A discussion o Hepititis A

1. Hepatitis A
Jim Taylor
BIOL 211
Summer 2014
Ivy Tech Lafayette

9. The Pathogen

10. The HAV virus is the unique member of the
genus hepatovirus of the picornavirus family.

11. It has a single strand, 3 '-polyadenylated
positive sense RNA genome.

12. The RNA is surrounded by a naked (unenveloped)
icosahedral capsid that is around 28 nm in
diameter.

13. At the 5' end of the RNA strand is a viral
protein called VPg

14. There is only one serotype of HAV.
Genus: Hepatovirus
Species: Hepatitis A virus (type species of genus)
hepatitis A virus 1
(formerly enterovirus 72)

15. Genetic heterogeneity between HAV isolates from
different parts of the world has enabled the
classification of HAV strains into seven different
genotypes, designated I to VII, four of which are
human pathogens.

16. HAV genotype classification
• A genotype is defined as a group of viruses with > 85% nucleotide
identity
• A sub-genotype is defined as a group of viruses with sequence
variability of less than 7.5%
3 human genotypes
– genotype I >90%
– genotype III < 10%
– genotype II 2 isolates
• 3 simian genotypes

17. Genotype IA appears to be the agent responsible
for the majority of hepatitis A cases worldwide
and has been isolated from all parts of the world.

18. Geographical distribution areas can be
characterized as having high, intermediate or low
levels of hepatitis A infection.

20. Pathology

21. Hepatitis A is a liver disease caused by the
hepatitis A Virus

22. The Virus is primarily
spread when an uninfected (and unvaccinated)
person ingests food or water that is
contaminated with the feces of an infected person

23. The clinical case definition for acute viral hepatitis
is
1) discrete onset of symptoms (e.g., nausea,
anorexia, fever, malaise, or abdominal pain)
and
2) jaundice or elevated serum aminotransferase
levels.

24. Because the clinical
characteristics are
the same for all
types of acute viral
hepatitis, Hepatitis
A diagnosis must be
confirmed by a
positive serologic
test for
immunoglobulin M
(IgM) antibody to
Hepatitis A virus

25. Hepatitis A is ingested and enters the bloodstream
through the epithelial lining of the intestines to
reach the liver.

26. The virus replicates in liver cells and is released
into the bile, and then into the stool for about 2
weeks before the onset of clinical illness and up to
1 week after.

27. The disease is most infective just before the onset
of jaundice. Clinically the disease has an
incubation period of 2-3 weeks

28. The majority of illnesses end in 3-6 weeks

29. Rarely the disease may be very severe with
fulminant (rapid severity) hepatitis, liver coma and
death.

30. Treatment

31. The first descriptions of hepatitis
(epidemic jaundice)
are generally attributed to Hippocrates.

32. There is no specific treatment for hepatitis A.

33. Improved sanitation, food safety and
immunization are the most effective ways to
combat hepatitis A.

34. Summary

35. It has a single strand, 3 '-polyadenylated
positive sense RNA genome.

36. Geographical distribution areas can be
characterized as having high, intermediate or low
levels of hepatitis A infection.

37. The Virus is primarily
spread when an uninfected (and unvaccinated)
person ingests food or water that is
contaminated with the feces of an infected person

38. There is no specific treatment for hepatitis A.

39. Improved sanitation, food safety and
immunization are the most effective ways to
combat hepatitis A.

40. References
This is a partial list. The full list is available upon request.
• http://pathmicro.med.sc.edu/virol/hepatitis-virus.htm
• http://www.who.int/csr/disease/hepatitis/whocdscsredc2007/en/i
ndex2.html
• http://ci.vbi.vt.edu/pathinfo/pathogens/HAV_2.html
• http://www.who.int/mediacentre/factsheets/fs328/en/
• http://www.cdc.gov/hepatitis/HAV/index.htm
• http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/hepa.pdf
• http://www.mayoclinic.org/diseases-conditions/hepatitis-
a/basics/definition/con-20022163