H E P T I T I S E

V I R U S

VIRION:Non-enveloped, spherical, 32-34 nm in diameter. RNA genome is enclosed within a capsid composed of 60 capsid proteins, assembled into T=1 isometric icosahedral particle.

Hepatitis E Virus (Hepeviridae family)

GENOME:Monopartite, linear, ssRNA(+) genome . The 5’ end is capped and the 3’ terminus is polyadenylated.

GENE EXPRESSION:ORF1 encodes nonstructural proteins; ORF2 encodes capsid protein; ORF3 encodes small immunogenic protein.

TRANSMISSIONBy Oral,Fecal route. Zoonotic & Fomite.

Host : Human, pig, monkey,

some rodents,& chicken.

INFECTION :

Primary site : possibly the intestinal tract.

Secondary site : hepatocytes & possibly cells in biliary tract.

Treatment of chronic hepatitis E

Treatment options for chronic hepatitis include: The first step in the treatment is reduction of immuno supression medication in 16 solid organ transplant

recipients with chronic hepatitis E ,led to clearance of HEV in 4 cases (25%) . A second possible treatment option is administration of pegylated -interferon α with ribavirin. Treatment durations varied between 3 and 12 months. Ribavirin has also been used in a not -transplanted patient with severe acute hepatitis E who showed rapid

improvement of symptoms and liver function tests during treatment .

VACCINATION OF HEVNo commercial HEV vaccine is currently available. A vaccine developed by GSK & the Walter Reed Army Institute that was successfully tested in a Phase II study (Shrestha 2007). However, this vaccine has not been further developed.

A group from China reported data recently from a very large successful Phase III vaccine trial (Zhu 2010) . This trial included almost 110,000 individuals who received either a recombinant HEV vaccine (“HEV 239”) or placebo. The vaccine efficacy after 3 doses was 100%. Moreover, the efficacy of this vaccine needs to be evaluated in special risks groups such as patients with end-stage liver disease or immuno suppressed individuals. It is also unknown if HEV -239 also protects from HEV genotype 3 infection (Wedemeyer and Pischke 2011)