Transfusion Related Hepatitis A and B

Cards (75)

  • before 1984, used to screen blood for Hepatitis B and syphilis
  • Adding donor interviews and doing volunteer only donations, plus better testing methods, have greatly reduced the risks of acquiring infections from blood transfusions
  • a large percentage of transfusion transmitted complications have a viral etiology
  • viruses are intracellular organisms, which use the host to reproduce
  • the transmission of viruses can be associated with cellular components or plasma
  • any blood product made from pooled plasma is more likely to transmit viruses
  • the hepatitis viruses attack the liver
  • there are 6 classes of primary hepatitis viruses (A-G), but the ones we are concerned with are A, B, C
  • secondary hepatitis viruses involve the liver secondary to another infection (EBV, CMV, etc)
  • all hepatitis viruses can be transmitted through blood products
  • only products that are specially treated to deactivate virus can viruses not transmit (e.g. plasma protein fraction)
  • the risk of hepatitis viral transmission via blood products is greatly reduced: HCV transmission is 1 in 1.1 million units; HBV is about 1 in 1.2 million units
  • the first hepatitis A epidemic was in the 17th century; it was discovered that it is shed through the stool
  • hepatitis A is a small, RNA, simple, nonenveloped virus with a nucleocapsid
  • 40-45% of adults have evidence of prior exposure to hepatitis A, usually follows fecal-oral route
  • hepatitis A is transmitted via contaminated food and water; or person-to-person, especially when poor hygein is involved (day-care centers are prone to outbreaks)
  • risks of hep A: living in areas with poor sanitation, travel to endemic areas, people in prison, IV drug use
  • hepatitis A is rarely spread via transfusion because no chronic carrier state occurs
  • for hepatitis A transmission via blood products, donor would have to be in the 2-6 week incubation phase
  • many adults who would receive transfusion from donor with hepatitis A would have resistance due to prior exposure
  • there isn't a higher transmission rate of hepatitis A in patients who have had multiple transfusions
  • incubation for HAV is 14-45 days
  • viral replication of Hep A occurs in the liver, the virus is then excreted through the biliary system into the feces
  • in Hep A, see brief viremia (can be transmitted in transfusions in this stage of the disease)
  • symptoms of Hep A: nausea, vomiting, loss of appetite, malaise, diarrhea; jaundice is often present
  • we can use hepatitis A markers to ID current or past infections
  • if HAV is suspected, test for IgM antibodies to the virus
  • If there is no IgM, but you find IgG, indicates old infection
  • routine antibody screenings for HAV is not done
  • donor interview questions are designed to pick up symptoms that may indicate HAV infection
  • if HAV is discovered after the fact, can give recipient serum immune globulin which will decrease symptoms
  • Travelers to endemic places should get a HAV vaccination
  • HAV is seen mostly in unvaccinated, young children in resource-limited countries
  • hepatitis B was found as an antigen in Australian aborigines.  It was called the Australian antigen (Au), now it is known as Hepatitis B surface antigen (HBsAg)
  • •HBV can also be found in Peking ducks, woodchucks, and some ground squirrels
  • HBV is a double-stranded DNA virus
  • HBV's inner core contains a partially double-stranded DNA surrounded by a surface coat composed of lipid and protein
  • also in core of HBV, along with the DNA is an enzyme -- DNA polymerase
  • four genes present in HBV DNA: S, C, P, X
  • S gene: codes for the surface antigen HBsAg