2. What is hepatitis?
•Hepatitis refers to an inflammatory
condition of the liver. It’s commonly
caused by a viral infection
3. Where is liver located and what are its
functions
• Liver is located in the right upper area of your abdomen.
It performs many critical functions that affect metabolism throughout your body,
including:
• bile production, which is essential to digestion
• filtering of toxins from your body
• excretion of bilirubin (a product of broken-down red blood cells), cholesterol,
hormones, and drugs
• breakdown of carbohydrates, fats, and proteins
• activation of enzymes, which are specialized proteins essential to body functions
• storage of glycogen (a form of sugar), minerals, and vitamins (A, D, E, and K)
• synthesis of blood proteins, such as albumin
• synthesis of clotting factors
4. The 5 types of viral hepatitis
• Viral infections of the liver that are classified as hepatitis include
hepatitis A, B, C, D, and E. A different virus is responsible for each
type of virally transmitted hepatitis.
• Hepatitis A virus (HAV), causing a faecally-spread self limiting
disease.
• Hepatitis B virus (HBV), causing a parenterally transmitted disease
that may become chronic.
• Hepatitis C virus (HCV), previously termed non-A, non-B (NANB)
hepatitis virus involved chiefly in transfusion-related hepatitis.
• Hepatitis delta virus (HDV) which is sometimes associated as
superinfection with hepatitis B infection.
• Hepatitis E virus (HEV), causing water-borne infection.
5. Hepatitis A
• Hepatitis A is caused by an infection with the hepatitis A virus (HAV).
This type of hepatitis is most commonly transmitted by consuming
food or water contaminated by feces from a person infected with
hepatitis A.
• Infection with HAV causes hepatitis A (infectious hepatitis or infective
hepatitis).
• Hepatitis A is responsible for 20-25% of clinical hepatitis in the
developing countries of the world but the incidence is much lower in
the developed countries.
6. • Hepatitis A is usually a benign, self-limiting disease
and has an incubation period of 15-45 days.
• It is almost exclusively spread by faeco-oral route. The
spread is related to close personal contact such as in
overcrowding, poor hygienic and sanitary conditions.
• Frozen and stored contaminated foods and water have
been blamed in many epidemics. Most frequently
affected age group is 5-14 years; adults are often
infected by spread from children.
7. About hepatitis A virus
• HEPATITIS A VIRUS (HAV) The etiologic agent for hepatitis A,
HAV, is a small, 27 nm diameter, icosahedral nonenveloped, single-
stranded RNA virus.
8. PATHOGENESIS
• Hepatitis A virus is present in the liver and replicates there.
• Evidence that hepatitis caused by HAV(hepatitis A virus) has an
immunologic basis comes from demonstration of following antibodies
acting as serum markers for hepatitis A infection.
1. IgM anti-HAV antibody appears in the serum at the onset of
symptoms of acute hepatitis A.
2. IgG anti-HAV antibody is detected in the serum after acute illness
and remains detectable indefinitely. It gives lifelong protective
immunity against reinfection with HAV.
9.
10. Signs and symptoms
• Hepatitis A signs and symptoms typically don't appear until you've had the virus
for a few weeks. But not everyone with hepatitis A develops them. If you do,
hepatitis signs and symptoms can include:
• Fatigue
• Sudden nausea and vomiting
• Abdominal pain or discomfort, especially on the upper right side beneath your
lower ribs (by your liver)
• Clay-colored bowel movements
• Loss of appetite
• Low-grade fever
• Dark urine
• Joint pain
• Yellowing of the skin and the whites of your eyes (jaundice)
• Intense itching
• These symptoms may be relatively mild and go away in a few weeks. Sometimes,
however, hepatitis A infection results in a severe illness that lasts several months.
11. Diagnosis
• Detection of HAV-Specific Antibodies
The humoral immune response plays the pivotal role in the diagnosis of
HAV infection and the differentiation of hepatitis A from other types of
viral hepatitis.
There are a number of commercially available assays for the detection
of IgM and total anti-HAV IgM, IgA, and IgG anti-HAV are usually
present at the onset of symptoms.
Why serologic testing is required?
Since hepatitis due to HAV infection is clinically indistinguishable from
disease caused by other hepatitis viruses (i.e., HBV, HCV, HDV, and
HEV), serologic testing is required to make the diagnosis.
12. • A number of methods have been used to detect this virus-specific
antibody class, including radioimmunoassay, immunochemical
staining enzyme-linked immunosorbent assay, immunoblotting, and
dot blot immunogold filtration.
• HAV has also been detected with techniques such as
restriction fragment length polymorphism
single-strand conformational polymorphism
Southern blotting nucleic acid sequencing-based amplification
nucleic acid hybridization
reverse transcription-PCR (RT-PCR) and antigen capture RT-PCR .
Recent update-Amplification of viral RNA by RT-PCR is currently the
most sensitive and widely used method for detection of HAV RNA.
