Hepatitis A Virus (HAV)

What sample is needed for the Hepatitis A Virus?

1. Venous blood is needed to prepare the serum.
2. Random sampling can be used.
3. The serum can be stored at 4 °C for 5 days.
4. Feces can be taken for immuno-electron microscopy.

What are the Indications for Hepatitis A Virus?

• To diagnose viral hepatitis A (HAV) infection.

How will you define Hepatitis A Virus (HAV)?

1. Hepatitis A viral infection is also called Infectious hepatitis or short incubation hepatitis.
2. Hepatitis A is a non-enveloped virus belonging to the hepatotropic virus family and is 27 nm in diameter.
3. HAV belongs to the Picornaviridae family.
   1. It is a picornavirus.
   2. The genus is a hapatovirus.
4. There is no cross-reactivity with HBV or other hepatotropic viruses.

How will you describe the structure of the Hepatitis A Virus?

1. It comprises a linear single-stranded RNA virus (ssRNA) genome with 7.5 kb.
2. It measures 27 to 32 nm spherical particles with cubic symmetry.
3. VPg is a Viral protein genome-linked. It is a protein attached to the positive strand of viral RNA.
   1. VPg acts as a primer during RNA synthesis.
4. HAV is a self-limiting acute liver disease.

What is the incubation period for Hepatitis A virus infection?

1. The incubation period is short, 3 to 4 weeks (range is 2 to 6 weeks).
2. It is highly infectious during active infection and is excreted in the stool.
3. It will spread through contaminated water or food.
4. Urine and live viruses are less infective than stool.
5. A great number of the virus appears in the stool before the symptoms appear.
6. The number of viruses decreases as the symptoms appear.
7. Complete recovery in 1 to 3 weeks and no carrier state.
8. An occasional patient may have the longer disease for almost one year.

What is the mode of the spread of HAV infection?

1. Initially, E/M found it in the stool and liver.
   1. Saliva and urine are less infective than stool.
2. It is a highly contagious viral infection and is most common in children.
   1. It is common in daycares and orphanages.
   2. It is also common in mentally retarded children.
   3. Most children recover from the disease and develop lifelong immunity.
3. In the active stage, this virus is excreted in the stool and is very infective. It is in greater amounts in the stool before the patient gets symptoms.
4. So, there is an oro-fecal spread because of food and drink contamination.
5. Sexual transmission between male homosexuals has been reported.
6. Transmission via blood transfusion and I/V drug use is rare.
7. It is most common in the third world, almost 90% to 100%.

How will you describe the clinical course of Hepatitis A virus (HAV)?

1. Mostly asymptomatic.
   1. In adults, only 10% are asymptomatic.
2. >50% of cases are subclinical, anicteric hepatitis, including almost all infants. 75% of the children are <2 years of age, and 60% are 4 to 6 years.
3. The most common age group is children.
4. There may be a prodromal period of fever, chills, fatigue, malaise, and headache.
   1. The above symptoms will be followed by nausea and vomiting.
5. There is anorexia.
6. Sometimes, there may be abdominal pain, which is usually in the upper quadrant.
7. Sometimes, there may be gastroenteritis.
8. When jaundice appears, then there is rapid improvement in the clinical symptoms.
   1. Jaundice may last for a few days to 12 weeks.
   2. Usually, it is not infective after the appearance of jaundice.
9. One report says that 8% to 10% of the cases have a fluctuating course with variations in laboratory tests, which may last as long as 12 to 15 months.
10. Like hepatitis C and B viruses, it does not cause chronicity (chronic liver disease).

What is the outcome of Hepatitis A Virus infection?

1. There is mild to severe disease.
2. Mostly recovered from the HAV infection and gets life-long immunity.
3. Very few die of HAV infection with fulminant hepatitis.

How will you Summarize HAV infection?

What are the high-risk groups for the Hepatitis A Virus infection?

1. Child-care centers.
2. The family members who are in close contact with the patient.
3. In the summer camps.
4. People are working in correctional centers.
5. Homosexual peoples.

How will you describe the immunology of the Hepatitis A Virus?

1. The first antibody in acute infection is IgM type (HAV-IgM)
2. IgM appears 3 to 4 weeks after exposure to the virus or before the liver function tests are raised.
   1. IgM returns to normal in roughly 8 weeks or disappears in 3 to 4 months. It is not detectable after 12 months.
3. HAV-IgG appears after 2 weeks when IgM is increasing.
   1. IgM is slowly normal, and IgG will appear in the blood.
   2. HAV-IgG will be detectable in the blood even after 10 years.
4. Sometimes, epidemics are confined to adults and are associated with eating contaminated food or shellfish from contaminated water supply.
5. In the USA, 40% to 50% of adults tested positive for HAV antibodies.
6. This antibody positivity may reach 90% to 100% in the third world.

What are the outcomes of HAV infection?

What is the outcome of the Hepatitis A Virus (HAV)?

1. Chronic disease = Not reported.
2. Carrier state = Not reported.
3. Infectivity = HAV-RNA
4. Recovery = Mostly complete.

How will you diagnose the Hepatitis A Virus?

1. SGPT and SGOT have raised the range to hundreds of the normal, which may remain for 1 to 3 weeks.
2. Blood shows relative lymphocytosis.
3. HAV-IgM
   1. IgM is macroglobulin, and it indicates acute infection.
   2. It appears in the blood 3 to 4 weeks after exposure to the HAV virus.
   3. Or it appears just before the rise in SGPT.
   4. The peak level reaches one week after the rise begins.
   5. It appears simultaneously when symptoms appear.
   6. It becomes normal in about 2 months after the clinical symptoms become normal,
   7. It is non-detectable for 12 months. In a few cases, it may be detected in 12 to 14 months.

1. HAV-IgG
   1. It appears after 2 weeks of the beginning of IgM increase.
   2. It is seen in the middle stage of the symptoms.
   3. It peaks in about 1 to 2 months after it begins to rise.
   4. Its titer will fall and remain low titer for at least 10 years.
   5. The rising titer is needed in only IgG-positive cases.
2. HAV-IgG positive and HAV-IgM negative:
   1. It indicate convalescent or chronic stage.
   2. Anti-HAV- IgG is present throughout life. It is positive in 50% of the USA population, indicating past infection and immune status.
   3. HAV total antibody indicates present or past infection.
   4. HAV total antibody also indicates vaccination.
3. PCR:
   1. In the early stage, antibodies are not detectable. Only PCR for RNA can be found in the stool and blood.
   2. PCR for RNA may be found in the saliva as well.
   3. PCR is rarely needed.
4. HAV antigen:
   1. The fecal HAV virus is positive 2 weeks before the symptoms appear.
   2. The HAV virus can be detected in the stool as early as 1 to 2 weeks after exposure.
   3. This period ends about 1 to 4 days after the appearance of the symptoms.
   4. At admission in 40% to 64% of the patients, the HAV virus in stool is negative.
5. Summary of HAV virus diagnosis:
   1. For acute infection (current or recent HAV infection) = HAV-IgM.
   2. Past HAV infection/immunity = HAV-antibody total.

How will you Prevent the Hepatitis A Virus?

1. The best way is to give the vaccine to children in epidemic areas.
2. Improve:
   1. Safe water supply.
   2. A safe food supply is the best hygiene.
   3. Have good sanitation.
   4. Washing of hands before taking the food.

How will you treat the Hepatitis A Virus?

• These patients recover without any treatment.
• Mainly, there is a need for supportive treatment.

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