Etiology and Clinical Characteristics of Single and Multiple Respiratory Virus Infections Diagnosed in Croatian Children in Two Respiratory Seasons

Abstract

The aim of this study was to determine the causative agent of acute respiratory infection (ARI) in hospitalized children, as well as investigate the characteristics of ARIs with single and multiple virus detection in two respiratory seasons. In 2010 and 2015, nasopharyngeal and pharyngeal swabs from a total of 134 children, admitted to the hospital due to ARI, were tested using multiplex PCR. Viral etiology was established in 81.3% of the patients. Coinfection with two viruses was diagnosed in 27.6% of the patients, and concurrent detection of three or more viruses was diagnosed in 12.8% of the patients. The most commonly diagnosed virus in both seasons combined was respiratory syncytial virus (RSV) (28.6%), followed by parainfluenza viruses (PIVs) types 1-3 (18.4%), rhinovirus (HRV) (14.3%), human metapneumovirus (10.1%), adenovirus (AdV) (7.1%), influenza viruses types A and B (4.8%), and coronaviruses (4.2%). In 2015, additional pathogens were investigated with the following detection rate: enterovirus (13.2%), bocavirus (HBoV) (10.5%), PIV-4 (2.6%), and parechovirus (1.3%). There were no statistical differences between single and multiple virus infection regarding patients age, localization of infection, and severity of disease (P > 0.05). AdV, HRV, HBoV, and PIVs were significantly more often detected in multiple virus infections compared to the other respiratory viruses (P < 0.001).

Figure 1

Gel image of electropherogram for (a),  (b), and (c) sets of Seeplex® RV15 OneStep ACE Detection test: (L) ladder; (1) sample negative in sets (a) and (b) and positive for influenza B and enterovirus in set (c); (2) sample positive for human coronavirus 229/NL63 in set (a) and negative in set (b) and set (c); (3) sample negative in set (a), positive for human coronavirus OC43 in set (b), and positive for metapneumovirus in set (c); (4) sample negative in sets (a) and (b) and positive for metapneumovirus and enterovirus in set (c). PC: positive control; set (a) = 859 bp/PCR control, 534 bp/adenovirus, 375 bp/coronavirus 229/NL63, 264 bp/parainfluenza type 2, 189 bp/parainfluenza type 3, and 153 bp/parainfluenza type 1; set (b) = 850 bp/PCR control, 578 bp/coronavirus OC43, 394 bp/rhinovirus, 269 bp/respiratory syncytial virus A, 206 bp/influenza A, and 155 bp/respiratory syncytial virus B; set (c) = 579 bp/bocavirus, 456 bp/influenza B virus, 351 bp/metapneumovirus, 254 bp/parainfluenza virus type 4, 194 bp/enterovirus, and 153 bp/whole process control; NC: negative control.

Figure 2

Viral incidence by patient's age and viral type in 2010 and 2015.