Risk factors for seasonal influenza virus detection in stools of patients consulting in general practice for acute respiratory infections in France, 2014-2016

Abstract

Background: Previous studies reported detection of influenza RNA in stools of patients with seasonal influenza infection. While this detection may have a clinical significance, other factors may influence the stool positivity for influenza viruses. Objectives: The objective of this study was to investigate demographical, clinical, and microbiological factors which could favor the presence of influenza viral RNA in the stools of patients with laboratory-confirmed influenza infection. Methods: Acute respiratory infection (ARI) patients were enrolled by general practitioners (GP) during two winter seasons (2014-2016). Nasopharyngeal swabs, stool specimens, and clinical data were collected. Samples were tested for 12 respiratory pathogen groups (nasopharyngeal and stool specimens) and for 12 enteric pathogens (stool specimens). Results: Among the 331 patients with ARI enrolled by GP, 114 (34.4%) presented influenza infection. Influenza RNA was detected in stool samples of 21% (24/114) of the 114 stool specimens analyzed. Hospitalization (adjusted odds ratio (aOR) = 7.8 (95% confidence interval (CI)) [1.7-33.7], P =.02), age between 45 and 64 years (aOR = 4.8 [1.7-14.5], P =.01), consumption of raw shellfish and/or mollusks (aOR = 16.7 [3.6-90.9], P =.00), and use of antibiotics (aOR = 6.4 [2.1-19.8], P =.006) or antiviral treatment (aOR = 7.4 [1.9-29], P =.01) were significantly associated with an increased odds of the detection of influenza RNA in stools. Among the 24 stool samples subjected to viral isolation, no one showed virus growth. Conclusions: These findings will be useful to studies investigating the dissemination route of influenza viruses to gastrointestinal tract.