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Full characterization of HAV RNA window period positive blood donations in Germany SoGAT XVIII Bethesda.

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Presentation on theme: "Full characterization of HAV RNA window period positive blood donations in Germany SoGAT XVIII Bethesda."— Presentation transcript:

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2 Full characterization of HAV RNA window period positive blood donations in Germany SoGAT XVIII Bethesda

3 Hepatitis A Virus Picornavirus Non-enveloped First isolated in 1979 Natural host: human Stable: heat and acid-resistant Inactivated by high temperature, formalin, chlorine Transmission: fecal-oral Replication: liver (hepatocytes) Peak viremia 10-12 days after infection Self-limited illness: asymptomatic or acute fulminant hepatitis

4 HAV Pathogenesis Incubation period of 15-50 days Prodromal illness is nonspecific Age-related severity: Children <6 years: 70% of infections are asymptomatic Older children and adults >70% of cases result in acute hepatitis with jaundice

5 HAV Recent Developments in Germany RT-PCR based tests for the presence of HAV RNA were introduced in Germany in 2000. Systems: In house Artus based technology transfer Technology: Real time RT PCR LightCyler/ABI Prism

6 HAV Kit Adaptation HAV positive blood donation (in house test) Artus/Roche negative Inhouse 4+/4- Enterovirus etc. negative Contamination/unspecific? What to do? Clinical positive (2 weeks later)

7 HAV Kit Adaptation Tests 7 real time PCRs spanning the HAV genome 6 negative 1 positive (ct 28) Long range PCR Sequencing Culture

8 HAV Kit Adaptation Real time pos.HAV Genotype III Full length pos.HAV Genotype IIIA Cell culture pos. And the Kit ??

9 HAV Kit Adaptation New Kit (with CE mark) Alignment (conserved region) Sensitivity Specificity Robustness Positive Controls Precision

10 HAV Kit Adaptation Results: New Kit (with CE mark) Alignment VP4 highest homology Sensitivity (with new primer and probes) 183 IU/ml (WHO Int. Std/Qiagen Extr.) Specificity all available strains (in vitro) 100% (HAV Ab neg.) weak crossreactivity with Enterovirus 71 Precision intra-assay 28 % inter-assay 31 % total32 %

11 HAV Kit Adaptation Results: New Kit (with CE mark) End of 2003 Kit release Detection of: 1 food associated HAV-RNA positive blood donation 4 travel related HAV-RNA positive blood donation only 1 would have been detected with the old system All Genotype I

12 HAV Kit Availabiliy 1.As IVD Worldwide 2. For blood screening LC-PCR based Systems (via Roche starting in Juli/August 2005) ABI Prism based Systems (via Abbott) Country specific restrictions may apply

13 HAV Kit Acknowledgments The German Red Cross Blood Transfusion Service of Baden Württemberg-Hessen, PCR Lab in Frankfurt The German Red Cross Blood Transfusion Center West in Hagen Blood Center of the German Red Cross NSTOB, Institute Springe Department of Virology, University of Bremen


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