Hepatitis
B is an infection caused by Heptatitis B Virus, and is divided into 2 types:
-
Acute
Hepatitis B: newly acquired infections. Symptoms usually appear after 1 to 4
months of infecion. Symptoms usually resolve for most patients after few
months, with a small number of patients developping fulminant hepatitis, which
a life-threatening form of acute hepatitis.
-
Chronic
hepatitis B are patients who symptoms did not resolve completeley, lasting longer
than 6 months. Chronic hepatitis B infection is permanent. Chronic hepatitis B
infection is more prominent and severe in children.
Transmission:
HBV is a blood borne virus, transmitted through blood or mucous. Moreover, it
is transmitted from infected pregnant mother to fetus. People at high risk of
getting infected with HBV virus include: sexual relationship with an infected
person, illicit drug use, needle stick in case of healthcare workers and
clinical laboratory workers, newborns for mothers with infection.
HBV
virus enters the host cells by binding to an unknown receptor, and being
endoctyosed. Chaperones transfer the viral DNA to host nucleus where its DNA is
transformed into covalently closed circular DNA from whcih four viral mRNAs are
made. Those newly formed mRNA are used to make new copies of the viral genome
and capsid core protein and viral DNA polymerase. These then undergo further
processing to from virions that are released from the cell for further
infection or return to the nucleus to make more copies.
Early
symptoms of HBV infection include: fatigue, itching, appetite loss, jaundice,
dark urine, clay colored stool and nausea and vomiting and dehydration.
Patients experience fulminate HBV infection also experience symptoms associated
with hepatic encephalopathy.
http://www.britishlivertrust.org.uk/data/5/content/6/628/imgs/HBV%20Nat%20Hist.JPG |