The Prevalence of Respiratory Viruses Among Patients with Influenza-Like Illness in Zahedan, Southeastern Iran

Background: Acute viral respiratory diseases are among the most prevalent diseases in humans. Viral respiratory infections are the main reasons for hospitalization and death in developing countries. Objectives: The aim of this study is to determine the prevalence and clinical symptoms of the respiratory viruses including influenza viruses A and B, respiratory syncytial virus type A and B (RSV-A and RSV-B), human parainfluenza virus type 1 to 4 (HPIV-1-4) among patients with Influenza-like illness (ILI) in Zahedan City, Southeastern Iran from October 2015 to March 2016. Methods: Clinical and epidemiological data from patients who presented to outpatient clinics with ILI from October 2015 to March 2016 in Zahedan were collected. A total of 240 throat swabs were tested for Influenza virus by RT-PCR, and then those with negative results were tested for RSV-A, RSV-B, and HPIV type 1 - 4 using Multiplex-PCR. Results: Among 240 patients, 115 (47.9%) were male and 125 (52.1%) were female. Influenza A virus was detected in 196 (81.7%) patients, out of them 157 (65.4%) had H1N1 subtype and the remaining patients had H3N2 subtype. Influenza B virus was observed in 9 (3.8%) patients. Respiratory syncytial virus type A and B, and human parainfluenza virus type 1 to 4 were not detected in this study. The highest rate of influenza A infection was in the age range of 16 - 45 years old and for influenza B was in the age group of more than 46 years. The most common clinical manifestations in both influenzas A and B were fever, cough, and myalgia. Over half of the patients with influenza B had dyspnea compared to 30% of ILI patients with influenza A virus infection. Conclusions: The results of the study revealed the highest rate of Influenza A infection with H1N1 subtype among patients presented to the outpatient clinics with the clinical manifestations of influenza-like illness. This study suggests continuing surveillance, infection control, and annual vaccination for Influenza.