Knowledge gaps and research priorities in the prevention and control of hepatitis E virus infection

Abstract

Hepatitis E virus (HEV), family Hepeviridae, is a main cause of epidemic hepatitis in developing countries and sporadic and cluster cases of hepatitis in industrialized countries. There are an increasing number of reported cases in humans especially in industrialized countries, and there is a high potential for transboundary spread of zoonotic genotypes of the virus through the transport of pigs, pig products and by-products. Bloodborne transmission of the virus has been reported with a significant medical concern. To better coordinate HEV research and design better control measures of HEV infections in animals, a group of HEV experts reviewed the current knowledge on the disease and considered the existing disease control tools. It was concluded that there is a lack of in-depth information about the spread of the virus from pigs to humans. The role of animals other than pigs in the zoonotic transmission of the virus to humans and the extent of foodborne transmission are poorly understood. Factors involved in development of clinical disease such as infectious dose, susceptibility and virulence of virus strains need to be studied more extensively. However, such studies are greatly hindered by the absence of a broadly applicable, efficient and sensitive in vitro cell culture system for HEV. Diagnostic tools for HEV are available but need to be further validated, harmonized and standardized. Commercially available HEV vaccines for the control of HEV infection in animal populations are needed as such vaccines can minimize the zoonotic risk for humans. Anti-HEV drugs for treatment of HEV-infected patients need to be studied more extensively. The detailed expert review can be downloaded from the project website at http://www.discontools.eu/.

Viability RT-qPCR to Distinguish Between HEV and HAV With Intact and Altered Capsids

“…Although some laboratories have successfully cultivated HEV in cell culture (Van der Poel et al, 2018), there are limitations that need to be overcome before these methods can routinely be used. In the meantime, evaluation of the thermal inactivation of HEV has been performed using animal models, HEV surrogates and capsid integrity assays (Cook et al, 2017; Van der Poel et al, 2018).…”

“…In the meantime, evaluation of the thermal inactivation of HEV has been performed using animal models, HEV surrogates and capsid integrity assays (Cook et al, 2017; Van der Poel et al, 2018). …”

“…Molecular methods, particularly real-time reverse transcriptase polymerase chain reaction (RT-qPCR), have demonstrated high sensitivity, specificity, and ability to deliver reliable quantitative data in food and environmental samples (Martin-Latil et al, 2014, 2016; Di Bartolo et al, 2015; Mesquita et al, 2016), although such results do not indicate at the infectivity of detected viruses. In addition, alternative strategies to directly study infectivity such as cell culture systems and animal models do not seem to be reliable or practical yet (Ricci et al, 2017; Van der Poel et al, 2018), although promising results have been reported (Emerson et al, 2005; Johne et al, 2016; Imagawa et al, 2018). To enable the differentiation between infectious and inactivated viral particles, different approaches based on capsid integrity have been reported:…”

“…Similarly, long-template PCR assays decrease the amplification efficiency limiting its use especially for food-related application with expected low contamination levels (Wolf et al, 2009). Moreover, selective recovery of potentially infectious HEV particles by a binding approach cannot be developed because the specific receptors are not clearly defined (Van der Poel et al, 2018). …”

HEVnet: a One Health, collaborative, interdisciplinary network and sequence data repository for enhanced hepatitis E virus molecular typing, characterisation and epidemiological investigations

“…Collaboration across disciplines is also crucial for the implementation of prevention and control measures that benefit public health, as HEV does not cause disease in animals and is therefore not considered a relevant veterinary issue requiring animal disease-control measures [9,10]. …”