1. Hepatitis in a surgeon- problem oriented learning: Part II Paul Froom MD, MOccH Chief of Epidemiology Israel- National Institute of Occupational and Environmental Health Associate Professor of Epidemiology Sackler School of Medicine, Tel Aviv University

2. Primary purpose of the lecture Learn about the risk and prevention of infectious diseases (HIV, HBV, HCV) in health care workers and in their patients Learn the following terms: infectivity, virulence, pathogenicity, host, reservoir,carrier, common source, propagated disease, colonization, epidemics,

3. Surgeon with HIV 3 per 1000 = infectivity Nearly universally fatal Seroconversion within 3 months Cumulative risk to surgeons; 1% low risk areas, 10% high risk areas identified exposure: treat with antiviral drugs decreased transmission rate- 79%

4. Surgeon with hepatitis C NO vaccine 2,000 cases of HCV in HCWs reported annually in the USA Prevalence- 0.5-18% in hospitalized patients infectivity: 0-10% Chronic liver disease, cancer of the liver

5. Ideal Hospital program Vaccination of all HCWs for HBV Periodic lectures on the risk of infection- required Double gloving, check gloves after surgery for perforations Check hands of surgeon for injury

6. Ideal Hospital program (2) Procedures for drawing and distributing blood Visors for surgery provided Injured HCWs- patients checked for HIV, HBV and HCV If exposed to HBV: give booster dose of vaccine and hepatitis B immune globulin

7. Ideal Hospital program (3) Exposure to HIV: three drugs given Sexual partners of the HBV infected HCW should be vaccinated

8. Other terms: Host (1) person or animal who lodges the infectious agent E.g. the surgeon is the host for hepatitis B if he passes on the disease to his patients.

9. Reservoir (2) Any place, person, animal, arthropod, plant, soil or substance or combination of these in which an infectious agent normally lives and multiplies or survives. E.g. Our surgeon and other humans are the reservoir for hepatitis B infection.

10. Carrier (3) Person or animal who is well, yet harbors the infectious agent and serves as a potential source of infection The surgeon is a carrier if his liver biopsy is normal definition of well??

11. Colonization (4) Multiplication of infectious agents in the body of man or animal. Includes both symptomatic and asymptomatic infections Our surgeon is colonized with hepatitis B.

12. Epidemic transmission Epidemic is the occurrence of a cohort of cases of an illness which is clearly in excess of normal expectancy. Gynecological surgeon who infected 9% of his patients is an epidemic Common source: single source for infection: most common food poisoning.

13. Epidemic transmission (2) Propagated disease: disease from multiple sources E.g. Surgeon infected his patients who infected their family members, etc. Herd immunity: Protection of all members of the group from spread of the infectious agent if nearly all are immunized.