hepatitis virus B Flashcards
what are the types of hepatitis viruses
Hepatitis Viruses - A,B,C,D,E
Other viruses – Cytomegalo, EBV, HSV, Yellow fever, Rubella, Enteroviruses etc.,
for hepatitis b, what is the route of transmission, causative agent, chronic liver disease condition and vaccine available?
parenteral, std route of transmission
hepadnaviridae
yes chronic liver disease
recombinant vaccines available
what is hepatitis b virus
HBV is the most wide spread and important type of viral hepatitis.
More than 1/3rd of the world’s population is estimated to be infected by Hepatitis B Virus.
Patient will develop serious liver disease - chronic hepatitis, cirrhosis & primary hepatic cancer.
what is the mophology of HBV
HBV is a DNA virus with - an outer envelope, an inner core - enclosing the viral genome & DNA polymerase.
The outer envelope contains – 2 structural particles
i) - A small, spherical particle - is predominant in the serum
ii) - A filamentous / tubular particle
what are the antigens found on HBV
These two are antigenically identical & are surface components of HBV - HBsAg /Australian antigen.
The inner core is - A double walled spherical particle is called as core -
Core antigen (HBcAg/ Dane particle)
A 3rd Antigen called HBe Ag is derived from the HBcAg.
HBe Ag is found in the plasma during the DNA replication.
describe the DNA of HBV
The DNA contain both (+) ve & (-) ve strand.
The viral DNA polymerase has 2 functions - DNA dependent DNA polymerase
- RNA dependent reverse transcriptase
The virus replicates within Hepatocytes.
where can we see hbv dna
we Can see the HBV DNA and viral proteins in - Bone marrow, Spleen, Lymphnodes & - Circulating Lymphocytes.
how is HBV inactivated
HBV will be inactivated - at 60°C for 1 hour & in 2% glutaraldehyde for 10mins
what are the pathogenesis and clinical features of HBV
The incubation period is from 40 days - 6 months usually 2 - 3 months.
Causes prodromal illness - malaise, anorexia, weakness, arthralgia, myalgia, yellow eye /skin
In acute case
The patient usually begins to better when the jaundice appears.
The stool is pale and urine is dark yellow.
- Bilurubin,
- SGOT (AST) & SGPT (ALT) are in higher level
What happens in acute cases of HBV
In acute case
In this stage the virus replicates in the hepatocyte.
- Viral DNA & C antigen - occur in the Nucleus
- S antigen occur in the cytoplasm
- E antigen occur in the cell membrane.
what do both b and t cells do in HBV
Both B & T cells - damage the hepatocells by - Antibodies, Natural killer cells & Tc cells
causes sign of
- Inflammation in the portal triads
- lymphocytic infiltration occur in the liver parenchyma –
- a single cell show balloon like appearance
- form acidophilic bodies (councilman) & then the parenchyma cells die.
what happens with hbv in the absence of adequate immune response
In the absence of adequate immune response,
- HBV infection may not cause Hepatitis,
- but is in the form of carrier state.
Infant & Immunodificient person are more like asymptomatic carriers
what happens in chronic hepatitis in HBV
In chronic hepatitis
- damage extends out from the portal tracts,
- giving the piecemeal necrosis appearance.
Some lobular inflammation is also seen,
- Develop fibrosis
- lead to cirrhosis.
what is hepatrocellular carcinoma
Hepatocellular carcinoma (HCC) - is one of the 10 most frequent tumours in the world, where infection occurs at a very early age.
This is necessary as there may be an interval 30 - 40 years between infection – to —- tumor development.
The viral DNA can be found in the tumor cells and usually associated with cirrhosis.
HBV is present in the blood, body fluids - semen, vaginal secretions, saliva.
Mostly the virus spread through
- blood transfusion
- sexual transmission.
what are the laboratory diagnosis of HBV
Detect - HBV antigens & antibodies using - Radioimmuno assays (RIA)
- ELISA
Detect – HBsAg (is the first marker to appear in blood after infection).
HBcAg is not circulate in the blood, but detect Anti-HBcAg antibodies in the blood.
HBeAg is circulating along with HBsAg
Circulating HBeAg is an indicator of active intrahepatic viral replication.
