Hepatitis E
Also known as enterically transmitted non-A non-B Hepatitis (ET-NANB), epidemic non-A non-B hepatitis, fecal-oral non-A non-B hepatitis.
Reporting Information
Class B
Report a case, suspected case, and/or positive laboratory result to the local public health department in which the patient resides by the close of the next business day. If patient residence is unknown, report to the local public health department in which the reporting healthcare provider or laboratory is located.
Reporting Form(s) and/or Mechanism
The Ohio Disease Reporting System (ODRS) should be used to report cases and lab findings to the Ohio Department of Health (ODH). For healthcare providers without access to ODRS, the Ohio Confidential Reportable Disease Form (HEA 3334) may be used.
The Positive Laboratory Findings for Reportable Disease Form (HEA 3333) may be used for laboratories without access to ODRS or electronic laboratory reporting (ELR) to report positive results.
The Viral Hepatitis Case Report (CDC OMB 0920-0728) is available for use by the local public health department when following up with cases. Do not send this form to ODH unless otherwise requested; information collected from the form should be entered into ODRS where fields are available.
Key Fields for ODRS Reporting
- Sensitive occupation: direct patient care, child care provider, food handler.
- Sensitive setting: day care or preschool attendee, long term care facility resident.
- Is patient symptomatic.
- Is patient jaundiced.
- All fields in the Epidemiology module.
Agent
Hepatitis E virus (HEV) is a spherical, non-enveloped, single-stranded RNA virus, 32-34 nm in diameter. HEV is classified in the Hepeviridae family.
Note: Hepatitis A, hepatitis B and hepatitis C are each reportable as individual entities (see Hepatitis A, Hepatitis B, and Hepatitis C IDCM chapters). Hepatitis D occurs only in association with hepatitis B. Other viruses (e.g., cytomegalovirus and Epstein-Barr virus) can cause hepatitis or abnormally elevated liver enzymes. Hepatitis E is the cause of non-A, non-B, non-C hepatitis that will be discussed here.
Case Definition
The Centers for Disease Control and Prevention (CDC) has not established a clinical case definition, laboratory criteria for diagnosis, or case classification for hepatitis E. Diagnosis of hepatitis E based on clinical signs and laboratory criteria are included in the Ohio case definition below.
Clinical Criteria
An illness with:
- Discrete onset of symptoms and
- Jaundice, dark urine, or elevated serum aminotransferase levels (ALT) >200 IU/L.
Laboratory Criteria for Diagnosis
- IgM anti-HAV negative and
- IgM anti-HBc negative (if done) or HBsAg negative and
- Antibody to hepatitis C virus (anti-HCV) negative (if done) and
- IgM anti-HEV positive.
Case Classification
Confirmed
A case that meets the clinical case definition and the laboratory criteria for diagnosis.
Signs and Symptoms
Hepatitis E commonly presents with abdominal pain, anorexia, dark urine, pale stools, fever, fatigue, hepatomegaly, jaundice, malaise, nausea, and emesis. Less frequent symptoms include arthralgia, diarrhea, pruritus, and urticaria. The ratio of symptomatic to asymptomatic infection in outbreak settings is reported to range from 1:2 to 1:13. Fulminant disease is rare, except in pregnant women.
Chronic hepatitis E infection is rare and has only been reported in organ transplant patients and people with severe immunodeficiency.
The case fatality rate overall is 1-3%, except in pregnant women where it may reach 10-25% among those infected during the third trimester.
Diagnosis
Hepatitis E is a diagnosis of exclusion. Diagnosis depends on clinical and epidemiologic features, as well as exclusion of other etiologies of hepatitis, especially hepatitis A, by serologic laboratory tests. Hepatitis E is characterized by symptoms indicative of liver inflammation, with a negative history of exposure to toxic substances, and the laboratory profile noted in the Case Definition above.
Diagnostic tests available include: enzyme immunoassays (EIAs) and Western blot assays to detect IgM and IgG anti-HEV in serum, polymerase chain reaction (PCR) tests to detect HEV RNA in serum and stool, immunofluorescent antibody blocking assays to detect antibody to HEV antigen in serum and liver, and immune electron microscopy to visualize viral particles in feces.
Epidemiology
Source
Humans are the natural host for HEV. The occurrence of sporadic cases may maintain transmission during interepidemic periods, but a nonhuman reservoir for HEV is also possible.
Non-human primates (e.g., chimpanzees, cynomolgus monkeys, rhesus monkeys, pig-tail monkeys, owl monkeys, tamarins, African green monkeys) are susceptible to natural infection with humans HEV strains. Pigs, chicken and cattle have been found to have natural HEV infections, especially in highly endemic areas.
Occurrence
Hepatitis E outbreaks have occurred over a wide geographic area, primarily in developing countries with inadequate sanitation. It has occurred in epidemics or sporadically in parts of Asia, Africa, and Mexico. Outbreaks often manifest as waterborne epidemics, but sporadic cases and outbreaks not related to water have occurred.
The attack rate is highest in young adults, with cases uncommon in children and the elderly.
In the United States and other industrialized countries, hepatitis E has been diagnosed primarily among travelers returning from HEV-endemic countries.
In the United States and other nonendemic areas where outbreaks of hepatitis E have not been documented, a low prevalence of anti-HEV (<2%) has been found in healthy populations. The source of infection for these persons is unknown.
Mode of Transmission
HEV is transmitted primarily by the fecal-oral route, with contaminated water the most commonly documented vehicle of transmission. Person-to-person transmission of HEV appears to be uncommon; however, nosocomial transmission, presumably by person-to-person contact, has been reported to occur.
Recent studies suggest that hepatitis E may be a zoonotic disease in areas with concurrent human infection. In developed countries, sporadic outbreaks have occurred following consumption of uncooked/undercooked pork or deer meat.
Period of Communicability
The period of infectivity of hepatitis E following acute infection has not been determined, but virus excretion in stool has been demonstrated up to 14 days after onset of illness.
Incubation Period
From 15-64 days, with a mean incubation period of 26-42 days.
Public Health Management
Case
Treatment
No therapeutic measures have been proven effective following the onset of disease. Diet and rest should be dictated by the individual's sense of well-being.
Isolation
None.
Contacts
Immune globulin (IG) prepared from plasma collected in non-HEV endemic areas is not effective in preventing clinical disease during hepatitis E outbreaks. The efficacy of IG prepared from plasma collected in HEV endemic areas is unclear.
Prevention and Control
Prevention of hepatitis E relies primarily upon the provision of clean water supplies. Educational programs should be designed to stress sanitary disposal of feces and careful handwashing after defecation and before handling food.
Vaccination
A recombinant hepatitis E vaccine using recombinant capsid protein was evaluated in a phase III clinical trial and was demonstrated to be effective in preventing disease, but is not available outside the research setting. No FDA-approved vaccine for Hepatitis E is currently available in the United States.
Prophylaxis
There is no evidence that IG manufactured in the United States or Europe will prevent infection.
Travelers
Travelers to endemic areas should take precautions to avoid contaminated food and water, including avoidance of drinking water, beverages with ice of unknown purity, and eating uncooked shellfish and uncooked fruits or vegetables not peeled or prepared by the traveler.