Hepatitis E virus - Transmission, Pathogenesis, Host immunity, Syndromes, Lab diagnosis, Treatment

Transmission of Hepatitis E virus

Hepatitis E virus transmission mostly occurs via the fecal-oral route, rarely by blood products.

Pathogenesis of Hepatitis E virus

The incubation period of the Hepatitis E virus is of 2-9 weeks with an average of 35 days. The infection is usually, a self-limiting disease that is similar to HAV.

After a short prodromal phase with fatigue and nausea preceded the icteric phase that includes jaundice. In immunocompromised patients (organ transplant recipients), Hepatitis E virus may cause chronic infections.

The Hepatitis E virus infection may cause liver fibrosis and cirrhosis (fatality- 1.3%), encephalopathy, and disseminated intravascular coagulation. Serious infection in pregnant women, especially in the last trimester of pregnancy (fatality rate 15-20%) may cause fulminant hepatic failure (rate high).

Host immunity of Hepatitis E virus

IgM Ab appears first which falls rapidly after infection and becomes undetectable within 6 months. Anti Hepatitis E virus IgG presents longer than 6 months and provides protection from reinfection.

Clinical syndromes of Hepatitis E virus

The clinical syndromes of Hepatitis E virus includes:

1. Liver fibrosis and cirrhosis

2. encephalopathy, disseminated intravascular coagulation

3. fulminant hepatic failure in pregnant women (rate high)

4. pathological findings include:

• infiltration of the portal tract by lymphocytes and polymorphonuclear leukocytes

• balloon hepatocytes

• formation of acidophilic bodies

• intralobular necrosis of hepatocytes

Lab diagnosis of Hepatitis E virus

The laboratory diagnosis of the Hepatitis E virus is done after the collection of the specimen/sample.

Specimen

• Stool

• Blood

(not yet cultured)

Serodiagnosis

Serodiagnosis, a commonly used test for Hepatitis E virus infection includes the detection of IgM and IgG anti-HEV antibodies and detection of Hepatitis E virus RNA

• Western blot and EIA using antigenic domains from ORF2 and ORF3 are done for serodiagnosis

• detection of anti-HEV IgM and IgG helps to differentiate acute and chronic infections

Molecular diagnosis

A molecular diagnosis such as PCR detects Hepatitis E virus RNA in blood, and serum.

Treatment of Hepatitis E virus

Treatment of Hepatitis E virus infection are done:

• no vaccines are available; supportive therapy offered

• 1^st step of treatment- reduction of immunosuppression medication

• 2^nd step of treatment- administration of pegylated interferon α with ribavirin

• treatment duration varies