BACKGROUND: The clinical features of avian-origin influenza virus A (H7N9) virus infection have been extensively characterized, but viral RNA detection in extra-pulmonary samples has seldom been studied.
OBJECTIVES: To study shedding of viral RNA in extra pulmonary samples in patients with avian influenza H7N9 infections.
STUDY DESIGN: A retrospective study of throat swabs, urine, fecal samples and sera collected sequentially from 18 hospitalized patients with H7N9 infections in Shanghai, China, between April and July in 2013 was conducted.
RESULTS: Viral RNA could be detected in urine samples from 17 patients, in fecal samples from 15 and in sera from 14 with a real-time reverse transcription polymerase chain reaction. The median duration of shedding of viral RNA was 19.7 days in throat swabs, 22 days in feces, 21.1 days in urines and 16.2 days in sera, indicating prolonged shedding of viral RNA in feces and urine compared with that in throat swabs. Prolonged duration of viral RNA detection in throat swabs and urine samples was observed in more severe patients. Moreover, in previously reported oseltamivir resistant patients, the NA gene with a 292K mutation could also be detected in their extra-pulmonary as well as in their respiratory samples.
CONCLUSION: Our data indicated a high frequency of viral RNA detection in feces, urine and sera in H7N9-infected patients and pointed out the potential risk of transmission.