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•Good sanitation measures are essential for preventing environmental contamination.•Good personal hygiene is also essential for prevention and control including:–Hand washing with soap:•After using the bathroom•After changing a diaper•Before preparing and eating food
Hepatitis B•Hepatitis B is caused by infection with the Hepatitis B virus (HBV), the prototype member of the hepadnavirus family–HBV is the only human representative of this family. –It has a circular DNA genome of 3.2 kb•Currently, eight genotypes (A−H) are identified by a divergence of >8% in the entire genome
Hepatitis B Characteristics•A Hepadnaviridae – partially double-stranded DNA virus•HBsAg – stimulates protective antibodies, a marker for current infection•HBcAg – localized within liver cells, identifies acute infection, anti-HBcAg persists for life and is a marker of past infection•HBeAG – a marker of active replication and infectivity
Hepatitis BSource: J Viral Hepat. 2010 Apr;17(4):229-35. Hepatitis B virus: origin and evolution.
Hepatitis BEpidemiology•Worldwide, HBV is the primary cause of liver cancer–For males, it is the third leading cause of cancer mortality–For females, it is the sixth leading cause of cancer mortality
Hepatitis BEpidemiology•An estimated 800,000–1.4 million persons in the United States have chronic HBV infection. •Chronic infection is an even greater problem globally, affecting approximately 350 million persons. •An estimated 620,000 persons worldwide die from HBV-related liver disease each year.
Hepatitis BEpidemiology•The incubation period from the time of exposure to onset of symptoms is 6 weeks to 6 months. •HBV is found in highest concentrations in blood and in lower concentrations in other body fluids (e.g., semen, vaginal secretions, and wound exudates). •HBV infection can be self-limited or chronic.
Hepatitis BIn adults, only approximately half of newly acquired HBV infections are symptomatic, and approximately 1% of reported cases result in acute liver failure and death.
Hepatitis BDiagnosis•Hepatitis B is detected by looking for a number of different antigens and antibodies:–Hepatitis B surface antigen (HBsAg): •A protein on the surface of HBV; it can be detected in high levels in serum during acute or chronic HBV infection. •The presence of HBsAg indicates that the person is infectious. •The body normally produces antibodies to HBsAg as part of the normal immune response to infection. •HBsAg is the antigen used to make Hepatitis B vaccine.
Hepatitis BDiagnosis•Hepatitis B is detected by looking for a number of different antigens and antibodies:–Hepatitis B surface antibody (anti-HBs): •The presence of anti-HBs is generally interpreted as indicating recovery and immunity from HBV infection.