher dehydration rate than other viral infections. HAstV infections have a longer duration of hospitalization. The types of stool were most of watery stool and no significant difference in different viral infections or non-virus infections.Most viral infections were usually found in quarter one and four while HAdV infection peaking was in quarter one and three.One samples of secondary effluent yielded HAV in quarter four. PV1 were detected and sequenced in two samples in quarter one and four. Only one samples was RV-positive(G6) that in quarter four. Conclusions:This study provided the complete and comparable etiological and epidemiological information of acute viral diarrhea in hospitalized children in Tianjin. In this study, RV was the leading cause of diarrheal disease in infants and children followed by HAdV, NoV and HAstV. Mixed viral infection play a important role in children diarrhea.Viruses were existed in secondary effluent.This results suggest that virus in secondary effluent may contaminate surface water and will harm to human.