3 Donor Selection Donor health assessment questionnaire Questions 1-13 completed by donor aloneQuestions administered orally by nurseDonor asked about ~ 85 different items related to health, medication, travel, lifestyle. Identical at each donation
4 Blood Donor Screening Donor testing HIV1/2 Antibody (Ab) and nucleic acid testing (NAT)HBV HBsAg, anti-HBcHCV Ab and NATHTLV1/2 AbWNV NATSyphilis AbCMV Ab (selected units)Chagas Ab (selective donor testing) May 2010
9 Hepatitis B DNA virus, hepadnavirus family Transmission Sexual – most commonHousehold contactPerinatal (mother to baby)Injection drug useNosocomial (needlestick injury in health care workers)
10 Hepatitis B Clinical Prevention and Treatment Incubation days (avg days)Asymptomatic in 50 – 70%Symptomatic – anorexia, nausea, vomiting, jaundiceChronic carriage in 0.1 – 20% (90% in infected infants)15 – 25% of chronic carriers develop cirrhosis or hepatocellular carcinomaPrevention and TreatmentHepatitis B vaccineHepatitis B Immune Globulin (HBIG)Treatment with antiretroviral agents, interferon (some success in chronic carriers)
11 WHO estimates more than 2 billion infected worldwide
12 Hepatitis B Markers SEROLOGICAL MARKERS Hepatitis B surface antigen (HBsAG)1Hepatitis B surface antibody (anti-HBs)2Hepatitis B core antibody (anti-HBc)1Hepatitis B core IgM (aHBcIgM)Hepatitis B e antigen (HBeAg)Hepatitis B e antibody (aHBe)VIRAL DNAHepatitis B DNA (HBV DNA)21CBS Screening test2Supplemental test
13 Hepatitis B Serological Profile Resolved Infection
14 Hepatitis C Virus capsid envelope protein protease/helicase RNA-dependentRNA polymerasec2233cc-1005’3’coreE1E2NS2NS3NS4NS5hypervariableregion777
16 Sources of Infection for Persons With Hepatitis C Injecting drug use 60%Sexual 15%Injection drug use 60%Transfusion 10%(before screening)Occupational 4%Other 1%*Unknown 10%Source: Centers for Disease Control and Prevention* Nosocomial; iatrogenic; perinatal
17 Hepatitis C - Clinical Features Incubation period: Average 6-7 wksRange 2-26 wksClinical illness (jaundice): 30-40% (20-30%)Chronic hepatitis: 70%Persistent infection: %Immunity: No protective antibody response identified888
18 Hepatitis C Virus Infection Typical Serologic Courseanti-HCVHCV antibodySymptomsTitreALTALTNormalMonths1234561Years234Time after Exposure101010
20 HIV Acquired Immunodeficiency syndrome first described in 1981 HIV-1 isolated in 1984, and HIV-2 in 1986Enveloped RNA retrovirusClinicalSeroconversion – flu-like illnesss – approx. 10% of patients, 2 – 3 wks post exposureAsymptomatic ‘latent period’ – several months to yearsAIDS related complexAIDS
21 HIV Serological Profile IgMp24 antigenENVENVGAGPOLViral loadCD4Exposurepre-antibodyInfection3 Months
22 HTLV I and II HTLV I HTLV II Caribbean, southern Japan, parts of AfricaPrevalence increases with age, 2X commoner in femalesAssociated with:adult T cell leukemia (1:500 who are seropositive, develops after 15 – 20 years)Tropical spastic paraperesisHTLV IIIVDU
23 Syphilis Primary Syphilis Primary lesion – chancre (painless) at site of innoculationSecondary or Disseminated SyphilisRash - Macular, maculopapular, papular or pustularLatent SyphilisEarly latentLate latentLate or Tertiary SyphilisNeurosyphilis – asymptomatic or symptomatic (delusions, hallucinations, personality change, seizures, ataxia)Cardiovascular syphilis – aortic aneurysmGummatous syphilis – skin, bone, mucous membranesSyphilis (bacteria) spirochaetes byImmunoflourescence
26 Screen Testing vs Confirmatory Testing Screen Tests are designed to be highly sensitivegoal is to not miss any positiveshoweverfalse reactive results can occur even when the donor was never exposed to the particular infectionConfirmatory Testing is highly specificThis is used for :Donor counsellingReporting to public healthInitiating LookbackDonors are deferred based on screening test results.26
27 Confirmatory Testing HIV-1 Western Blot Individual proteins of HIV-1 lysate separated according to size by polyacrylamide gel electrophoresis.The viral proteins are then transferred onto nitrocellulose paper and reacted with the donor’s sample.The results are:NEGATIVE (no bands present),INDETERMINATE (any bands present but pattern does not meet criteria of positive)POSITIVE (must have two or more of bands at p24, gp41 and gp120/160) based on the pattern which is present.Western Blot also used for HIV-2, HTLVI/II27
29 Confirmatory and Supplemental Testing Hepatitis B HBsAg Neutralizationconfirms the presence of HBsAg by means of specific antibody neutralization.Anti-HBsEIA for the qualitative and quantitative detection of antibodies to the Hepatitis B surface antigen.HBV DNAqualitative test for the direct detection of HBV using PCR methodology29
30 Confirmatory Testing HCV Qualitative immunoblot assay - RIBA.Utilizes recombinant HCV encoded antigens and synthetic HCV encoded peptides that are immobilized as individual bands onto test strips.The possible serological profiles defined by this assay include the following: Negative, Positive, Indeterminate30
