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Analysis of the full‐length genome of hepatitis E virus isolates obtained from farm pigs in Mongolia
Author(s) -
Lorenzo Felipe R.,
TsatsraltOd Bira,
Ganbat Sanjaa,
Takahashi Masaharu,
Okamoto Hiroaki
Publication year - 2007
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.20905
Subject(s) - hepatitis e virus , genotype , virology , biology , outbreak , phylogenetic tree , population , hepatitis e , virus , veterinary medicine , genetics , gene , medicine , environmental health
Although no outbreaks of hepatitis E have been reported in Mongolia, a significant proportion of the general population had antibodies to hepatitis E virus (HEV). To investigate whether pigs are possible reservoirs of HEV in Mongolia, serum samples obtained from 243 2‐ or 3‐month‐old pigs on four swine farms surrounding Ulaanbaatar, the capital city of Mongolia, were tested for the presence of anti‐HEV antibodies and HEV RNA. Overall, 223 pigs (91.8%) tested positive for anti‐HEV, while 89 pigs (36.6%) had detectable HEV RNA. The 89 HEV isolates obtained from the viremic pigs were 78.7–100% identical to each other, and 80.9–85.9% similar to the prototype genotype 3 HEV isolate (US1) in the 412‐nucleotide (nt) sequence within open reading frame 2. They were classified into two novel phylogenetic groups within genotype 3, differing by 16.4–21.3%. The swMN06‐A1288 and swMN06‐C1056 isolates, representing each of the two clusters within genotype 3, had a genomic length of nucleotides (nt) 7,222 nt and 7,223 nt, respectively, excluding the poly(A) tail, and shared only 81.6% over the entire genome. Upon comparison with the 25‐reported genotype 3 HEV isolates over the entire genome, swMN06‐A1288 had identities of merely up to 84.9%, while swMN06‐C1056 of only up to 85.9%. Phylogenetic analysis confirmed the remote relatedness of the Mongolian swine isolates to the genotype 3 HEV isolates reported thus far. These results indicate that farm pigs in Mongolia are frequently infected with presumably indigenous HEV strains of genotype 3 and could be a source of HEV infections in humans in Mongolia. J. Med. Virol. 79: 1128–1137, 2007. © 2007 Wiley‐Liss, Inc.