The Journal of Viral Hepatitis has published a review of the clinical manifestations of chronic hepatitis E virus (HEV), including a discussion of the factors determining persistence and chronicity.
HEV is commonly described as an acute, self-limiting hepatitis. This is particularly true of HEV genotypes 1 and 2, which are human pathogens. However, the zoonotic genotype HEV 3 has been increasingly reported as a cause of chronic hepatitis (defined as detectable HEV RNA in stool or serum 3-6 months after infection) and occurs almost exclusively in patients who are immunocompromised. Although commonly asymptomatic, chronic HEV infection has been associated with rapidly progressing liver disease and extrahepatic manifestations including neurologic disorders.
Groups of people with immunocompromise identified as having chronic HEV include individuals who have undergone solid organ transplant, those receiving chemotherapy for hematologic malignancies, and those with HIV.
Although the exact mechanism for progression from acute to chronic infection is still unknown, several factors appear to be involved in the persistence of HEV. These include greater HEV quasispecies diversity and impaired innate and adaptive immune responses. It is unclear how HEV genotype or epidemiologic differences among infections with these genotypes affect the progression of infection or the risk for chronic HEV.
Investigators recommended that future research be focused on “the epidemiology of chronic HEV infection and delineating the mechanisms that aid HEV persistence.”
Narayanan S, Abutaleb A, Sherman KE, Kottilil S. Clinical features and determinants of chronicity in hepatitis E virus infection [published online January 12, 2019]. J Viral Hepat. doi: 10.1111/jvh.13059