Multiple viral etiologies in patients with influenza-like illness and severe acute respiratory infection in Qatar, 2013–2016

Abstract

Presenter: Shazia Nadeem, Acting Head of Surveillance and Outbreak, Public Health Department, Ministry of Public Health, Doha, Qatar Background: Respiratory illnesses are a significant cause of morbidity and mortality. Qatar has a comprehensive surveillance system which includes influenza-like illness (ILI) and severe acute respiratory infection (SARI) and identification of the influenza and non-influenza viruses causing the infections. Purpose: The aim of this study was to determine the viruses causing acute respiratory illness in Qatar during 2013–2016. Methodology: Respiratory samples were collected from selected patients using WHO standard case definitions with ILI at the sentinel primary health care centre sites of the National Influenza Centre and patients with SARI admitted to sentinel hospitals. Nasopharyngeal and/or oropharyngeal swabs were collected from eligible patients (standardized case definitions) for the period 2013–2016. Samples were analysed by real-time polymerase chain reaction at the National Influenza Centre, which tests for 22 types and subtypes of virus. Findings: In the study period, 43 106 patients were included and tested, 29 626 (68.7%) of whom tested positive for infection. Out of these, 8 829 (29.8%) were influenza positive, 6 655 (75.4%) of whom were influenza A and 2 174 (24.6%) were influenza B. Sub-typing of influenza A showed 3 721 (55.9%) were influenza A(H1N1)pdm09. Other respiratory viruses isolated included rhinovirus 4 626 (15.6%), respiratory syncytial virus 3 259 (11.0%), coronaviruses 1 824 (6.2%), adenovirus 1 689 (5.7%), parainfluenza virus 1 645 (5.6%), human metapneumovirus 1 357 (4.6%) Mycoplasma pneumoniae 1 053 (3.6%), bocavirus 874 (3.0%) and parechovirus 178 (0.6%). Seasonal variation was observed for influenza with the peak season being from October to March with an unexpected surge of cases seen in October to December 2016. Conclusions: Influenza viruses A and B are responsible for the majority of the ILI and SARI cases reported in Qatar; however many other viruses also contribute to the burden of respiratory illness in the country. The findings indicate other viral etiologies besides influenza which may influence the clinical management and outcome of the patient. Keywords: Influenza; Influenza-like illness; Severe acute respiratory infection; Respiratory pathogens; Qatar