Presentation is loading. Please wait.

Presentation is loading. Please wait.

Transmissible Disease Testing Canadian Blood Services Transfusion Medicine Residents March 16, 2010 Dr. Margaret Fearon & Mr. Vito Scalia 1.

Similar presentations

Presentation on theme: "Transmissible Disease Testing Canadian Blood Services Transfusion Medicine Residents March 16, 2010 Dr. Margaret Fearon & Mr. Vito Scalia 1."— Presentation transcript:

1 Transmissible Disease Testing Canadian Blood Services Transfusion Medicine Residents March 16, 2010 Dr. Margaret Fearon & Mr. Vito Scalia 1


3 Donor Selection Donor health assessment questionnaire –Questions 1-13 completed by donor alone –Questions administered orally by nurse Donor asked about ~ 85 different items related to health, medication, travel, lifestyle. Identical at each donation 3

4 Blood Donor Screening Donor testing –HIV1/2Antibody (Ab) and nucleic acid testing (NAT) –HBVHBsAg, anti-HBc –HCVAb and NAT –HTLV1/2Ab –WNVNAT –SyphilisAb –CMV Ab (selected units) –ChagasAb (selective donor testing) May

5 Confirmed TD Positive Allogeneic Donors Marker HBV HCV HIV HTLVI/II Syphilis WNV

6 Estimated Risk of Transfusion Transmitted Diseases - Residual Risk (per million donations) 95% CI HIV1: 7.8 million Hepatitis C1: 2.3 million Hepatitis B1: 153,000 HTLV1: 4.3 million 6


8 Hepatitis B Virus 8

9 Hepatitis B DNA virus, hepadnavirus family Transmission –Sexual – most common –Household contact –Perinatal (mother to baby) –Injection drug use –Nosocomial (needlestick injury in health care workers) 9

10 Hepatitis B Clinical –Incubation days (avg days) –Asymptomatic in 50 – 70% –Symptomatic – anorexia, nausea, vomiting, jaundice –Chronic carriage in 0.1 – 20% (90% in infected infants) –15 – 25% of chronic carriers develop cirrhosis or hepatocellular carcinoma Prevention and Treatment –Hepatitis B vaccine –Hepatitis B Immune Globulin (HBIG) –Treatment with antiretroviral agents, interferon (some success in chronic carriers) 10

11 WHO estimates more than 2 billion infected worldwide 11

12 Hepatitis B Markers SEROLOGICAL MARKERS Hepatitis B surface antigen (HBsAG) 1 Hepatitis B surface antibody (anti-HBs) 2 Hepatitis B core antibody (anti-HBc) 1 Hepatitis B core IgM (aHBcIgM) Hepatitis B e antigen (HBeAg) Hepatitis B e antibody (aHBe) VIRAL DNA Hepatitis B DNA (HBV DNA) 2 1 CBS Screening test 2 Supplemental test 12

13 Hepatitis B Serological Profile Resolved Infection 13

14 hypervariable region capsidenvelop e protein protease/helica se RNA- dependent RNA polymerase c22 5’ cor e E1E2NS 2 NS 3 33c NS 4 c-100 NS 5 3’ Hepatitis C Virus 14

15 15

16 Sources of Infection for Persons With Hepatitis C Sexual 15% Other 1%* Unknown 10% Injecting drug use 60% Transfusion 10% (before screening) * Nosocomial; iatrogenic; perinatal Source: Centers for Disease Control and Prevention Occupational 4% Injection drug use 60% 16

17 Incubation period:Average 6-7 wks Range 2-26 wks Clinical illness (jaundice): 30-40% (20-30%) Chronic hepatitis: 70% Persistent infection:85-100% Immunity: No protective antibody response identified Hepatitis C - Clinical Features 17

18 Symptoms anti- HCV ALT Normal Hepatitis C Virus Infection Typical Serologic Course Titre Months Years Time after Exposure 18 HCV antibody ALT

