2 ǀ HEV INFECTION IN PIGS
HEV is a zoonotic disease that can be transmitted from animals to
humans. The Orthrohepevirus A affects humans, wild boar, mongoose,
camel, and pigs; Orthrohepevirus B infects chickens; Orthohepevirus C
causes infection in ferrets, rats, shrews, and mink, while
Orthohepevirus D affects bats.37 Studies suggested
that the most important reservoir for HEV genotypes capable of infecting
humans is pigs.38 In 1997, the HEV was identified for
the first time in pigs and pigs are recognized as the main reservoir of
HEV genotypes 3 and 4.39 Several studies have been
conducted on pigs infected with HEV.40-43 However,
anti-HEV antibodies have been isolated from a wide range of species such
as cattle, dogs, goats, deer, donkeys, sheep, and
pigs.37-38,44-45
Exposure to animal feces and consumption of undercooked pork meat can
cause HEV infection. Due to limited data in resource-deficient
countries, Hoan et al.46 evaluated whether pigs could
potentially be a source of HEV infections in Vietnam. Liver samples from
domestic pigs (n = 210) and individuals serum samples exposed to pork
meat and pigs (n = 283) and compared with unexposed controls (n = 168).
In contrast to healthy individuals, persons occupationally acquainted
with pork/pigs meat showed a high seroprevalence. Twenty-six of 210
liver tissues of pig showed HEV-RNA and detected to be HEV genotype 3.
Overall, the results indicate that individuals occupationally exposed to
pork meat and pigs are at associated risk of HEV.
Furthermore, studies showed that
HEV is reportedly associated with the consumption of meat products from
wild boar and pigs.29,47-48 Therefore, in developed
countries cross-species transmission is considered as the major cause of
HEV infection.49-50 Figure 2 shows the transmission of
HEV through a pig.