Showing papers by "Filemon Bucardo published in 2007"

Mutated G4P[8] rotavirus associated with a nationwide outbreak of gastroenteritis in Nicaragua in 2005.

Abstract: During February and March 2005, one of the largest national recorded outbreaks of severe acute gastroenteritis occurred in Nicaragua, affecting ≥64,000 individuals and causing ≥56 deaths, predominantly in children under 5 years of age. Through a nationwide laboratory-based study, stool samples were collected and investigated for rotavirus. Of 108 stool samples examined, 72 (67%) were positive for rotavirus. While 69% (50/72) of the positive samples were found in children less than 2 years of age, 50% (6/12) of the adult samples were positive. A mutated G4P[8] strain was the most commonly recognized strain (85%), followed by mixed G strains (8%) and G9P[8] (7%) strains. Phylogenetic analysis of the VP7 gene revealed that the G4 strains belonged to the emerging lineage Ic and was distantly related to the ST3 and VA70 G4 strains. Secondary structure predictions of the VP7 G4 protein revealed an insert of an asparagine residue in position 76, which, combined with additional mutations, surprisingly modified two downstream β-sheets at amino acid positions 80 to 85 and 115 to 119. The 2005 G4P[8] strain compared to a G4P[8] strain from 2002 had a substitution of an asparagine residue for threonine (Asn→Thr) at position 96 within antigenic region A, thus eliminating a potential glycosylation site. The mutated G4 virus was introduced in Nicaragua after 2002 and probably emerged from Brazil, Argentina, or Uruguay.

Novel LUX™ Real-time PCR Assays for Detection and Quantification of Genogroups I and II Noroviruses in Clinical Specimens

Abstract: 2 3 Norovirus is now recognized as the leading cause of nonbacterial, acute gastroenteritis in 4 adults causing numerous outbreaks worldwide We have developed two novel Light Upon 5 Extension™ (LUX™) real-time PCR assays for detection and quantification of norovirus 6 genogroups I and II The LUX™ system uses a fluorophore attached to one primer having a 7 self-quenching hairpin structure making it cost-effective and specific The assays were 8 evaluated against clinical stool specimens (n=103) from Sweden and Nicaragua and compared 9 to established methods The norovirus assay detected more positive stool specimens (47/103) 10 than conventional PCR (39/103) and corresponded to a TaqMan® real-time PCR with the 11 exception of one specimen Furthermore, the assays correctly identified all (n=11) coded 12 control specimens in a reference panel containing various genogroups and genotypes Both 13 LUX™ real-time PCR assays had a wide dynamic range, detecting from ≤10