Hiding in Plain Sight? It’s Time to Investigate Other Possible Transmission Routes for Hepatitis E Virus (HEV) in Developed Countries

Abstract

Historically in developed countries, reported hepatitis E cases were typically travellers returning from countries where hepatitis E virus (HEV) is endemic, but now there are increasing numbers of non-travel-related ("autochthonous") cases being reported. Data for HEV in New Zealand remain limited and the transmission routes unproven. We critically reviewed the scientific evidence supporting HEV transmission routes in other developed countries to inform how people in New Zealand may be exposed to this virus. A substantial body of indirect evidence shows domesticated pigs are a source of zoonotic human HEV infection, but there is an information bias towards this established reservoir. The increasing range of animals in which HEV has been detected makes it important to consider other possible animal reservoirs of HEV genotypes that can or could infect humans. Foodborne transmission of HEV from swine and deer products has been proven, and a large body of indirect evidence (e.g. food surveys, epidemiological studies and phylogenetic analyses) support pig products as vehicles of HEV infection. Scarce data from other foods suggest we are neglecting other potential sources of foodborne HEV infection. Moreover, other transmission routes are scarcely investigated in developed countries; the role of infected food handlers, person-to-person transmission via the faecal-oral route, and waterborne transmission from recreational contact or drinking untreated or inadequately treated water. People have become symptomatic after receiving transfusions of HEV-contaminated blood, but it is unclear how important this is in the overall hepatitis E disease burden. There is need for broader research efforts to support establishing risk-based controls.

Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

“…In recent years, the incidence rate of HEV-3 infection has increased in industrialized countries, likely through zoonotic exposure (Van der Poel et al, 2018). Due to the lack of surveillance data, the actual HEV incidences and fatalities per country are often unknown, and therefore the true burden of HEV disease remains unclear (King et al, 2018;Van der Poel et al, 2018).…”

Hepatitis E Virus Infection in the United States: Current Understanding of the Prevalence and Significance in the Liver Transplant Patient Population and Proposed Diagnostic and Treatment Strategies

“…HEV infection has also been transmitted through receipt of blood products. ( 4,7‐9 ) HEV genotypes 5 and 6 have been isolated in Japanese wild boars, and no cases of human infection have been documented. ( 10 ) HEV genotype 7 has been implicated in a case of infection in a man who regularly consumed camel meat and milk.…”

“…Moreover, HEV has been detected in various seafoods, strawberries, and green vegetables, typically due to water contaminated from host animals. ( 4,7‐9 ) One study suggested that there is even a risk of HEV acquisition through growing and consuming one’s own produce. ( 13 ) Post‐LT patients should be counseled on the safe consumption of meat and vegetable products so as to avoid unnecessary exposure to the virus.…”

Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

“…In recent years, the incidence rate of HEV-3 infection has increased in industrialized countries, likely through zoonotic exposure (19). Due to the lack of surveillance data, the actual HEV incidences and fatalities per country are often unknown, and therefore the true burden of HEV disease remains unclear (19, 20).…”