HEPATITIS B VIRUS (HBV) INFECTION

Hepatitis B virus (HBV) infection is the most chronic and contagious viral infection especially in those infected as infants. It is the major factor in the eventual development of liver disease and hepatocellular carcinoma in those individuals.  Millions of persons worldwide are chronically infected with HBV, and approximately one third of world population has been exposed to HBV. The frequency of chronic HBV is high in Asia and Africa. In acute state, about 30% to 50% of adolescents and adult with hepatitis B virus infection develop jaundice. Symptoms to children infected with HBV are mostly silent. Hepatitis B surface antigen appears 1 to 2 months after infection, and it is the last protein marker to disappear when the infection resolve. We will discuss occult HBV infection in our subsequent publication.

MODE OF TRANSMISSION

• Through body fluids
• Parenteral drug abusers
• Sexual contact
• Institutionalized persons
• From mother to child, usually at or after delivery (termed vertical transmission)
• Since the mandatory screening of blood donors for HBsAg was instituted, the number of cases of transfusion-associated hepatitis has been on the decline, otherwise people can be infected through infected unscreened blood.
• People have been infected by improperly sterilized syringes, needles, or scalpels and even by tattooing or ear, nose, tongue and body piercings.
• HBsAg can be detected in saliva, nasopharyngeal washing, semen, menstrual fluid, vaginal secretions, as well as blood.

TREATMENT   

IMMUNIZATION

Hepatitis B virus infection may be prevented by either passive (hepatitis B immune globulin HBIG, or active (hepatitis B recombinant vaccine) immunization.

DIAGNOSTIC TEST FOR HEPATITIS V VIRUS

1. Hepatitis B surface antigen (HBsAg) is produced in excess by the virus, and is used as a laboratory test to detect current HBV infection. It typically presents with both acute and chronic infection. For persons who have recovered from the infection or who has developed immunity through vaccination Antibody to the Hepatitis surface antigen is present in blood and most individuals develop antibody to Hepatitis core antigen (anti-HBc) alongside.
2. Antibody to the Hepatitis B core antigen (HBcAb) is the most commonly detected antibody against HBV. Two assays are usually employed: IgM and IgG antibodies, and is usually positive for life after exposure. IgM anti-HBc is usually positive for 3 months to 6 months after acute infection, but is occasionally present with chronic HBV infection.
3. Hepatitis B envelope antigen (HBeAg) and antibody against Hepatitis B envelope (HBeAb) are typically used in setting with chronic HBV infection. Firstly, HBeAg is seen in replicating viral particles, in other words it presence connotes the chance of having high level viral copies. It is used as a maker of persistence of infectious virus; its clearance and the appearance of antibody to Hepatitis B envelope (HBeAb) have been used as indicators of conversion to nonreplicating state and as a goal of antiviral treatment.

HEPATITIS B VIRUS DNA test

This is the direct measure of circulating virus. Viral copies above 2000 copies/mL is clinically significant level of viremia.

Studies has shown that the risk of complication increases with viral loads between 2000 and 10,000 copies/mL. With treatment, the first evidence of response is a fall in HBV DNA.

Initially, vaccination was targeted toward high-risk individuals, such as

1. Babies of infected mothers,
2. Individuals with promiscuous sexual practice and deranged appetite,
3. Healthcare workers, and
4. Those having sexual contact with infected persons.

Today, everyone needs to be vaccinated.

PROPHYLAXIS

In the case of exposure to someone suspected or confirmed to have hepatitis B virus, a prophylaxis of immune globulin should be administered.

CARRIER STATE:

The carrier state is defined on the basis of longitudinal studies as persistence of the hepatitis B surface antigen in the circulation for more than 6 months. The carrier state may be life-long and may be associated with liver damage varying from minor changes in the liver cells to persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma. Several risk factors have been identified in relation to the development of carrier state. It is commoner in males, more likely to follow infections acquired in childhood, than those acquired in adult life and more likely to occur in patients with natural or acquired immune deficiencies.

Note: patients with acute Hepatitis B virus infection generally does not need to b isolated or stigmatized, so long as blood and instrument precautions are stringently observed, both in the general patient care areas and in the laboratories. Because spouses and intimate contacts of persons with acute hepatitis B are at risk of acquiring clinical hepatitis B virus, they need to be informed about might increase the risk of infection or transmission, therefore need to get vaccinated. There is no evidence that HBsAg positive persons who handle food, pose any health risk to the public.

References

CURRENT Medical Diagnosis and Treatment 2013 Papadakis et. al.

TIETZ Fundamentals of Clinical Chemistry Burtis et. al.

Jawetz, Melnick, & Adelberg’s Medical Microbiology 23rd edition.