120 likes | 135 Views
This study provides a comprehensive analysis of Hepatitis A Virus (HAV) RNA in blood donations in Germany, including HAV pathogenesis, recent developments in testing technologies, and the adaptation of HAV kits. The research highlights the importance of accurate detection methods and the impact of new testing kits in improving HAV RNA detection rates. The study acknowledges the contributions of various organizations involved in the research.
E N D
Full characterization of HAV RNA window period positive blood donations in Germany SoGAT XVIII Bethesda
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
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
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
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)
HAV Kit Adaptation Tests • 7 real time PCRs spanning the HAV genome • 6 negative • 1 positive (ct 28) • Long range PCR • Sequencing • Culture
HAV Kit Adaptation • Real time pos. HAV Genotype III • Full length pos. HAV Genotype IIIA • Cell culture pos. And the Kit ??
HAV Kit Adaptation • New Kit (with CE mark) • Alignment (conserved region) • Sensitivity • Specificity • Robustness • Positive Controls • Precision
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 % • total 32 %
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
HAV Kit • Availabiliy • 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
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