Viruses are microscopic packets of DNA that cannot reproduce on their own, so they infect living cells of species like ours. Once inside, they harness the cell's abilities to manufacture more virus. But what if that cell is already infected by a virus? Or two viruses invade at the same time? A study from the University of Glasgow set up human lung cells in a lab and gave it two different respiratory viruses to find out the results of this "co-infection."
Research shows that up to 30% of infections may harbour more than one virus. What this means is that, at some point two different viruses are infecting the cells that line your nose or lungs.
We know that co-infection can be important if we look at a process called “antigenic shift” in influenza viruses, which is basically caused by virus “sex”. This sometimes occurs when two different influenza strains meet up inside the same cell and exchange genes, allowing a new variant to emerge.
Co-infection can create a predicament for viruses when you consider that they need to compete for the same resource: you. Some viruses appear to block other viruses, while some viruses seem to like each other. What is driving these positive and negative interactions during co-infections is unknown, but animal studies suggest that it could be critical in determining how sick you get.
The experiment yielded some resulting virus particles that had DNA from both infectious viruses, what they called a "chimeric" virus. Read about the research and its implications at Real Clear Science.
(Image credit: Yale Rosen)
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