title: Prospective study on Norovirus infection among allogeneic stem cell transplant recipients: prolonged viral excretion and viral RNA in the blood.
abstract: BACKGROUND
  Human caliciviruses (Norovirus and Sapovirus) are important acute gastroenteritis agents. The Norovirus (NoV) disease is usually self-limited; however, prolonged viral excretion and complications have been reported, mainly in immunosuppressed individuals.
  
  
  OBJECTIVE
  In this prospective study, we have monitored allogeneic stem cell transplant (ASCT) patients for human calicivirus infection.
  
  
  METHODS
  Ten ASCT patients were monitored for NoV and sapoviruses (SaV) infection, for a period of five months to a maximum of one year. Prolonged NoV excretion and long term viral RNA in the blood were assessed by multiplex RT-PCR targeting region C of the viral capsid. Secretor status of the patients was determined by enzyme immunoassay using Ulex Europaeus agglutinin. Partial genomic sequencing and phylogenetic analysis were performed to characterize the viral genotypes.
  
  
  RESULTS
  NoV was detected in six out of ten patients (60%). Prolonged viral excretion in feces (mean of 61.6 days) and long term presence of NoV RNA in the sera (mean of 33.6 days) of the patients were observed. SaV was not detected in any of the samples. All patients had diarrhea, vomiting and fever during NoV positivity. All NoV-positive samples were characterized as GI.3 NoV. Three Nov-infected patients presented with acute intestinal graft versus host disease.
  
  
  CONCLUSIONS
  This study brings important information on NoV course of infection in ASCT patients. It also provides evidence for long term viral RNA in the blood highlighting the importance of the inclusion of NoV screening in the routine testing performed before transplantation and during follow-up of these patients.
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil.
authors.forename: Lucianna Gonçalves Nepomuceno
authors.initials: LG
authors.lastname: Lemes
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil.
authors.forename: Thais Santos
authors.initials: TS
authors.lastname: Corrêa
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil.
authors.forename: Fabíola Souza
authors.initials: FS
authors.lastname: Fiaccadori
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil.
authors.forename: Divina das Dôres de Paula
authors.initials: Dd
authors.lastname: Cardoso
authors.affiliation: Hospital Araújo Jorge/Association for Combating Cancer in Goiás, Brazil.
authors.forename: Adriano de Moraes
authors.initials: Ade M
authors.lastname: Arantes
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil.
authors.forename: Keili Maria Cardoso
authors.initials: KM
authors.lastname: Souza
authors.affiliation: Laboratory of Virology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Brazil. Electronic address: menirasouza@gmail.com.
authors.forename: Menira
authors.initials: M
authors.lastname: Souza
mesh_terms: D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D016000:Cluster Analysis; D005260:Female; D005838:Genotype; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D029322:Norovirus / Q000302:isolation & purification*; D010802:Phylogeny; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029341:Sapovirus / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D033581:Stem Cell Transplantation; D013234:Stem Cells; D066027:Transplant Recipients; D014184:Transplantation, Homologous; D017201:Virus Shedding; D055815:Young Adult
chemical_list: D012367:RNA, Viral
keywords: Calicivirus; Norovirus excretion; Norovirus infection; Stem cell transplant; Viremia