The role of human bocavirus as an agent of community-acquired pneumonia in children under 5 years of age in Fortaleza, Ceará (Northeast Brazil)

Abstract

The human bocavirus (HBoV) is an agent of upper and lower respiratory infections, affecting mainly children under 5 years of age. Community-acquired pneumonia (CAP) is an important public health problem in developing countries, representing one of the main causes of hospitalizations and deaths in children. The aim of this study was to describe the prevalence of HBoV and the clinical and epidemiological characteristics in children diagnosed with CAP. For this purpose, nasopharyngeal aspirates were collected from 545 children aged 0 to 60 months diagnosed with CAP between January 2013 and December 2014 in a reference pediatric hospital in Fortaleza, Ceará, Brazil. The samples were subjected to PCR for detection of HBoV and parainfluenza 4 (PIV4) and indirect immunofluorescence for detection of respiratory syncytial virus (RSV), adenovirus (AdV), influenza A and B (FLU A and FLU B), and parainfluenza 1, 2, and 3 (PIV1, PIV2, PIV3). Clinically, most CAP were non-complicated (487/545; 89.3%); however, 10.7% (58/545) of children were treated in the ICU/resuscitation sector. Among the total samples analyzed, 359 (65.8%) were positive for at least one virus surveyed and 105 (19.2%) samples had two or more viruses. HBoV was detected in 87 samples (15.9%), being the second most prevalent virus. RSV, AdV, FLU A, FLU B, and PIV 1-3 were detected in 150 (27.5%), 45 (8.2%), 30 (5.5%), 3 (0.5%), and 131 (24%) samples, respectively. The age average was 12.1 months in children infected with HBoV, and the most frequent symptoms were dyspnea and cough. In addition, 90.6% of HboV-positive children received antibiotics as empirical treatment. HBoV did not show any circulation pattern; however, it seemed to be more frequent in the first half of the year, totaling 68.9% of the cases. HBoV is a frequent agent of pneumonia in the child population studied.

Keywords: Children; Community-acquired pneumonia; Epidemiology; Human bocavirus; Respiratory viruses; Viral pneumonia.

Fig. 1

Number of virus detections in children diagnosed with pneumonia, considering single infections and coinfections, by conventional PCR and indirect immunofluorescence assay. HBoV = human bocavirus; RSV = respiratory syncytial virus; AdV = adenovirus; PIV1 = parainfluenza virus 1; PIV2 = parainfluenza virus 2; PIV3 = parainfluenza virus 3; PIV4 = parainfluenza virus 4; FLUA = influenza A; FLUB = influenza B

Fig. 2

Number of virus coinfections detected in children diagnosed with pneumonia by conventional PCR and indirect immunofluorescence assay. HBoV = human bocavirus; RSV = respiratory syncytial virus; AdV = adenovirus; PIV1 = parainfluenza virus 1; PIV2 = parainfluenza virus 2; PIV3 = parainfluenza virus 3; PIV4 = parainfluenza virus 4; FLUA = influenza A; FLUB = influenza B

Fig. 3

Distribution of the studied viruses during the 24-month period. A Occurrence of pneumonia cases (bold line) and rainfall in millimeters (dashed line). Monthly occurrence of B human bocavirus; C respiratory syncytial virus; D adenovirus, E parainfluenza 1 (black bars) and parainfluenza 2 (gray bars); F parainfluenza 3 (black bars) and parainfluenza 4 (gray bars); G influenza A (black bars) and influenza B (gray bar). y-axis represents number of cases, x-axis represents months (2013–2014)