Hepatitis E
Hepatitis E virus is a herpevirus and an RNA virus. It causes acute viral hepatitis.
There are four genotypes. Types 1 and 2 are mostly found in the tropics and subtropics and cannot cause chronic hepatitis. They only infect humans.
Types 3 and 4 are found in animal reservoirs and can cause chronic hepatitis. These types are mostly present in Western countries.
Etiology
Like hepatitis A, transmission is faecal-oral.
Transmission of types 1 and 2 usually occurs due to:
- Contaminated food or water
- Close personal contact
- IV drug users
- Blood exposure (rare)
Transmission of types 3 and 4 usually occurs with direct contact of or consumption of infected animals, so they’re zoonotic infections.
Clinical features
HEV causes self-limited acute hepatitis. The clinical features of HEV are similar to those of HAV, with one important exception. Subtypes 1 and 2 infection has a high mortality rate in pregnant women, around 25%.
Subtypes 3 and 4 can progress to chronic hepatitis, whereas subtypes 1 and 2 can’t. Subtype 3 has special extrahepatic manifestations, including neurological problems (neuralgic amyotrophy and GBS), glomerulonephritis, and pancreatitis.
Diagnosis and evaluation
Typical laboratory features of hepatitis can be present.
Diagnosis is based on serology. IgM anti-HEV shows acute infection while IgG anti-HEV shows immunity to HEV, either due to past infection or vaccination.
Treatment
Acute hepatitis E is self-limiting and does not require treatment.
Chronic hepatitis E requires treatment. In case of an immunosuppressed patients, reducing the intensity of the immunosuppressive treatment may cure the chronic hepatitis. In other cases, a 3 month course of ribavirin is used.
Prevention
There is a vaccine for hepatitis E called Hecolin, but it is not generally available. It's only lisenced in China. Hygiene and food safety is important.