title: Hepatitis E viral loads in plasma pools for fractionation.
abstract: BACKGROUND
  It is now recognized that blood donors may be silently infected with hepatitis E virus (HEV) and that plasma pools used in the manufacture of plasma-derived medicinal products may also contain detectable virus RNA. The occurrence of HEV-infected blood and plasma donors can vary considerably depending on local epidemiology.
  
  
  METHODS
  Manufacturing plasma pools from North America, Europe, the Middle East, and Asia were examined for the presence of HEV using transcription-mediated amplification of HEV RNA; confirmatory testing was performed using real-time reverse transcription polymerase chain reaction and sequencing.
  
  
  RESULTS
  A total of 484 pools were tested. Asian pools were most frequently positive for HEV RNA and had higher viral loads, although none exceeding 300 IU/mL, and the sequenced strains (n = 5) clustered with Genotype 4, including one significantly divergent sequence. Only HEV Genotype 3 was identified in North American (n = 5) and European (n = 5) pools. There was no evidence of HEV in any pools tested from the Middle East.
  
  
  CONCLUSIONS
  HEV was detected in manufacturing plasma pools from three different continents; viral loads were low-consistent with large pool sizes and moderate levels of HEV viremia at the individual donation level-but are nevertheless informative for risk assessment of plasma-derived medicinal products. Where sequencing was possible, analysis confirmed the presence of viruses consistent with locally circulating genotypes in the respective regions. The absence of HEV in Middle Eastern pools is consistent with the low prevalence of HEV in this region, likely due to low pork consumption.
authors.affiliation: Paul-Ehrlich-Institut, Langen, Germany. Sally.Baylis@pei.de.
authors.forename: Sally A
authors.initials: SA
authors.lastname: Baylis
authors.affiliation: Institute of Virology, University of Bonn Medical Centre, and the German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Corman
authors.affiliation: Hologic, Inc, San Diego, California.
authors.forename: Edgar
authors.initials: E
authors.lastname: Ong
authors.affiliation: Hologic, Inc, San Diego, California.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Linnen
authors.affiliation: Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: C Micha
authors.initials: CM
authors.lastname: Nübling
authors.affiliation: Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Blümel
mesh_terms: D001208:Asia / Q000453:epidemiology; D001782:Blood Donors; D005060:Europe / Q000453:epidemiology; D005838:Genotype; D016751:Hepatitis E / Q000453:epidemiology; D016752:Hepatitis E virus / Q000235:genetics*; D006801:Humans; D009656:North America / Q000453:epidemiology; D010949:Plasma / Q000821:virology*; D015995:Prevalence; D012367:RNA, Viral / Q000097:blood; D017423:Sequence Analysis, RNA; D019562:Viral Load; D014766:Viremia
chemical_list: D012367:RNA, Viral