Analysis of the full-length genome of hepatitis E virus isolates obtained from farm pigs in Mongolia.
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.
Lorenzo
Felipe R
FR
Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi-Ken, Japan.
Tsatsralt-Od
Bira
B
Ganbat
Sanjaa
S
Takahashi
Masaharu
M
Okamoto
Hiroaki
H
D000383:Agriculture; D000818:Animals; D000829:Animals, Domestic / Q000821:virology; D016679:Genome, Viral; D016752:Hepatitis E virus / Q000235:genetics* / Q000302:isolation & purification*; D006524:Hepatitis, Viral, Animal / Q000453:epidemiology / Q000821:virology*; D008969:Molecular Sequence Data; D008986:Mongolia / Q000453:epidemiology; D010802:Phylogeny; D015995:Prevalence; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*; D014766:Viremia