Geographic distribution of hepatitis E

1
Geographic distribution of hepatitis E
Kar Prevention of transmission

• Hepatitis E virus
• Enterically transmitted non-A, non-B hepatitis
• Caused by a non-enveloped single stranded RNA
  virus
• Initially classified in Caliciviridae family
• Currently classified into separate genus
  Hepatitis E-like viruses Arch Virol 2000 145
  1421-1436

CDC
2
Kar Prevention of transmission

• Epidemiological features
• Outbreaks of HEV have occurred over a wide
  geographic areas primarily in developing
  countries
• Accounts for gt 50 of acute sporadic hepatits in
  both childrens and adults in some high endemic
  areas1
• Occurrence of sporadic HEV infection in humans
  may maintain transmission during interepidemic
  periods
• A nonhuman reservoir is possible
• Most outbreaks associated with fecally
  contaminated drinking water
• Minimal person to person transmission2
• Nosocomial transmission has been reported to
  occur3
• Some studies has shown the possibility of post
  transfusion hepatitis E 4
• Not transmitted by sharing utensils, cigarettes,
  kissing

1. J Med Virol 43 281, 1994 2. J hepatol 20
567, 1994 3. Lancet 339 1424,1992 4. J Viral
Hepat 1999 6 161-164
3
Kar Prevention of transmission

• Hepatitis E a serious public health problem
• Accounts for gt 50 of AVH in young adults of
  developing countries
• Only 1-3 of non-pregnant patients progress to
  FHF
• Case fatality rate can be as high as 20 among
  pregnant patients1
• No effective treatment currently exists
• Only effective management prevention
• General measures
• Passive Immunoprophylaxis
• Active Immunoprophylaxis
• 1. Curr Infect Dis Rep 2002 4 118-123

4
Kar Prevention of transmission

• General measures
• Improved sanitation
• Provision of clean water source - principal
  preventive maneuvers during an epidemic
• Boiling water appears to inactivate HEV
  effectively- limited studies
• 2. Travelers to endemic areas should advised to
  avoid
• Drinking water or brewages with ice source of
  unknown purity
• Eating uncooked and unpeeled fruits and vegetables

5
Kar Prevention of transmission

• Passive Immunoprophylaxis (Limited studies)
• IgG prepared from plasma collected in non-HEV
  endemic areas is not effective in preventing
  clinical disease during hepatitis E outbreaks.
• Efficacy of IgG prepared from plasma collected in
  HEV endemic areas is unclear.
• In India no statistically significant difference
  in disease rates have been found after
  administration of immunoglobulin1,2 (1. Indian
  Gastroenterol 11113, 1992 2. Indian J Med Res
  8118, 1985)

6
Kar Prevention of transmission

• Active immunoprophylaxis
• No commercial vaccines for hepatitis E available.
  Development of an attenuated or killed vaccine is
  currently not possible lacking an efficient
  cell culture system for replication of HEV
  (Vaccine 2003 22 257-267)
• Nucleic acid-based vaccine/recombinant protein
  vaccine are current candidates. It may be
  possible to produce a broadly protective vaccine
  as only one serotype has been identified
• ORF2-encoded protein of HEV is the most promising
  subunit vaccine candidate because it possesses a
  good antigenicity has been identified
• Only one HEV vaccine candidate progressed to the
  stage of clinical trials
• 56 KU (expressed in insect cells from a
  baculovirus vector) recombinant vaccine developed
  at the NIH, USA (Lancet 2000 355 1623)
• Phase II/III clinical trials currently under
  progress in Nepal (Vaccine 2003 21 2607-2615)