Phylogenetic analysis of global hepatitis E virus sequences: genetic diversity, subtypes and zoonosis

Abstract

Nucleotide sequences from a total of 421 HEV isolates were retrieved from Genbank and analysed. Phylogenetically, HEV was classified into four major genotypes. Genotype 1 was more conserved and classified into five subtypes. The number of genotype 2 sequences was limited but can be classified into two subtypes. Genotypes 3 and 4 were extremely diverse and can be subdivided into ten and seven subtypes. Geographically, genotype 1 was isolated from tropical and several subtropical countries in Asia and Africa, and genotype 2 was from Mexico, Nigeria, and Chad; whereas genotype 3 was identified almost worldwide including Asia, Europe, Oceania, North and South America. In contrast, genotype 4 was found exclusively in Asia. It is speculated that genotype 3 originated in the western hemisphere and was imported to several Asian countries such as Japan, Korea and Taiwan, while genotype 4 has been indigenous and likely restricted to Asia. Genotypes 3 and 4 were not only identified in swine but also in wild animals such as boar and a deer. Furthermore, in most areas where genotypes 3 and 4 were characterised, sequences from both humans and animals were highly conserved, indicating they originated from the same infectious sources. Based upon nucleotide differences from five phylogenies, it is proposed that five, two, ten and seven subtypes for HEV genotypes 1, 2, 3 and 4 be designated alphabetised subtypes. Accordingly, a total of 24 subtypes (1a, 1b, 1c, 1d, 1e, 2a, 2b, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 4a, 4b, 4c, 4d, 4e, 4f and 4g) were given.

Frequency of hepatitis E and Hepatitis A virus in water sample collected from Faisalabad, Pakistan

“…HEV isolates are divided into 4 genotypes and more than 24 subtypes [12]. HAV is divided into seven different genotypes (I-VII), which infect human (I-III) and simian (IV-V) [13].…”

Hepatitis-E-Virus

“…Tab. 1) [10][11][12][13][14][15][16][17][18][19][20][21]. Kürzlich wurde in zwei Publikationen vorgeschlagen, die bisher molekular charakterisierten HEV taxonomisch neu einzuordnen [14,15].…”

Hépatite E

“…L'ARN de 7,2 kilobases, coiffé en 5' (7 méthyl guanine) et polyadénylé en 3', comporte trois phases ouvertes de lectures : ORF1, ORF2 et ORF3 (Figure 1). Quatre génotypes (1)(2)(3)(4) Les grandes épidémies se caractérisent par le nombre spectaculaire de sujets infectés (29 000 cas ictériques pour la première épidémie décrite en Inde en 1955). La contamination résulte de l'ingestion d'eau ou d'aliments souillés.…”

“…Libing Zhou, Andre M. Goffinet, Fadel Tissir > La formation des voies axonales préco-ces est une étape essentielle du câblage cérébral [1] ; elle requiert des interactions entre les cônes de croissance et l'environnement et plusieurs facteurs guident les axones dans leur progression, comme des molécules extracellulaires, des cellules jalons [2], ou des interactions de fibre à fibre [3]. Un des carrefours les plus importants, étudié depuis des décennies, est la capsule interne (CI) qui relie le cortex aux autres structures cérébrales, et par laquelle cheminent les fibres originaires du thalamus et destinées au cortex, et les efférences qui quittent le cortex pour gagner diverses cibles sous-corticales dont le thalamus, le tectum, le pont, le bulbe et la moelle.…”