title: Detection of human bocavirus mRNA in respiratory secretions correlates with high viral load and concurrent diarrhea.
abstract: Human bocavirus (HBoV) is a parvovirus recently identified in association with acute respiratory infections (ARI). Despite its worldwide occurrence, little is known on the pathogenesis of HBoV infections. In addition, few systematic studies of HBoV in ARI have been conducted in Latin America. Therefore, in order to test whether active viral replication of human bocavirus is associated with respiratory diseases and to understand the clinical impact of this virus in patients with these diseases, we performed a 3-year retrospective hospital-based study of HBoV in outpatients and inpatients with symptoms of Acute Respiratory Infections (ARI) in Brazil. Nasopharyngeal aspirates (NPAs) from 1015 patients with respiratory symptoms were tested for HBoV DNA by PCR. All samples positive for HBoV were tested by PCR for all other respiratory viruses, had HBoV viral loads determined by quantitative real time PCR and, when possible, were tested by RT-PCR for HBoV VP1 mRNA, as evidence of active viral replication. HBoV was detected in 4.8% of patients, with annual rates of 10.0%, 3.0% and 3.0% in 2005, 2006 and 2007, respectively. The range of respiratory symptoms was similar between HBoV-positive and HBoV-negative ARI patients. However, a higher rate of diarrhea was observed in HBoV-positive patients. High HBoV viral loads (>10⁸ copies/mL) and diarrhea were significantly more frequent in patients with exclusive infection by HBoV and in patients with detection of HBoV VP1 mRNA than in patients with viral co-infection, detected in 72.9% of patients with HBoV. In summary, our data demonstrated that active HBoV replication was detected in a small percentage of patients with ARI and was correlated with concurrent diarrhea and lack of other viral co-infections.
authors.affiliation: Department of Cell Biology, University of São Paulo School of Medicine, Ribeirão Preto, São Paulo, Brazil. jlmodena@usp.br
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Proença-Modena
authors.forename: Talita Bianca
authors.initials: TB
authors.lastname: Gagliardi
authors.forename: Flávia Escremim de
authors.initials: FE
authors.lastname: Paula
authors.forename: Marisa Akiko
authors.initials: MA
authors.lastname: Iwamoto
authors.forename: Miriã Ferreira
authors.initials: MF
authors.lastname: Criado
authors.forename: Ataíde A
authors.initials: AA
authors.lastname: Camara
authors.forename: Gustavo Olszanski
authors.initials: GO
authors.lastname: Acrani
authors.forename: Otávio Augusto Leite
authors.initials: OA
authors.lastname: Cintra
authors.forename: Maria Célia
authors.initials: MC
authors.lastname: Cervi
authors.forename: Luisa Karla de Paula
authors.initials: LK
authors.lastname: Arruda
authors.forename: Eurico
authors.initials: E
authors.lastname: Arruda
mesh_terms: D000328:Adult; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003967:Diarrhea / Q000821:virology*; D005260:Female; D056661:Human bocavirus / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000821:virology*; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D012189:Retrospective Studies; D019562:Viral Load
chemical_list: D012333:RNA, Messenger; D012367:RNA, Viral