Screening for influenza viruses in 7804 patients with influenza-like symptoms

Objectives: To screen a large number of patients with influenza-like symptoms by using the gold-immunochromatographic assay kit. Methods: All patients with influenza-like symptoms visiting the outpatient department of the General Hospital of Beijing Military Region, Beijing, China between May 2009 and January 2010 were enrolled in the study. Nasopharyngeal swabs were collected immediately after the patient visited, then a gold-immunochromatographic assay was performed for screening of influenza A and B viruses according to the kit protocol. Results: Among the 7804 patients enrolled in this study, 202 patients were influenza virus-positive; the positive cases accounted for 2.6% of all cases detected. Among the 202 influenza virus-positive patients, 171 patients were influenza virus A-positive, 24 were influenza virus B-positive, and 7 were co-infected with influenza virus A and B. More than 57% of the virus-positive patients were younger than 30 years old. Symptoms such as fever, sore throat, nasal congestion, sneezing, runny nose, and joint pain were more frequently observed in influenza virus A-positive patients than in influenza virus B-positive and influenza virus-negative patients. Conclusion: The gold immunochromatographic assay kit is very useful for screening a large number of patients with influenza-like symptoms. A higher number of influenza virus A-positive patients have sore throat, nasal congestion, sneezing, runny nose, and joint pain than influenza virus B-positive and influenza virus-negative patients.