Is there a relationship between of viral load and co-infections of respiratory viruses with disease severity in patients with acute respiratory tract infection?

Abstract

Background: In this study, we aimed to investigate viral load of single or multiple respiratory viruses in patients with upper and lower respiratory tract infections and also whether there is a relationship between viral load and patient clinical characteristics. Methods: Between February 2014 and March 2015, nasopharyngeal swab specimens were collected from 930 [524 (56.3%) male, 406 (43.7%) female] patients with upper (521, %56.0) and lower (409, 44.0%) respiratory tract infections. The age range of patients is between 20 days to 87 years (median: 2 year). Nucleic acid was extracted (Ribospin vRD viral RNA/DNA Extraction Kit, GeneAll, Seegene, South Korea) and cDNA was synthesized (cDNA Synthesis Premix, Seegene, South Korea) according to the manufacturer’s protocol. Multiplex amplification of nucleic acid was performed using DPO primers [Influenza A&B virus (INF), RSV A&B, human adenovirus (ADV), human metapneumovirus (HMPV), human coronavirus (229E, NL63, OC43)(HCoV), parainfluenza virus type 1-4(PIV), human rhinovirus A/B/C(HRV), human enterovirus (HEV), and human bocavirus 1/2/3/4(HBoV)] and Anyplex II RV16 Detection kit (Seegene, South Korea). PCR product was detected by semi-quantitative real-time PCR on BioRad