Human Bocavirus in Children with Acute Gastroenteritis, Chile, 1985–2010

Jorge Levican, Esteban Navas, Joaquín Orizola, Luis Fidel Avendaño, and Aldo Gaggero

Author affiliations: Universidad de Chile, Santiago, Chile

Abstract

We detected human bocavirus in 89 (19.3%) of 462 fecal samples collected during 3 periods from 1985 through 2010 from children <5 acute="" age="" bocavirus="" chile.="" chile="" circulation="" confirm="" findings="" gastroenteritis.="" hospitalized="" human="" in="" long-term="" of="" our="" p="" the="" were="" who="" with="" years="">

Human bocavirus (HBoV) was discovered in 2005 on the basis of large-scale molecular virus screening of respiratory samples (1). More recently, HBoV was detected in fecal samples of children who had gastroenteritis with or without symptoms of respiratory infection and in samples from healthy controls (2–4). Although HBoV is assumed to have coexisted with humans for a long time, there is little evidence to confirm long-term circulation.

The Study

We analyzed 462 fecal specimens from hospitalized children 0–60 months of age (median 13.8 months) with acute gastroenteritis in Chile. The samples belonged to a collection obtained from 1985 through 2010. Three periods were analyzed: 1985–1986 (period A, 86 samples), 1997–2004 (period B, 261 samples), and 2009–2010 (period C, 115 samples) (Table). The patients did not show respiratory symptoms during their clinical evaluation. Analysis for rotavirus, calicivirus, enteric adenovirus, and astrovirus was conducted (data not shown), and only samples negative for these viruses were selected. The samples were maintained at −80°C until analysis.
DNA from fecal samples was extracted by using a High Pure Nucleic Acid Viral Kit (Roche Diagnostics, Indianapolis, IN, USA) following the manufacturer’s instructions. Using PCR with specific primers as described, we performed the HBoV detection (3–5). Positive and negative controls were included in each amplification round. PCR products were purified, and nucleotide sequences were determined by Macrogen Inc. (Seoul, South Korea) and submitted to GenBank (accession nos. KC757418–KC757460).
Phylogenetic relationships between isolates from Chile and GenBank reference strains were studied by using MEGA5 software (6). We inferred the evolutionary history using the neighbor-joining method. Bootstrap (1,000 replications) was used to assess the reliability of individual nodes in each phylogenetic tree. Evolutionary distances were computed by using the Kimura 2-parameter method (6). Variance analysis of the bocavirus detection frequency was conducted by using the Kruskal-Wallis test (α = 0.05) using Statdisk 12.0.1 software (Marc Triola and Pearson Education, Inc., New York, NY, USA). The Ethics Committee of the Faculty of Medicine, University of Chile approved the study.
The 89 (19.3%) samples positive for HBoV were distributed throughout the study period; 22.1%, 21.1%, and 13.0% for periods A, B, and C, respectively (Table). HBoV1 was the most frequently detected species, with 65 (14.1%) cases, followed by HBoV2 and HBoV3, with 18 (3.9%) and 6 (1.3%), cases, respectively (Table). HBoV4 was not detected.