Updates on hepatitis E virus

Abstract

Hepatitis E virus (HEV) is the causative agent of hepatitis E. Globally, it is estimated that 20 million HEV infections with 3.3 million symptomatic cases occur annually, and the mortality rate is 0.5% to 3% in general population.Although hepatitis E is commonly considered as an acute, self-limited disease, HEV infection can be chronic in immunocompromised patients and related with high mortality rate and poor pregnancy outcomes in pregnant women. [1] Characteristics of HEV: HEV is a single-stranded, positive sense RNA virus with genomic length ranging from 6.6 to 7.2 kb with three open reading frames (ORFs): ORF1 encodes non-structural protein associated with HEV RNA replication; ORF2 encodes the capsid protein and a secreted form of ORF2 protein [2] ; and ORF3 encodes a small protein related with the release of HEV. [3] The virus particle is icosahedral and has a diameter of 27 to 32 nm. HEV is non-enveloped in feces and bile but contains a lipid envelope in blood and cell culture supernatant, and hence HEV is declared to be a quasi-enveloped virus. [2] Robust cell culture system for HEV is still lacking, and suitable animal models for HEV include non-human primates, swine, rabbits, and human liver chimeric mice. Given the small size and zoonotic potential for rabbit HEV, rabbits could be an important model in HEV studies.

Hepatitis E Virus (HEV) Synopsis: General Aspects and Focus on Bangladesh

“…The clinical presentation for acute HEV infection is like other acute viral hepatitis, generally asymptomatic (> 90% cases) or mildly symptomatic. During the first week of HEV infection, common symptoms are nausea and vomiting, malaise, fever, and body ache followed by dark-colored urine and jaundice among 5–30% of symptomatic patients; infection is self-limiting usually last <1 month [ 61 , 67 ]. From acute infection with no prior liver disease, progression to acute liver failure (ALF) is rare (~10%).…”

“…Children with hepatomegaly and male patients over 60 years infected with HEV-3 and HEV-4 are susceptible to ALF, and mortality rate is high ~70% manifested with complications such as ascites, encephalopathy, and coagulopathy. Although after acute infection patients develop immunity but re-infection is possible [ 67 ].…”

“…Patients reinfected with HEV usually show a positive result for anti-HEV IgG and HEV RNA but not anti-HEV IgM. Diagnostic algorithm for HEV infection is shown in ( Figure 5 ) [ 3 , 67 ].…”

Nested PCR optimization for detecting hepatitis E virus

“…Globally, an estimated 20 million HEV infections are reported annually, leading to an estimated 3.3 million symptomatic cases of hepatitis E [2]. The HEV is a member of the Hepe-viridae family, which includes the two genera Piscihepevirus and Orthohepevirus [2].…”

“…Globally, an estimated 20 million HEV infections are reported annually, leading to an estimated 3.3 million symptomatic cases of hepatitis E [2]. The HEV is a member of the Hepe-viridae family, which includes the two genera Piscihepevirus and Orthohepevirus [2]. Orthohepeviruses include the four different Orthohepevirus species (A, B, C, D), which may infect a variety of mammalian and avian species.…”