<FIGURE 1>
The HEV infection is prevalent in Asia and
Africa.18-19 In developing countries, the HEV
infection is responsible for 20-25% of acute hepatitis
cases,18 and in the general population, the mortality
ranges from 0.2 to 1%.15 In Africa, a high prevalence
of HEV infection has been documented recently in animals with HEV
genotypes closer to that of humans and some animals may act as virus
reservoirs suggesting the possibility of zoonotic
transmission.20 In developed countries, the HEV cases
have been increased recently mainly due to the consumption of
undercooked meat, and is a silent threat which need much epidemiological
investigations and appropriate mitigation strategies to be
adopted.18,21-22 In the present scenario, HEV is
considered as an emerging zoonotic infection in many European
countries.23
Autochthonous HEV causes considerable clinical problems in
industrialized countries, where animal species including domestic swine,
wild boar, and wild deer act as reservoirs of HEV-3 and HEV-4 genotypes.
Humans acquire HEV infections by consuming uncooked or undercooked meat
of the infected animals, especially pig livers or sausages made from
infected livers.24 Not much data are available with
regards to HEV prevalence and contamination in food as well sources of
contamination, especially in developing countries, and investigations on
such issues therefore would elucidate a better understanding of
food-borne impact of this important virus and its
maintenance.25
The disease is mainly transmitted via the fecal-oral route by ingestions
of contaminated food and drinking water. HEV contamination of food
sources and surface waters could occur through solid and liquid residues
of infected animals, which act as zoonotic reservoirs. The food-borne
transmission of HEV is mainly due to insufficiently uncooked pig
products, although living in close contact with animals or irrigation
water are the known risk factors of HEV infection in both healthy and
immunocompromised patients.26-28 The HEV may also
transmit via other routes such as zoonotic transmission, mother to
child, and blood transfusion.24,29-34 The transmission
of HEV from person-to-person is infrequent.34-36
The importance of HEV as an important public health issue is rising, and
wide distribution of HEV in humans, animals and environmental as well as
associated zoonotic concerns warrants the strengthening of One Health
concept to tackle HEV. 3,23,25,28-30 This review
discusses the importance of HEV infections and associated risk factors,
with a particular focus on pigs, zoonotic transmissions, environmental
contamination, and water-borne outbreaks.