Transcript Case Study
Hepatitis in a surgeonproblem 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 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, 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% 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 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 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 Ideal Hospital program (3) • Exposure to HIV: three drugs given • Sexual partners of the HBV infected HCW should be vaccinated 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. 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. 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?? 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. 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. 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.