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

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/.