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

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. 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. 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. 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. 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.