Proposal for a Hepatitis A genotype panel Rob Anderson.
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Transcript of Proposal for a Hepatitis A genotype panel Rob Anderson.
![Page 1: Proposal for a Hepatitis A genotype panel Rob Anderson.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56813085550346895d966115/html5/thumbnails/1.jpg)
National Institute for Biological Standards and ControlAssuring the quality of biological medicines
Proposal for a Hepatitis A genotype panel
Rob Anderson.
![Page 2: Proposal for a Hepatitis A genotype panel Rob Anderson.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56813085550346895d966115/html5/thumbnails/2.jpg)
Hepatitis A
• Hepatitis A (HAV) is a non-enveloped, positive stranded RNA virus
• HAV is a member of the genus hepatovirus of the picornavirus family
• The genome is approximately 7.5kBp in length
• The genome has two UTRs
• The 5’ UTR is longer, being around 600-1200 BP in length, compared to that of the 3’ UTR, which is around 40-80bp.
• Like most positive sense RNA genomes, the genetic material alone is infectious
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Hepatitis A
• Nucleotide sequence analysis of HAV has allowed classification of the virus into six different genotypes
• Genotypes I, II, and III are associated with human infections whereas genotypes IV, V and VI cause infections in simians
• Subtype IA appears to be responsible for the majority of HAV cases worldwide, whereas subtype IB viruses tend to be found only in the Mediterranean region
• There is no published clinical correlation to genotype
![Page 4: Proposal for a Hepatitis A genotype panel Rob Anderson.](https://reader035.fdocuments.in/reader035/viewer/2022062719/56813085550346895d966115/html5/thumbnails/4.jpg)
Hepatitis A Disease
• Hepatitis A infection-is an acute, self-limiting infection of the liver without a chronic stage usually transmitted by the faecal-oral route
• The infection may be asymptomatic or may cause an acute hepatitis syndrome of varying degrees of severity up to and including fulminant hepatitis.
• Peak viraemia is seen 10-12 days after infection
• This means that it is possible for donations from asymptomatic individuals to occur as there is a short period (several days) between viraemia and symptoms
• Hepatitis A can be transmitted by the parenteral route but very rarely by blood and blood products
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Screening for Hepatitis A
• HAV is rarely transmitted by transfusion and is much rarer in whole blood donors than B19 (estimated to be between 1 : 500 000 - 1 000 000 donors)
• Transmission by pooled derivatives has occurred in the case of FVIII– Chudy et al. J Med Virol (1999) 57: 91-9
• Principle reason is that HAV is not inactivated during the manufacturing process and is resistant to detergent, acid (pH 1), solvents, drying, and temperatures up to 60oC
• Therefore NAT is performed for plasma intended for manufacture of blood products/derivatives
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HAV assay kits
• Two principle manufacturers of diagnostic HAV assay kits– LightCycler Hepatitis A virus quantification kit (Roche Diagnostics) – RealArt HAV LC RT PCR kit (Qiagen artus GmbH)
• Study was performed and published – G Sánchez et al. J Virol Methods (2006) 132: 160-5.
• They used HM-175 (Genotype IB) and HAS15 (genotype IA)
• Conclusion was that both assays are very suitable for detection and quantification of the most prevalent HAV subtypes
• However not all genotypes may be picked up as sensitively as each other
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27 HAV isolates with complete sequence information.
Endo et al. Virus Research 126 (2007) 116–127
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Percentage comparison of the complete ORF nucleotide and
amino acid sequence identities of 26 known HAV isolates
Endo et al. Virus Research 126 (2007) 116–127
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Proposal
• As many samples of Hepatitis A positive serum/plasma as possible covering all of the identified genotypes
• Amplification (if possible) in animals - macaques at the HPA
• NIBSC co-ordinated collaborative study to assess and validate the panel
• Genotype panel as a catalogue item analogous to the Hepatitis C panel
• The panel will be available to kit manufacturers and others intending to validate “in-house” assays for HAV