Hepatitis E is a viral hepatitis transmitted by the fecal-oral route. Mortality may be as high as 20% in pregnant women infected during the third trimester. Epidemics of hepatitis E are largely waterborne, occurring in South and Central Asia, tropical East Asia, Africa, and Central America.
CASES/YEAR
100 (US); 20,000,000 (Global)
OTHER NAMES
Enterically transmitted non-A non-B hepatitis; HEV;
INCUBATION
2-9 weeks (average 6 weeks); [CDC Travel]
INITIAL SYMPTOMS
Fever, jaundice, fatigue, anorexia, and abdominal pain; [CDC Travel]
PRECAUTIONS
Standard; Use Contact Precautions for diapered or incontinent persons for the duration of illness. [CDC 2007 Guideline for Isolation Precautions] Period of communicability is not known. [CCDM, p. 271]
COMMENTS
FINDINGS:
The clinical course is similar to hepatitis A. Genotypes 1 and 2 are associated with developing countries: high rates of jaundice and chronic infections not reported. Genotypes 3 and 4 are associated with developed countries: low rates of jaundice and infections may become chronic. [CCDM, p, 270] Most acute liver failure in the tropics is caused by hepatitis viruses (40% by HEV). HBV and HEV are the most common causes of subacute hepatic failure with progressive jaundice, ascites, coagulopathy, renal failure, and encephalopathy. [Guerrant, p. 978] Pregnant women are at risk for liver failure after infection. Immunosuppressed patients (solid organ recipients) may develop chronic infections. [CDC Travel, p. 234]
EPIDEMIOLOGY:
Hepatitis E is transmitted by the fecal-oral route. Mortality may be as high as 20% in pregnant women infected during the third trimester. Natural infections occur in pigs, deer, elk, sheep, cattle, rats, and rabbits. [CCDM, p, 271] Epidemics of hepatitis E are largely waterborne. It is also transmitted by ingestion of raw meat, offal, liver, and shellfish. Figatellu in France (sausage from raw pig liver) and inadequately cooked venison or boar meat are reported causes of infection. [CDC Travel, p. 234]
DIAGNOSTIC
Detecting anti-HEV IgM in serum, but no serological test yet FDA-approved; [CDC Travel, p. 234-5]
SCOPE
Global; Waterborne outbreaks occur in South and Central Asia, tropical East Asia, Africa, and Central America; [CDC Travel]
SIGNS & SYMPTOMS
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>arthralgia
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>fatigue, weakness
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>fever
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>myalgia
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G abdominal pain
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G hepatomegaly
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G jaundice
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G liver function test, abnormal
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G nausea, vomiting
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H leukopenia
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H splenomegaly
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N headache
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S rash (exanthem)
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S urticaria
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*acute renal failure
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*bleeding tendency
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*hepatitis
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*stupor, coma
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*weight loss
SOURCE
Person-to-Person, Human Fecal-Oral, Eating Contaminated Food, Eating Contaminated or Infected Meat, Eating Contaminated Mollusks or Crustacean, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Birds and Poultry, Cattle, Goats and Sheep, Deer, Elk and Antelope, Swine, Human, Wild Animals
TREATMENT
"Among those with chronic HEV infection, case series have reported viral clearance and sustained response in a high proportion of patients with peg-interferon and/or ribavirin." [CCDM, p. 272]
REFERENCES FOR CASES/YEAR
1. (US) Symptomatic cases "extremely rare" in the US; Prevalence of anti-HEV was 21% in 1988-94 NHANES survey. [Harrison ID, p. 888] HEV infection rate in developed countries is controversial. [PPID, p. 2282] Guesstimate: 100 cases/year;
2. (Global) 20 million cases and 57000 deaths every year; [Fact sheets from WHO 2013]