Najran University College of Applied Medical Sciences

1. Najran UniversityCollege of Applied Medical Sciences Hepatitis viruses BY Dr. Ahmed MoradAsaad Associate Professor of Microbiology Coordinator of Applied Medical Sciences College

2. Hepatitis viruses • A group of unrelated viruses affecting the live • 5 groups are now described: • Hepatitis A virus (HAV) • Hepatitis B virus (HBV) • Hepatitis C Virus (HCV) • Hepatitis D virus (HDV) • Hepatitis E virus (HEV) • The severity and course of the disease is variable • - After a prodroma of fever – upper GIT upset, the manifestations of liver affection appear

4. Hepatitis A virus • The causative agent of infectious (epidemic) hepatitis • RNA virus to picornaviruses (now as Retrovirus 72) • Only one serotype is known • No cross-reactivity with other hepatitis viruses • It is destroyed by: • Boiling in water for 5 minutes • Autoclaving at 121 C for 20 minutes • UV irradiation • Treatment with formalin or chlorine

5. Hepatitis A virus • Infection occurs by contaminated food and water • Common among children and young adults • The incubation period is 14 – 50 days • The virus is present in stool during IP and persist for 3 – 4 weeks after recovery • No carrier state • A single immunologic type • Life-long immunity follows infection

6. Hepatitis A virus • Laboratory Diagnosis: • Abnormal liver functions (Bilirubin – transaminases) • Detection of Anti HAV Abs: By ELISA • Anti HAV IgM: Diagnostic of acute illness • Anti HAV IgG: Convalescence – immunity • 3. Detection of HAV particles: By PCR • In liver – bile – stool and blood

7. Hepatitis A virus • Prevention: • 1- Control measures for prevention of fecal contamination of food and water • 2- HAV vaccine (Havrix): Formalin inactivated vaccine for: • Persons above 2 years of age • Travelers to developing countries, military groups and medical staff • Two doses by i.m.: initial dose followed by a booster dose 6-12 months later. • 3- Immune globulin given 1 – 2 weeks after exposure to HAV

8. Hepatitis B virus • Hepatitis B: Varying from acute fulminant hepatitis to anicteric, asymptomatic to chronic hepatitis that ranges from benign to malignant forms • The disease may remain clinically silent for years but suddenly it may progress to cirrhosis and hepatocellular carcinoma • The virus is more resistant to heat – chemicals than HAV. It can survives dryness for years • It can be destroyed by: • Boiling in water for 10 minutes • Autoclaving

9. Viral agent The complete infectious virion (Dane particle) is a 42 nm spherical particle formed of: 1- Outer lipoprotein envelope (HBs Ag) 2- Internal core of nucleocapsid protein (HBc Ag) surrounding DNA genome 3- A hidden antigenic component of the core (HBe Ag)

10. Epidemiology • Transmission: • *- Blood and blood products are most important • *- Saliva and semen in venereal transmission • Populations at risk: • *- Healthcare workers • *- Intravenous drug users • *- Renal dialysis patients • *- Infants born to infected mothers • *- Sexual partners of HBV carriers • Complications: • 1- Fulminant hepatitis 2- Chronic active hepatitis • 3- Chronic persistent hepatitis 4- Cirrhosis • 5- Hepatocellular carcinoma

11. Laboratory diagnosis of HBV • Depends on detection of circulating viral antigens and antibodies • Antigens: • HBs Ag: Present before and after the onset of disease and persists for about 3 months and may remain for years in carriers • HBc Ag: Not detected in serum but present in nuclei of infected liver cells • HBe Ag: Present in acute phase of the disease (indicator of active disease)

12. Antibodies: • Anti HBs Ab: Correlated with immunity • Anti HBcAb: Appear during infection • Anti HBeAb: Present in acute phase of the disease (indicator of active disease) • Markers of HBV infections