Division of Viral Hepatitis Epidemiology and Prevention of Viral Hepatitis A to E: Hepatitis E Virus [SLIDE 1] Title Slide This slide set presents an overview of the clinical and epidemiologic features for viral hepatitis A, B, C, D, and E and prevention measures for these infections. More detailed information regarding the epidemiologic features and prevention measures can be found on-line at http://www.cdc.gov/MMWR/MMWR.html: for hepatitis A read the MMWR, Prevention of Hepatitis A Through Active or Passive Immunization: Recommendations of the Advisory Committee on Immunization Practices, Vol. 48, No RR12;1, 10/01/1999; for hepatitis B read the MMWR, Recommendations to Prevent Hepatitis B Virus Transmission – US, Vol.44, No 30;574, 08/04/1995, Updated; for hepatitis C read the MMWR, Recommendations for Prevention and Control of Hepatitis C Virus (HCV) Infection and HCV-Related Chronic Disease, Vol. 47, No RR19;1, 10/16/1998. Division of Viral Hepatitis

Geographic Distribution of Hepatitis E Outbreaks or Confirmed Infection in > 25% of Sporadic Non-ABC Hepatitis [SLIDE 76] Geographic Distribution of Hepatitis E* Outbreaks of hepatitis E have occurred over a wide geographic area, primarily in developing countries with inadequate environmental sanitation. The reservoir of HEV in these areas is unknown. The occurrence of sporadic HEV infections in humans may maintain transmission during interepidemic periods, but a nonhuman reservoir for HEV is also possible. In the United States and other nonendemic areas, where outbreaks of hepatitis E have not been documented to occur, a low prevalence of anti‑HEV (<2%) has been found in healthy populations. The source of infection for these persons is unknown. * (Note: The map of HEV infection generalizes available data and patterns may vary within countries.)

Epidemiologic Features Hepatitis E – Epidemiologic Features Most outbreaks associated with fecally contaminated drinking water Minimal person-to-person transmission U.S. cases usually have history of travel to HEV-endemic areas 29 29 29

Incubation period: Average 40 days Range 15-60 days Hepatitis E – Clinical Features Incubation period: Average 40 days Range 15-60 days Case-fatality rate: Overall, 1%-3% Pregnant women, 15%-25% Illness severity: Increased with age Chronic sequelae: None identified [SLIDE 73] Hepatitis E: Clinical Features The incubation period following exposure to HEV ranges from 15 to 60 days (mean, 40 days). Typical clinical signs and symptoms of acute hepatitis E are similar to those of other types of viral hepatitis and include abdominal pain anorexia, dark urine, fever, hepatomegaly, jaundice, malaise, nausea, and vomiting. Other less common symptoms include arthralgia, diarrhea, pruritus, and urticarial rash. The period of infectivity following acute infection has not been determined but virus excretion in stools has been demonstrated up to 14 days after illness onset. In most hepatitis E outbreaks, the highest rates of clinically evident disease have been in young to middle‑age adults; lower disease rates in younger age groups may be the result of anicteric and/or subclinical HEV infection. No evidence of chronic infection has been detected in long‑term follow‑up of patients with hepatitis E.

Hepatitis E Virus Infection Typical Serological Course IgG anti-HEV Titer Symptoms ALT IgM anti-HEV Virus in stool 1 2 3 4 5 6 7 8 9 10 11 12 13 Weeks after Exposure [SLIDE 74] Hepatitis E Virus Infection: Typical Serologic Course The typical serologic course following HEV infection has been characterized using experimental models of infection in nonhuman primates and human volunteer studies. In two human volunteer studies, liver enzyme elevations occurred 4‑5 weeks after oral ingestion and persisted for 20‑90 days. Virus excretion in stools occurred approximately 4 weeks after oral ingestion and persisted for about 2 weeks. Both IgM and IgG antibody to HEV (anti‑HEV) are elicited following HEV infection. The titer of IgM anti‑HEV declines rapidly during early convalescence; IgG anti‑HEV persists and appears to provide at least short‑term protection against disease. No serologic tests to diagnose HEV infection are commercially available in the United States. However, several diagnostic tests are available in research laboratories, including enzyme immunoassays and Western blot assays to detect IgM and IgG anti‑HEV in serum, polymerase chain reaction tests to detect HEV RNA in serum and stool, and immunofluorescent antibody blocking assays to detect antibody to HEV antigen in serum and liver.

Prevention and Control Measures for Travelers to HEV – Endemic Regions Avoid drinking water (and beverages with ice) of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveler IG prepared from donors in Western countries does not prevent infection Unknown efficacy of IG prepared from donors in endemic areas Future vaccine (?) 31 31 31

CDC – Educational and Training Resources Website: www.cdc.gov/hepatitis Toll-free information: 888-4HEPCDC (888-443-7232) Web-based HCV training for professionals (http://www.cdc.gov/ncidod/diseases/hepatitis/training/index.htm) Brochures, posters, slide sets, videos (http://www.cdc.gov/ncidod/diseases/hepatitis/resource/index.htm)