Hepatitis E Virus consists of four recognized major genotypes that infect both humans and other animals. Genotypes 1 and 2 are restricted to humans and often associated with large outbreaks and epidemics in developing countries with poor sanitation conditions, whereas genotypes 3 and 4 infect humans, pigs and other animal species and are responsible for sporadic cases of hepatitis E in both developing and industrialized countries.
Recent reports suggest that other animals such as rats, mongooses, chickens, rabbits, and trout also may harbor Hepatitis E viruses.
. Then, in 2014, research appeared that some Japanse ferrets were also infected with a Hepatitis E Virus, but analysis indicated that these ferret Hepatitis E Virus strains were clearly separated from Dutch strains and should be classified into two distinct clusters suggesting that ferret Hepatitis E Virus is genetically diverse.
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 Aggarwal et al: Hepatitis E in Hepatology – 2011
 Johne et al: Novel hepatitis E virus genotype in Norway rats, Germany in Emerging Infectious Diseases – 2010
 Batts et al: A novel member of the family Hepeviridae from cutthroat trout (Oncorhynchus clarkii) in Virus Research – 2011
 Raj et al: Novel Hepatitis E Virus in Ferrets, the Netherlands in Emerging Infectious Diseases – 2012
 Li et al: Ferret hepatitis E virus infection in Japan in Japanese Journal of Infectious Diseases - 2014