19 HIV 19

20 HIV Acquired Immunodeficiency syndrome first described in 1981 HIV-1 isolated in 1984, and HIV-2 in 1986 Enveloped RNA retrovirus Clinical –Seroconversion – flu-like illnesss – approx. 10% of patients, 2 – 3 wks post exposure –Asymptomatic ‘latent period’ – several months to years –AIDS related complex –AIDS 20

21 HIV Serological Profile IgM ENV Exposure Infection 3 Months pre-antibody p24 antigen ENV GAG POL Viral load CD4 21

22 HTLV I and II HTLV I –Caribbean, southern Japan, parts of Africa –Prevalence increases with age, 2X commoner in females –Associated with: adult T cell leukemia (1:500 who are seropositive, develops after 15 – 20 years) Tropical spastic paraperesis HTLV II –IVDU 22

23 Syphilis Primary Syphilis –Primary lesion – chancre (painless) at site of innoculation Secondary or Disseminated Syphilis –Rash - Macular, maculopapular, papular or pustular Latent Syphilis –Early latent –Late latent Late or Tertiary Syphilis –Neurosyphilis – asymptomatic or symptomatic (delusions, hallucinations, personality change, seizures, ataxia) –Cardiovascular syphilis – aortic aneurysm –Gummatous syphilis – skin, bone, mucous membranes 23 Syphilis (bacteria) spirochaetes by Immunoflourescence

24 Immune Response in Syphilis Primary Secondary Early LatentLate LatentLate Anti-lipoidal antibody Anti-treponemal IgG Anti-treponemal IgM 24


26 Screen Testing vs Confirmatory Testing Screen Tests are designed to be highly sensitive –goal is to not miss any positives however – false reactive results can occur even when the donor was never exposed to the particular infection Confirmatory Testing is highly specific This is used for : –Donor counselling –Reporting to public health –Initiating Lookback – Donors 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/II 27

28 HIV-1 Western Blot 28

29 Confirmatory and Supplemental Testing Hepatitis B  HBsAg Neutralization confirms the presence of HBsAg by means of specific antibody neutralization.  Anti-HBs EIA for the qualitative and quantitative detection of antibodies to the Hepatitis B surface antigen.  HBV DNA qualitative test for the direct detection of HBV using PCR methodology 29

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, Indeterminate 30

31 RIBA 31

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 Blot –MicroHAemagglutination-Treponema Pallidum (MHA- TP) 32


34 Anti-HIV-1/2 Confirmatory Algorithm 34

35 Anti-HCV Confirmatory Algorithm 35

36 Anti-HTLV-I/II Confirmatory Algorithm 36

37 HBsAg Confirmatory Algorithm 37

38 Anti-HBc Algorithm 38


40 Future Alternate Algorithms Use of HCV and HIV-1 NAT in confirmatory algorithm: Already being performed as a screening test for all donations NAT results integrated into donor counselling Sensitivity and specificity is high relative to confirmatory assays used even though NAT is performed in pools For 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 West Nile virus West Nile virus Mosquito vector Incidental infections Bird reservoir hosts Incidental infections

42 West Nile Infection - Clinical Incubation days Asymptomatic or mild febrile illness + rash Elderly often more severely ill with encephalitis: –Headache, stiff neck, nausea, vomiting –Altered level of consciousness, profound muscle weakness –CSF shows pleocytosis, elevated protein, normal glucose

43 West Nile Virus Transmission by organ transplantation and blood transfusion 1 st reported case of WNV transmission in U.S. by organ donation August 2002 – 2 kidney, 1heart, 1 liver recipients infected 23 patients confirmed to have acquired WNV infection via RBCs, platelets, FFP in cases of reported WNV in Canada (2002) had received blood transfusion within 28 days: Total 4 probable cases of TT-WNV 43

44 Strategy for Single Unit Testing 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, or The 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 trigger SUT discontinued after 14 days 2006 – 2009 SUT discontinued after 7 days 44

