Abstract
Here, we investigated the molecular and biological characteristics of intestinal influenza viruses and their potential role in virus transmission. Fecal samples were first screened for the presence of influenza viral RNA using RT-qPCR. Positive fecal samples were subjected to cell culture. Isolated viruses were then sequenced using MiSeq platform. Replication kinetics and receptor binding affinity were also evaluated. Influenza RNA was detected in stool samples of 41% (36/87) of influenza A positive patients. Among the 36 stool samples subjected to viral isolation, 5 showed virus growth. Sequence analysis of isolated viruses revealed two distinct mutation patterns in fecal viruses. Set I viruses was able to replicate to higher titers in cell culture despite the limited number of mutations (6 mutations) compared to set II viruses (>10 mutations). Functional analysis of both sets revealed the ability to replicate efficiently in differentiated human bronchial cells. Receptor binding testing has also demonstrated their ability to bind α 2,3 and α 2,6 sialic acid receptors. The ability of fecal influenza viruses to replicate in intestinal cells and human 3D bronchial cells might suggest their possible contribution in virus transmission.
Highlights
Human influenza viruses primarily infect respiratory cells resulting in a wide range of respiratory illnesses (Pang et al, 2013; World Health Organisation, 2020)
Madin-Darby canine kidney cells (MDCK) cells were seeded on 96-well plates and infected the following day for 2 h with 10 log di lutions of virus in infection medium (IM)
Influenza viruses infect cells through binding to sialic acid receptors which are commonly expressed in many human cell tissues
Summary
Human influenza viruses primarily infect respiratory cells resulting in a wide range of respiratory illnesses (Pang et al, 2013; World Health Organisation, 2020). Typical influenza like illness (ILI) includes fever (>39 ◦C), muscle pain, sore throat and cough, severe symp toms are commonly observed among high risk groups (World Health Organisation, 2020). The avian influenza virus, H5N1, is the only influenza A virus known to replicate in human intestine and to cause severe gastrointestinal symptoms (de Jong et al, 2005; Uiprasertkul et al, 2005). Seasonal influenza viruses have been shown to cause gastrointestinal symptoms for more than 30 years (Price et al, 1976; Peltola et al, 2003; Wootton et al, 2006). During the two epidemics in 1973 and 1974, influenza B virus was detected in hospitalized children admitted due to severe abdominal pain (Kerr et al, 1975). It is possible that GI symptoms could develop due to the side effects of drug treatment, a co-infection with other enteric pathogens, or the dissemination of virus to intestinal tract
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