32 Confirmatory Testing Syphilis Repeat reactive samples are referred to the Public Health Laboratory (Alberta or Ontario) for confirmatory testing.EIA screening test, followed by:Flourescent Treponemal Antibody-Absorbed (FTA- ABS)Western BlotMicroHAemagglutination-Treponema Pallidum (MHA- TP)32
40 Future Alternate Algorithms Use of HCV and HIV-1 NAT in confirmatory algorithm:Already being performed as a screening test for all donationsNAT results integrated into donor counsellingSensitivity and specificity is high relative to confirmatory assays used even though NAT is performed in poolsFor NAT positive donor samples, HCV RIBA or HIV-1 WB is not needed.Revised screening strategy for anti-HBc:Algorithm has been changed to a one strike algorithm the same as for other TD markers ( Jan aHBc positive donors were allowed to return to donate as long as not aHBs or HBV DNA positive)40
41 West Nile Virus Transmission Cycle Mosquito vectorIncidental infectionsWest NilevirusWest NilevirusIncidental infectionsBirdreservoir hosts
42 West Nile Infection - Clinical Incubation daysAsymptomatic or mild febrile illness + rashElderly often more severely ill with encephalitis:Headache, stiff neck, nausea, vomitingAltered level of consciousness, profound muscle weaknessCSF shows pleocytosis, elevated protein, normal glucose
43 West Nile Virus Transmission by organ transplantation and blood transfusion 1st reported case of WNV transmission in U.S. by organ donation August 2002 – 2 kidney, 1heart, 1 liver recipients infected23 patients confirmed to have acquired WNV infection via RBCs, platelets, FFP in 20025 cases of reported WNV in Canada (2002) had received blood transfusion within 28 days: Total 4 probable cases of TT-WNV43
44 Strategy for Single Unit Testing 2005 - 2009 CBS began screening for WNV in blood donors using a Roche WNV NAT assay in 2003 by mini-pool (6)Single unit testing was initiated in 2004 to enhance sensitivity in areas of WNV activity:SUT initiated in a health region when one WNV positive donor is identified,orThe number of new confirmed community cases reported in a health region reaches the level of 1/1,000 (rural areas) or 1/2,500 (urban) for the past 2 consecutive weeks.SUT discontinued if no more positive donors or # of community cases fall below population triggerSUT discontinued after 14 days2006 – 2009 SUT discontinued after 7 days44
45 WNV NAT Screen Reactive Donors by Province (to Jun. 1 2007- Oct Total Positive DonorsBC/Yukon31,2Alberta41Saskatchewan401Manitoba211,3Ontario2TOTAL711 1 false positive donor (alt. NAT and antibody negative)22 donors with travel history31 positive donor in Winnipeg45
47 Chagas Disease – What is it? Infection caused by a protozoan parasite, spread by triatomine bugs endemic to Central & South America, MexicoEstimated that million people are infected~50,000 people die annually from ChagasAlso spread by blood transfusion, organ transplants, rarely mother-child (transplacental),47
53 Stages of Chagas Disease Acute stage: Immediate reaction to infectionOnly occurs in about 1% of people infectedSwelling of the eye, tiredness, fever, rash, loss of appetiteCan be fatal for infants and very young childrenSevere in immunocompromised recipients (HIV/AIDS, transplants)Responds to Nifurtimox or BenzonidazoleChronic: 10 to 20 years after infectionEnlarged heart, arrythmias, cardiac failure (20-30%) or digestive tract – megacolon, megaesophagus (9-14%)Chronic encephalitis40-50% parasitemic with no symptomatic disease
55 Reported cases of T. cruzi transmission via transfusion in the U. S Reported cases of T. cruzi transmission via transfusion in the U.S. and Canada1987 California via Mexican donor1989 New York City via Bolivian donor1989 Manitoba via Paraguayan donor1993 Houston via unknown donor1999 Miami via Chilean donor2000 Manitoba via German/Paraguayan donor2002 Rhode Island via Bolivian donor5 cases – platelet transfusion, others unknownHeadline same comments; font size; ORTHO® T. cruzi (italics) Test System **Under developmentTrypanosoma cruzi (italics)Add Mantoba via Paraguayan donorReference Source: Dr. D. Leiby, ARC5555
56 AABB Chagas' Biovigilance Network Continental U.S. Map: Cumulative RIPA Positives (January 2007 to present) (updated 2/18/10)AABB Chagas' Biovigilance Network
57 CBS Response To Chagas Disease Phase 1 - Risk Questions added to the Record of Donation Feb.9, 2009 1. Were you born in Mexico, Central America, or South America?2. Was your mother or grandmother born in Mexico, Central America, or South America?(If the answer is yes, the nurse would determine if it was the mother or maternal grandmother, leading to Chagas' risk, or the paternal grandmother, with no Chagas' risk)3. Have you spent 6 months or more at any one time in Mexico, Central America, or South America?Outcome for DonorsPlatelets and transfusible plasma are not made from donors who answer ‘yes’ to any of the risk questions.
