hepatitis e infection
DESCRIPTION
Hepatitis E infectionTRANSCRIPT
DR.T.V.RAO MD 1
Dr.T.V.Rao MD
HEPATITIS E INFECTION
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WHAT IS VIRAL HEPATITIS E• Hepatitis E is a viral hepatitis caused by
infection with a virus called hepatitis E virus (HEV). HEV is a positive-sense single-stranded RNA icosahedral virus with a 7.5 kilobase genome. HEV has a fecal-oral transmission route. It is one of five known hepatitis viruses: A, B, C, D, and E. Infection with this virus was first documented in 1955 during an outbreak in New Delhi, India
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A TRUE STORY OF HEPATITIS E INFECTION
• In 1983, Dr. Balayan was investigating an outbreak of non-A, non-B hepatitis in a central Asian part of the Soviet Union. Though he wanted to bring samples back to his Moscow laboratory, he lacked refrigeration. So he made a shake of yogurt and an infected patient’s stool, drank it, went back to Moscow, and waited. When he became seriously ill a few weeks later, he started collecting and analysing his own samples. In these he found a new virus that produced liver injury in laboratory animals and could be seen by electron microscopy. It looked a lot like hepatitis A virus, but he could show that it was not, because he already had antibodies against the hepatitis A virus and these did not react with the new virus.
• ( National Institute of Allergy and Infectious Diseases )
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ROBERT PURCELL, ALBERT KAPIKIAN, AND STEPHEN FEINSTONE WITH AN ELECTRON MICROSCOPE. (CREDIT: NIAID)
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HEPATITIS E - GENOME• The genome is approximately 7200 bases in length, is a
polyadenylated single-strand RNA molecule that contains three discontinuous and partially overlapping open reading frames (ORFs) along with 5' and 3' cis-acting elements, which have important roles in HEV replication and transcription. ORF1 encode a methyltransferase, protease, helicase and replicase; ORF2 encode the capsid protein and ORF3 encodes a protein of undefined function. A three-dimensional, atomic-resolution structure of the capsid protein in the context of a virus-like particle has been described. An in vitro culture system is not yet available
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Incubation period: Average 40 daysRange 15-60
days Case-fatality rate: Overall, 1%-3%
Pregnant women, 15%-25%
Illness severity: Increased with age Chronic sequelae: None identified
Hepatitis E - Clinical Features
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Most outbreaks associated with faecally contaminated drinking water.
Several other large epidemics have occurred since in the Indian subcontinent and the USSR, China, Africa and Mexico.
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.
Minimal person-to-person transmission.
Hepatitis E Epidemiologic Features
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GEOGRAPHICAL DISTRIBUTION• Hepatitis E is found worldwide and different
genotypes of the hepatitis E virus determine differences in epidemiology. For example, genotype 1 is usually seen in developing countries and causes community level outbreaks while genotype 3 is usually seen in the developed countries and does not cause outbreaks
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DISTRIBUTION OF HEPATITIS E INFECTION, 2010
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• Globally, 70 000 deaths and 3.4 million cases of acute hepatitis E are attributable to infection with hepatitis E virus genotypes 1 and 2.
MORBIDITY AND MORTALITY
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• The hepatitis E virus is transmitted mainly through the faecal-oral route due to faecal contamination of drinking water. Other transmission routes have been identified, which include
TRANSMISSION OF INFECTION
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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.
Vaccine?
Prevention and Control
Measures for Travelers to HEV-Endemic Regions
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TRANSMISSION
• Foodborne transmission from ingestion of products derived from infected animals;
• Zoonotic transmission from animals to humans;
• Transfusion of infected blood products;
• Vertical transmission from a pregnant woman to her foetus.
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INCUBATION PERIOD• The incubation period following
exposure to the hepatitis E virus ranges from three to eight weeks, with a mean of 40 days. The period of communicability is unknown.
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SYMPTOMS• The hepatitis E virus causes acute sporadic
and epidemic viral hepatitis. Symptomatic infection is most common in young adults aged 15–40 years. Although infection is frequent in children, the disease is mostly asymptomatic or causes a very mild illness without jaundice (anicteric) that goes undiagnosed
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CLINICAL PRESENTATIONJaundice • anorexia (loss of appetite);• an enlarged, tender liver (hepatomegaly);• abdominal pain and tenderness;• nausea and vomiting;• fever.
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HEPATITIS E INFECTION AND PREGNANCY
• In rare cases, acute hepatitis E can result in fulminant hepatitis (acute liver failure) and death. Overall population mortality rates from hepatitis E range from 0.5% to 4.0%. Fulminant hepatitis occurs more frequently during pregnancy. Pregnant women are at greater risk of obstetrical complications and mortality from hepatitis E, which can induce a mortality rate of 20% among pregnant women in their third trimester.
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• Cases of chronic hepatitis E infection have been reported in immunosuppressed people. Reactivation of hepatitis E infection has also been reported in immunocompromised people.
CHRONIC HEPATITIS E INFECTION
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• Diagnosis of hepatitis E infection is therefore usually based on the detection of specific antibodies to the virus in the blood.
DIAGNOSIS BY DETECTION OF ANTIBODIES
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• Reverse transcriptase polymerase chain reaction (RT-PCR) to detect the hepatitis E virus RNA;
• Immune electron microscopy to detect the hepatitis E virus.
NEWER METHODS IN DIAGNOSIS
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TREATMENT• There is no available treatment capable of
altering the course of acute hepatitis. Prevention is the most effective approach against the disease.
• As hepatitis E is usually self-limiting, hospitalization is generally not required. However, hospitalization is required for people with fulminant hepatitis and should also be considered for infected pregnant women.
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Maintaining quality standards for public water supplies ;
Establishing proper disposal systems to eliminate sanitary waste.
PREVENTION
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PREVENTION• Maintaining hygienic practices such as hand
washing with safe water, particularly before handling food;
• Avoiding drinking water and/or ice of unknown purity;
• Avoiding eating uncooked shellfish, and uncooked fruits or vegetables that are not peeled or that are prepared by people living in or travelling in highly endemic countries
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• China has produced and licensed the first vaccine to prevent hepatitis E virus infection, although it is not yet available globally.
VACCINATION - UPDATE
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• Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in the
Developing World