What Family Does Hepatitis E Belong To?

Hepatitis E Virus ( HEV ) belongs to family Hepeviridae . The genome of HEV is a RNA molecule , which is approximately 7.2 kb in size , single - run aground and has positive - sense . Orthohepevirus is a genus of virus specify to the Hepeviridae family . HEV belongs to the genus Orthohepevirus , which consists of four recognized genotypes and at least two putative young genotypes .

Genotype of HEV

Out of four genotypes , 1 and 2 causes large outbreaks of acuate HEV infections in humans . It is coarse in Asia , Mexico and many African nation whereas , genotype 3 and 4 is associated with sporadic , bunch , and continuing lawsuit of HEV in world . It is mostly known to be zoonotic and has been isolate from domestic animals and barbarian animals .

Sequence Homology

Some studies say that HEV can not be class as it shares genome resembles with Caliciviridae , but sequence analysis suggest that it is more closely associated to the Togaviridae family . It remains in the state of transition . However , the most recent statement from the International Committee on Taxonomy of Viruses grouped HEV along with genotype 1 - 4 under Hepeviridae . The new genotype have been assigned to avian HEV , which is recently identified has the virulency to bats and Mustela nigripes .

Avian HEV which is insulate from chickens shares 50 % of its nucleotide sequence with mammalian HEV . Hence , avian HEV plausibly involve a new genus . The newly identified dirty dog HEV shares 59.9 % and 49.9 % succession identities with human and avian HEV whereas , the black-footed ferret HEV shares the highest sequence identity with rat HEV at 72.3 % . The genus Orthohepevirus has late been proposed to cover both the crumb and ferret stress of HEV as well as a novel wild boar HEV pains recovered in Japan that differed from the know Genotypes 1–4 HEV sequestrate by 22.6–27.7 % in nucleotide succession identity . A bat HEV was of late identified from African , Central American , and European bats , and due to high successiveness variegation from fuck HEV isolate at 47 % amino group acid sequence identity , the chiropteran HEV forms a novel phylogenetic clade . The genus Chiropteranhepevirus has been proposed to include all variants of the bat HEV . at last , a strain of HEV was also distinguish in cutthroat trout in the United States with only 13–27 % sequence homology with mammalian or avian hepeviruses leading to a proposal of marriage of another tentative genus , Piscihepevirus , within the Hepeviridae syndicate .

HEV Biology

The genome lie of three open meter reading frames ( ORFs ) , a 5′ non - coding region ( NCR ) , and a 3′ NCR . ORF1 encodes non - structural proteins with economise domain functioning as a methyltransferase , helicase , RNA - dependent RNA polymerase ( RdRp ) , and a papain - like cysteine proteolytic enzyme . In summation , a hypervariable region ( HVR ) within ORF1 may play a role in viral pathogenesis despite being prove to have no influence on the viral infectivity . ORF2 encodes the immunogenic capsid protein , which interact with 3′ viral genomic RNA for encapsidation and contains an endoplasmic reticulum signal peptide and 3′ N - glycosylation sites . ORF3 encodes a small phosphoprotein with incompletely sympathize functions ; however , the tie with cytoskeleton and its necessity for in vivo viral infection in Macaca mulatta macaques suggests that ORF3 plays a purpose in viral replication and assemblage .