58 CBS Response to Chagas Disease Phase 2 - Donor Testing - May 2010 Implement donor testing as a mandatory screening test for those donors answering yes to risk questions.Testing performed in Toronto Donor Testing Lab – batched.Repeat reactives (RR) will be tested by immunoblot (confirmatory assay) at National Testing Lab in Ottawa or by National Parasitology Reference lab at McGill.Donors permanently deferred based on a RR test.All manufactured components destroyed based on RR result.Lookback performed on all confirmed positive donors.Platelets will not be made from donors who answer yes to risk questions even if they test negative (issue with timing).
60 Babesiosis Protozoan parasites Babesia microti, duncani, in N. Am. Ixodes scapularis/ Ixodes pacificus (deer tick, blacklegged tick)Same tick vector as for Lyme Disease and Anaplasmosis)In Europe. I. racinus (sheep tick) is primary Babesia vector2 yr life cycleAdult ticks-adult female ticks feed and mate on large animals esp white tailed deer, (but sometimes humans) in the fall or early spring. The female lays her eggs in spring, then dies. Adult females infected with disease agents as larvae or nymphs may transmit disease during this feeding. They are slow feeders and will feed for 3-5 days.Male ticks attach, but do not feed or become engorged. Larval ticksMay - September, eggs hatch into larvaethe size of a period at end of sentenceinitially does not carry diseases (i.e Lyme disease, anaplasmosis, babesiosis) may pick up diseases during its first meal from a diseased host (usually white-footed mice or other small mammal) and be able to transmit the disease(s) during its second or third feeding.After this feeding, the larvae molt into nymphs and become dormant until the following spring.Nymph ticksMay through August of 2nd yr, nymph becomes active and takes its second feeding (usually white footed mouse).If the tick is carrying disease agents from its first feeding in the larval stage, it can transmit them during this second feeding; THIS IS MAIN TIME OF TX TO HUMANS. If the nymph was not already infected, it can become infected if the second meal host is carrying disease agents. In the fall of the second year, nymphs molt into adult ticks.Nymph stage ticks often look like a speck of dirt or a freckle on a person’s skin.
61 Epidemiology Sporadic cases in Europe and Asia U.S. Cases reported in: ConnecticutRhode Is.New York StateCaliforniaWashington StateMississippiKentuckyMinnesotaWisconsin
62 Clinical Most infections asymptomatic or unrecognized Incubation1-6wks.(9 post transfusion)Flu like symptomsSevere: hemolytic anemia, thrombocytopenia, renal failure, ARDSOverall mortality~5% (higher if at-risk)i.e. immunocompromised, asplenics, v. young and old, co-infection with other tick-borne diseasesTreatmentClindamycin + quinine x 7 dAtovoquone + azithromycinAsymptomatic carrier state for months – yearsup to 50% of seropositive cases may be parasitemicInnate immunity (NK cells, macrophages) and cell mediated immunity (Th cells) and assoc cytokines TNFα & INFγ) important in suppressing parasitemia
63 Transfusion Transmitted Babesiosis >70 cases reported since 1979, most in U.S.1 Canadian report, 1999Associated with donor travel to Cape CodExtracellular and intra-erythrocytic forms,one of which is vacuolated.
64 Next Steps Better characterize donor risk of Babesiosis Seroprevalence surveystick surveys (Ixodes species and Babesia prevalence)Assess donor risk of exposureSpecificity difficult because:Exposure common in endemic areasEndemic areas are changing with climate and ecology changeDonors and blood move aroundDevelop sensitive, specific laboratory donor screening assaysSelective vs universal donor screening?Routine vs periodic or seasonal screening?Serologic vs nucleic acid testing(NAT)?