Hepatitis E Virus Infection Among Patients With Acute Non-A, Non-B, Non-C Hepatitis in Al-Rajhy University Hospital for Liver

Hepatitis E is the fifth known human viral hepatitis and is probably the most common cause of acute viral hepatitis in the world. The incidence of acute hepatitis E is estimated at 3 million human cases per year worldwide, with around 70,000 deaths. Most cases occur in endemic countries, but the number of cases in low-endemic areas has increased. HEV seroprevalence is high in developing countries, such as India and Southeast Asia, ranging from 27-80%. Acute disease mortality is 1-4%, with risk being higher in pregnant women and immunodeficient patients.

The four more prevalent genotypes are allocated into two groups. Epidemic hepatitis E includes genotypes 1 and 2, which are considered human viruses and have caused the epidemics of hepatitis. These forms are transmitted mainly by contaminated water and the fecal-oral route. endemic hepatitis E includes genotypes 3 and 4, which are considered swine viruses (common in domestic and wild pigs), capable of infecting humans as an accidental host and therefore considered zoonotics.

The course and clinical presentation of hepatitis E is highly variable. The detailed mechanisms that lead to the different clinical outcomes in hepatitis E are only partially understood. It is known that both viral factors (genotype and dose of inoculum) and host factors (presence of previous liver disease, pregnancy and distinct genetic polymorphisms) determine the course of infection. In most cases, hepatitis E causes self-limited illness, lasting from a few days to weeks, with an average of 4-6 weeks. However, in developed countries it can cause chronic disease with rapid progression to cirrhosis, especially in patients who are transplanted, have hematological malignancies requiring chemotherapy, or have infection with HIV.

Hepatitis E is an underdiagnosed disease, partly due to the use of serological tests with low sensitivity. Diagnosis can be made indirectly by detecting antibodies against HEV in the serum, or directly by detecting the genome of the virus in blood or other body fluids. The tests for anti-hepatitis E antibody screening are commercially available, but none of them has been approved by the Food and Drug Administration (FDA). Unfortunately, the sensitivity and specificity of these tests vary greatly and this could explain the discrepancies in rates of anti-hepatitis E antibodies published for the various populations studied. The tests for viral RNA in serum and feces are confirmatory, but still experimental.