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Viral Hepatitis

Viral Hepatitis

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Viral Hepatitis

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  1. Viral Hepatitis

  2. Hepatitis A Virus

  3. 1. Epidemiology Has a worldwide distribution (low, intermediate & high endemicity). Highest levels of endemicity in regions with low standards of sanitation. Adults of high endemicity are usually immune / epidemics are uncommon. Improving sanitary conditions  many young adults susceptible -- increase frequency of outbreaks. Children play important role in HAV transmission/ most of cases are asymptomatic or unrecognized. In areas in Southeast Asia 90% have serological evidence of past infection compared to 33% in USA.

  4. In developed countries epidemics are usually of the propagated type (evolve slowly, over wide area, and for many months) ; common source epidemic may evolve rapidly. Mode of transmission: a. Mostly through oral-fecal route. Common source epidemic at community level is through contaminated: - water - food by food handlers or - produce before entering the food chain. b. IV drug users and hemophiliacs outbreaks confirmed the needle-borne transmission

  5. Methods of control: A. preventive measures Educate the public on good sanitation Provide water treatment and distribution system & sewage disposal system Vaccine: inactivated vaccine proved to be safe and effective Not for children under 1 year of age 2 doses required Protection appear in 14-30 days after first dose; 2nd dose is given for long time protection. In high endemic areas it may be cost effective to screen for HAV before vaccination.

  6. Immunization In Developed countries vaccination of high risk groups: persons at increased risk for HAV infection : - chronic liver disease and clotting disorders - homosexuals - Iv drug users - travelers to endemic areas (could be given with IG if travel in <2weeks) children in communities with consistently elevated rates of hepatitis A. IG to Close personal contacts (household, sexual, institutional) of persons with HAV is recommended as early after exposure as possible. - Could be given with the vaccine on separate sites

  7. Passive immunization (IG): - When administered before exposure or during the early IP, it is effective in preventing clinical hepatitis A. B. Control of patient & contacts a. Report the disease to local health authority b. Isolation of confirmed cases/ enteric precautions for 1 week post jaundice; but longer in outbreaks in neonatal ICU. c. Concurrent disinfection: Sanitary disposal of feces, urine, and blood d. Immunize contacts (vaccine & IG within 2 weeks post exposure) after serology confirmation of HAV infection in index patients (IGM anti-HAV testing).

  8. Hepatitis B virus (HBV)

  9. Epidemiology • About 10% of children and 30-50% of adults with acute HBV infection show icteric disease. • Case fatality is 1%, higher in >40 y. • Chronic infection is found in 0.5% of adults in North America and 0.1-20% in other parts of the world. • After acute infection, the risk of chronic infection (CI) is inversely related to age. • CI occurs among 90% of infants infected at birth, • 20-50% of children infected between 1-5 years, and • 1-10% infected of older children and adults.

  10. 15-25% of CI patients will die prematurely of cirrhosis or hepatocellular carcinoma (HC). • HBV may be the cause of 80% of all cases of HC worldwide. • The risk of HBV infected men transmitting it to women is 3 times more than it is women to men.

  11. Occurance • Worldwide and endemic • 2 billions persons have been infected with 350 millions chronically infected • Each year 1 million persons die of HBV and 4 million acute clinical cases occur. • In highly endemic countries (HBsAg >8%), most infections occur during infancy and early childhood. • In intermediate endemic countries (HBsAg 2-7%) infection occur in all age groups. • In Low endemic countries, infections is more among young adults; especially high risk groups.

  12. Mode of Transmission Body substances (blood/products, saliva, semen, vag. secretions, unfixed tissues, CSF, pleural/peritoneal/pericardial/synovial/ amniotic fluids transmitted through percutaneous (IV, IM, SC, Intradermal) or permucosal route Inanimate objects (HBV stable for 1 week at room tempreture).

  13. Major modes of transmission: • Anal intercourse, • In household, HBV transmitted from child to child. • Sharing razors and toothbrushes. • Perinatal transmission is common (85% of babies born to mothers positive for HBsAg). • Injecting drug users • Nosocomial exposure such as : transfusion of blood/blood products, hemodialysis, acupuncture, needle stick. • IG, heat treated plasma protein, albumin, and fibrinolysin are safe.

