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Order Hepelivirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The Hepelivirales order currently involves 4 families, 6 genera, and 22 species. The order includes first the family Hepeviridae with the genera Piscihepevirus—whose members infect fish—and Orthohepevirus, whose members infect mammals and birds. The hepatitis E virus (HEV) of the Orthohepevirus A species is not only a typical representative of the Orthohepevirus genus but also the most dangerous and the most studied virus of the order. HEV is responsible for self-limiting acute hepatitis in humans and several mammalian species, where the infection may become chronic in immunocompromised individuals. Moreover, the extrahepatic manifestations of Guillain-Barré syndrome, neuralgic amyotrophy, glomerulonephritis, and pancreatitis have been described in humans in a proportion of HEV cases. The Orthohepevirus B species includes avian HEV that causes hepatitis-splenomegaly syndrome in chickens (Purdy et al. 2017).
Hepatitis E Virus
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Kavita Lole, Prudhvi Lal Bhukya, Bangari Haldipur
Previously, HEV was classified under the family Caliciviridae; however, since no similarities exist between nonstructural proteins encoding region of HEV and viruses of this family, HEV was moved to its own family Hepeviridae.16,17 Within the single serotype identified to date, a great genetic diversity between different HEV isolates has been widely reported. Smith et al.18 have proposed a new classification theme for HEV, wherein the family Hepeviridae is divided into two genera, namely, Orthohepevirus and Piscihepevirus. The Orthohepevirus genus is further classified into four species designated as Orthohepevirus A, B, C, and D. Within Orthohepevirus A, four genotypes infecting humans and animals are currently described: HEV-1, HEV-2, HEV-3 and HEV-4. Among these, HEV-1 is a highly conserved genotype and causes large waterborne outbreaks in Asia. HEV-2 is less documented, and a few strains have been isolated from Mexico and Africa (Nigeria). HEV-3 and HEV-4 show a higher genomic diversity,19 infect humans and several animal species, and are main causes of foodborne zoonotic HEV infections.20–22 HEV-3 is associated with sporadic and chronic cases of hepatitis E in humans, mostly in industrialized countries, and is known to infect domestic and wild pigs, deer, mongoose, rabbits, and rats. HEV-4 causes sporadic cases of HE in humans and infects wild and domestic pigs, cattle, and sheep.23,24 In recent years, several new significantly different HEV strains have been identified in animal species like rabbit, ferret, rat, bat, mongoose, camel, and mink. Isolates of HEV strains recovered from wild boars in Japan were grouped into genotypes 5 (HEV-5) and 6 (HEV-6), whereas HEV strains isolated from camels are grouped into genotype 7 (HEV-7). HEV isolates from avian species have been placed in species Orthohepevirus B. Avian HEV shows <50% nucleotide sequence similarities with mammalian HEV strains, but shares common epitopes within capsid proteins with mammalian viruses.25,26 HEV strains isolated from rats, ferrets, and bats are classified into Orthohepevirus C and D.18
Screening, diagnosis and risks associated with Hepatitis E virus infection
Published in Expert Review of Anti-infective Therapy, 2019
Sébastien Lhomme, Florence Legrand-Abravanel, Nassim Kamar, Jacques Izopet
The Orthohepevirus A HEV1 and HEV2 infect humans exclusively and are responsible for waterborne outbreaks of hepatitis in developing countries where sanitary conditions are poor. HEV3 is widely distributed around the world while HEV4 is found mainly in Asia. Both HEV3 and HEV4 are transmitted zoonotically from pigs, wild boar, deer, rabbits and mongooses. Pigs form by far the largest known reservoir and source of HEV contamination. HEV5 and HEV6 have been found in wild boar in Japan but not yet in humans, although cynomolgus monkeys were recently shown to be susceptible to HEV5 [2]. HEV7 has been detected in dromedary camels; it has caused a chronic infection in an immunocompromised patient who consumed camel milk and meat [3,4]. HEV8 has been found in Bactrian camels [4] and Cynomolgus Macaques are susceptible to HEV8 [5].