Typically, GI symptoms are more prominent in children with influenza than adults but during the H1N1 epidemic in 2009 (which has subsequently become endemic), up to 26% of hospitalized adults with H1N1 infection had abdominal pain or vomiting and up to 25% had diarrhea (1). In fact, H1N1 virus has been isolated from stool of adult hospitalized patients (2).
Interestingly, the mechanism involved in influenza-mediated intestinal injury may have less to do with direct invasion of the intestinal mucosa by the virus and more to do with immune mediated changes related to alterations in the intestinal microbiota induced by influenza virus infection itself (3)! Who would have thought?
- Writing Committee of the WHO Consultation on Clinical Aspects of Pandemic (H1N1) 2009 influenza. Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med 2010;362:1708-19.
- Yoo SJ, Moon SJ, Kuak E-Y, et al. Frequent detection of pandemic (H1N1) 2009 virus in stools of hospitalized patients. J Clin Microbiol 2010; 48:2314-2315.
- Wang J, Li F, Wei H, et al. Respiratory influenza virus infection induces intestinal immune injury via microbiota mediated Th17 cell-dependent inflammation. J Exp Med 2014;211:2397-2410.