  14. Methods of control • Preventive measures. 1. Vaccine: one from plasma of HBsAg +ve, 2nd from recombinant DNA (rDNA). Combined passive-active immunoprophylaxix is more effective but expensive. • In all countries, routine infant immunization should be the primary strategy to prevent HBV infection. • In endemic countries, routine infant immunization rapidly eliminates transmission. • For low/ intermediate endemicity countries immunization extended for older children, adolescents, and adults may be more desirable strategy.

  15. Strategies that ensure high vaccine coverage of successive age group cohorts are the most effective in eliminating HBV transmission. • In addition, immunization strategies can be targeted to high risk groups, which account for most cases among adolescents and adults. • Testing to exclude people with pre-existing anti-HBs or anti-HBc is not requiredbut may be a cost saving method among children and adults where level of infection is high. • Immunity lasts fro 15 years.

  16. Pregnancy is not a contraindication for giving vaccine. • Vaccine schedule vary by country. What is in Jordan? Single antigen preservative-free HB vaccine is now available. • The current WHO HB prevention strategies based on routine universal newborn/infant immunization. The greatest fall in incidence of HB is in countries with high vaccine coverage at birth and infancy. 17

  17. Persons at high risk should routinely receive pre-exposure HB immunization include: a. people recently acquired STDs and people have history of > 1 sexual partner in the past 6 months; b. men have sex with men; c. sexual partners and household contacts of HBsAg +ve persons; d. inmates in jails ,prisons; e. health care and public safety workers involved in handling blood/body fluids; f. Hemodialysis; g. pts with bleeding disorders receiving blood; h. travelers intend to spend >6moths in countries of high rate of CI (>2%) and will have close contact with local people. 18

  18. Adequately sterilize all syringes (use disposables ). • In blood banks, all blood tested for HBsAg. • Reject donors with history of viral hepatitis, drug injection, receive blood or tattooing in the last 6 months. • Maintain surveillance for all cases of posttransfusion hepatitis. • Health care workers are not to perform surgery or similar treatments for patients. 19

  19. B. Control of patient, contacts and the immediate environment. • Report, class 2. • Isolation: universal precautions against blood/products. • Concurrent disinfection: of equipment contaminated • Quarantine: NA • Immunization of contacts • Infants of mothers with HBsAg +ve to be given single dose of vaccine within 12 hours of birth, and where available .5 ml HBIG at separate site, 2nd and 3rd doses at 1-2 and 6 months later. • Investigation of contacts 20

  20. Hepatitis C virus (HCV) 21

  21. Epidemiology Occurrence • Worldwide distribution directly related to prevalence of persons sharing injection equipment and to prevalence of poor parenteral practices in health settings. • WHO estimate 130-170 million (2-3%) of world population are chronically infected. Most regions anti-HCV prevalence is <2.5%, but 2.5-4.9% in western pacific, and 1-12% in middle east. • HCV accounts for 40% of chronic liver disease. 22

  22. Mode of Transmission • Primarily parenteral but sexual and mother-to-child has been documented • 1970s 10% per chronically infused patients receiving screened blood developed hepatitis. • 1980s with HIV screening this figure dropped to 5%. • 1980-1990 HCV was discovered and thus figure dropped even further due to testing for anti HCV. • Discovery of 2nd generation of anti HBc assays (automated PCR testing for HCV RNA) reduced infection to 1/100,000. • HBC can be transmitted by other percutaneous routes, drug users. • HBC can be transmitted by occupational exposure to blood and tend to increase in hemodialysis units. 23

  23. Sexual and perinatal mode is theoretically valid but not sufficient enough (account for 5% of all cases). • Infection of HCW is like general population. • No infection from breast feeding. • No infection to household contacts. 24

  24. Methods of control Preventive measure General control measures against HBV apply IG is not effective No vaccine is yet developed strict measures of screening donated blood Counseling with high risk groups including health care workers. 2. Control of patient, contacts, and immediate environment General control measures against HBV apply 25