Microbiology Unit 5

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Microbiology Unit 5
2010-11-03 13:35:07

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  1. Hepatitis A
    General Info
    • most common viral infection
    • aka HAV or infectious hepatitis
    • HAV is very resistant to surface disinfection, can remain on fomite up to 3 weeks
    • No carrier state as there is a complete recovery
  2. HAV transmission
    fecal-oral route often from eating contaminated food or water, raw oysters or food service workers with poor hygiene
  3. HAV Symptoms
    • jaundice, RUQ pain, liver function impairment
    • incubation is 2-4 weeks (shortest)
  4. HAV Diagnosis
    • liver function tests includes AST and ALT (which indicates liver damage)
    • Hepatitis A antibodies (IgM-acute and IgG persist indefinitely)
  5. HAV Treatment and Prevention
    • vaccines available for babies
    • vaccines available for adult, 2 doses, lasts 10 years
    • give Hepatitis Immune globulin if there is a known exposure
    • HAV is very resistant to surface disinfection, can remain on fomite up to 3 weeks.
    • No carrier state as there is a complete recovery
  6. Hepatitis B
    General Info
    • aka serum hepatitis or HBV
    • about 10% will complicate as Chronic Active Hepatitis B
  7. HBV Transmission
    • Heterosexual sex is most common
    • IV, percutaneous (tattoos, body piercing, dialysis)
    • homosexual sex especially in males
    • IV drug using (sharing males)
    • perinatal - babies can get this via vaginal birth
    • blood transfusion - small risk if donor is in the window period because the virus is circulating early in infection; blood test are negative as there is not enough antibody to detect
  8. HBV Symptoms
    • jaundice, RUQ pain, liver function impairment
    • about 10% will complicate to Chronic Active Hepatitis B -- which will continuously destroy liver cells and often death; liver cancer is also common as DNA is altered
    • chronic infection is very common in babies born with HBV
    • can persist for years - carrier state
  9. HBV Diagnosis
    • Blood tests: HbsAg, HbcAg, and HBsAb
    • HbsAg is Hepatitis B Surface antigen that detects the outter shell of the virus; for acute HBV, the results will be positive
    • HbcAg is the Hepatitis B Core antigen that detects the core of the virus; this is positive after 4-6 weeks after the surface is positive
    • HBsAb is the Hepatitis B antibody
  10. HBV Treatment
    • for chronic cases - alpha interferon (Intron A) and Lamivudine (base analog inhibitor)
    • these are used to control viral replication but liver function will still decrease
  11. Hepatitis C
    General Info
    • aka HCV or non-A, non-B hepatitis or post-transfusion hepatitis
    • 4 millions Americans infected
    • at least 35,000 new cases every year
  12. HCV Transmission
    • blood and body fluid transmission
    • IV drug use
    • tattoos
    • body piercing most common means of transmission now
    • occasional perinatal, sexual, health care associated infections
    • transfusion is minimal risk
  13. HCV Symptoms
    • "silent epidemic" as most cases are asymptomatic or mild (80% have no symptom)
    • chronic infection in 75-85% of the population
    • destroys liver function
    • most common reason for liver transplant
  14. HCV Diagnosis
    • lab testing available since 1994
    • home testing is available
    • minimal risk from blood transfusions
  15. HCV Prevention and Treatment
    • treatment: interferon + ribavirin for chronic infection
    • no effective treatment for acute infection
    • prevention: no vaccine available, screen blood supply and only use licensed US tattoo parlors
  16. Hepatitis D
    General Info
    • aka HDV or Delta hepatitis
    • viral fragments - consists of RNA fragments and delta antigen, not whole virus
    • "piggy back" virus with HBV
  17. HDV Transmission
    • coinfects with HBV
    • blood and body fluid transmission
  18. HDV Symptoms
    • double infection is more severe than HBV alone
    • chronic infection may occur
  19. HDV Diagnosis
    test for HDV antibodies (IgM, IgG) since 1995
  20. HDV Prevention
    Vaccine with HBV
  21. Hepatitis E
    • aka HEV
    • outbreaks in China due eating pig
  22. Hepatitis E Transmission
    • fecal-oral route
    • waterborne epidemics in developing countries
    • found in pigs also
  23. HEV Symptoms
    • seen mostly in children and young adults
    • mild disease if not pregnant
    • if pregnant, can cause liver failure with 30% mortality rate and with fetal demise
    • no carrier state or chronic liver disease
  24. HEV Diagnosis
    made by symptoms, travel history to endemic areas, and exclusion of other Hepatitis
  25. Hepatitis G, GBV (GBV-A, GBV-B, and GBV-C)
    • aka non A-E hepatitis
    • in serum, 2% of US blood donors as blood supply is not tested
    • Transmission: spreads via blood and body fluids, contaminated blood products, IV drug use, sexual contact with partners
    • Symptoms: may be acute or chronic, liver failure, aplastic anemia, fatal liver disease
  26. Remember about Hepatitis
    • Liver cancer is B, C, D, G, GBV
    • Fecal Oral route in A and E
    • Vaccines available in A,B
  27. Which types of hepatitis have blood borne transmission
    B, C, D, G, GBV
  28. Most strongly associated with IV drug abuse
  29. vaccines available for babies
    A and B
  30. vaccines for recommend for traveling
  31. Incubation periods
    • A - is short, 2-4 weeks
    • B - is long, 4 weeks - 6 months
    • C - is variable, 2 weeks - 6 months
  32. Most common hepatitis
  33. most endemic in developing countries
  34. Which virus piggybacks with Hepatitis B
    Describe structure and complications
    • Hepatitis D coinfects with Hepatitis B
    • it is a viral fragment, consist of RNA fragments and delta antigen
    • Symptoms are double infections, more severe than HBV
    • chronic infection is more likely
  35. Which hepatitis is associated with a high mortality rate in pregnant women
  36. Which hepatitis seen in the US that is not detected in blood supply
    G and GBV