45 WNV NAT Screen Reactive Donors by Province (to Jun Oct. 15, 2009) ProvinceTotal Positive Donors BC/Yukon 3 1,2 Alberta4141 Saskatchewan40 1 Manitoba 21 1,3 Ontario2 TOTAL false positive donor (alt. NAT and antibody negative) 2 2 donors with travel history 3 1 positive donor in Winnipeg 45


47 Chagas Disease – What is it? Infection caused by a protozoan parasite, spread by triatomine bugs endemic to Central & South America, Mexico Estimated that million people are infected ~50,000 people die annually from Chagas Also spread by blood transfusion, organ transplants, rarely mother-child (transplacental), 47

48 From CDC 48

49 WHO/TDR Reduvid Bug – aka ‘Kissing Bug’ Where they like to hang out. If your Holiday Inn looks like this – move to another hotel! 49

50 Where is Chagas Disease Found? Primarily found in Latin America –Increased infections are being detected in the United States 50

51 Chagas Disease Trypanosoma cruzi n Protozoan flagellate n Trypomastigotes (blood) n Extracellular (not removed by leucoreduction) n Amastigotes multiply in smooth muscle tissue – heart, gut Amastigote in heart muscle Trypomastigotes in blood

52 26 Chagoma

53 Stages of Chagas Disease Acute stage: Immediate reaction to infection –Only occurs in about 1% of people infected –Swelling of the eye, tiredness, fever, rash, loss of appetite –Can be fatal for infants and very young children –Severe in immunocompromised recipients (HIV/AIDS, transplants) –Responds to Nifurtimox or Benzonidazole Chronic: 10 to 20 years after infection –Enlarged heart, arrythmias, cardiac failure ( 20-30%) or digestive tract – megacolon, megaesophagus ( 9-14%) –Chronic encephalitis –40-50% parasitemic with no symptomatic disease

54 WHO/TDR Cardiomegaly in Chronic Chagas Disease

55 Reported cases of T. cruzi transmission via transfusion in the U.S. and Canada California via Mexican donor New York City via Bolivian donor Manitoba via Paraguayan donor Houston via unknown donor Miami via Chilean donor Manitoba via German/Paraguayan donor Rhode Island via Bolivian donor –5 cases – platelet transfusion, others unknown Reference Source: Dr. D. Leiby, ARC 55

56 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 Questions: 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 Donors Platelets 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,

61 Epidemiology Sporadic cases in Europe and Asia U.S. Cases reported in: –Connecticut –Rhode Is. –New York State –California –Washington State –Mississippi –Kentucky –Minnesota –Wisconsin

62 Clinical Most infections asymptomatic or unrecognized Incubation1-6wks.(9 post transfusion) –Flu like symptoms –Severe: hemolytic anemia, thrombocytopenia, renal failure, ARDS Overall mortality~5% (higher if at-risk) –i.e. immunocompromised, asplenics, v. young and old, co-infection with other tick-borne diseases Treatment –Clindamycin + quinine x 7 d –Atovoquone + azithromycin Asymptomatic carrier state for months – years –up to 50% of seropositive cases may be parasitemic

63 Transfusion Transmitted Babesiosis >70 cases reported since 1979, most in U.S. 1 Canadian report, 1999 –Associated with donor travel to Cape Cod Extracellular and intra- erythrocytic forms, one of which is vacuolated.

64 Next Steps Better characterize donor risk of Babesiosis –Seroprevalence surveys –tick surveys (Ixodes species and Babesia prevalence) Assess donor risk of exposure –Specificity difficult because: Exposure common in endemic areas Endemic areas are changing with climate and ecology change Donors and blood move around Develop sensitive, specific laboratory donor screening assays –Selective vs universal donor screening? –Routine vs periodic or seasonal screening? –Serologic vs nucleic acid testing(NAT)?


Download ppt "Transmissible Disease Testing Canadian Blood Services Transfusion Medicine Residents March 16, 2010 Dr. Margaret Fearon & Mr. Vito Scalia 1."

Similar presentations

Ads by Google