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Detection And Characterization Of Norovirus And Orthohepadnavirus From Bats

Posted on:2019-02-13Degree:MasterType:Thesis
Country:ChinaCandidate:L E YangFull Text:PDF
GTID:2370330545988251Subject:Prevention of Veterinary Medicine
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Bats are the second most diverse mammals in the world only after rodents,distributed in land other than the earth's poles.Bats are often regarded as the natural hosts of many zoonotic viruses.At present,more than 200 viruses have been found in bats,including some pathogens that have significant public health threats,such as SARS-related coronaviruses,Nipah viruses,Rabies viruses and Marburg viruses and etc.In the southern part of China,the economy is well developed,the climate is suitable and the temperature is moist,it is suitable for the bats survival.At the same time,many new infectious diseases,such as Dengue fever,SARS and Influenza,have been broken out in this place.In order to effectively monitor the new infectious diseases in Fujian and Guangxi areas,and prevent bat virus from cross species and cross-borderspreading to other animals and people,guaranteeing the safety of the people's life,the research on the pathogen ecology of bats carrying viruses in these two areas is of great significance.In this study 758 bats were collected from June 2015 to July 2016,the location of the collection comes from 29 places in 13 cities in Fujian and Guangxi province,the species of bats include two families:Vespertilionidae and Rhinolophidae,totally of 16 species and 5 genus.A total of 14,014,153 reads were obtained by high-throughput sequencing,of which 0.65%(90,449)were annotated to the virus.These viruses are divided into 43 known viral families and 111genera,and including some other unclassified viruses.According to the difference of the host,these viruses-like sequences are divided into mammal virus,insect virus,plant virus and phage.It contains 27viral genera of 18 families of mammal viruses,21 viral genera of 11 families of insect viruses,17 viral genera of 9 families of plant viruses and 30 viral genera of 6 families of phage.Among mammalian viruses,the important virus are Adenoviridae,Papillomaviridae,Picobirnaviridae,Hepadnaviridae,Circoviridae,Retroviridae,Parvoviridae,Astroviridae,Reoviridae,Coronaviridae,Picornaviridae,Flaviviridae,Rhabdoviridae,Anelloviridae,Nairoviridae,Hantaviridae and Caliciviridae etc.By comparing the viruses carried by bats in Fujian and Guangxi,it is found that the viruses carried by bat in Fujian province include 12 genera of 10 mammalian virus families,while the viruses carried by Guangxi bat include 15 mammalian virus families and 38 genera,indicating that the viruses carried by bat in different provinces have regional differences.Among the viruses discovered in metagenomic,norovirus and hepatitis virus have important public health significance,and their diversity and distribution in Fujian and Guangxi are not clear,so the two species of bat viruses were identified by molecular identification in this study.Noroviruses are the second only to the rotaviruses as etiologic agents of acute fulminant gastroenteritis in infants and young children worldwide,with an estimated 200,000 deaths per year in children younger than 5 years of age in developing countries.Currently,the norovirus has been divided into 6 genogroups,GI-GVI,which can infect a variety of mammals,with a distinct genetic diversity.According to the results of virus metagenomic and further RT-PCR screening,results showed that 2 out of 62(3.22%)Rhinolophus affinis collected from Nanping were positive.We amplify the whole genome of virus in one positive sample and obtain the sequence of the full length of 7363nt,analysis of its genome structure,we found that it has a typical structure of the calicivirus,a single strand linear structure,and coding three proteins in the same direction,including polyprotein,VP1 and VP2.The homology analysis showed that it shared the highest nt identity of 73%with the bat NoVBtRs-Ca1V/YN2010 which was identified in Rhinolophus sinicus bat from Yunnan,China.In order to determine its evolutionary relationship,we analysis its genetic evolution by using VP1 gene,compare it with the members of the six other gene groups of the norovirus.The results show that it was placed together with other NoVs,but forming an individual phylogenetic group with BtRs-Ca1V/YN2010,other than 6currently known genogroups,the genetic distance is far away.Accordingly,these bat-borne No Vs can be considered as genogroup VII(GVII).Hepatitis B virus,the prototype emember of the genus Orthohepadnavirus within the family Hepadnaviridae,is one of the most infectious human pathogens,responsible for around 887,000 human deaths annually.In 2013,our laboratory first isolated bat hepatitis virus in long-finger bats,Myanmar,and as a new species included in the ICTV.At present,there are already 4 species of bat hepatitis virus in the Hepadnaviridae,This indicates that HBVs are much more diverse in bats than in other host species.According to the results of virus metagenomic,2 positive samples of bat hepatitis virus were detected from 3 Hipposideros armiger in Hechi,Guangxi.The virus in two positive samples were amplified in full sequence,the total length of the sequence was 3275nt,and the homology between the two samples was 99.8%.It shared the highest nt identity of 96.4%with bat hepadnavirus Longquan-Ha-273 found in Rhinolophus sinicus in Zhejiang,China.The whole genome sequence was used for phylogenetic analysis,according to the results,we found the two sequences in this experiment belong to a new genotype.In this study,we used virus metagenomics to study the virome of bat in Fujian and Guangxi,revealed the diversity and regional differences of virus carried by bats in this area.On this basis,identified a new genogroup of norovirus,and measured the first strain of whole genome sequence of norovirus in the world.In addition,found a new genotype of the bat hepatitis virus,and measured the first strain of whole genome sequence of bat norovirus in the world.In addition,also found a new genotyp of the bats hepatitis virus.This study has important reference value for further revealing the origin and genetic evolution of bat virus and hepatitis virus,and elucidating their public health significance.
Keywords/Search Tags:virus metagenomics, bat, norovirus, orthohepadnavirus, genetic diversity
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