THE ESSENTIAL
- Potentially dangerous new viruses can start spreading among people long before the global public health surveillance system can detect them with standard tests.
- Scientists hope that thanks to this advance, the spread of a new virus will be known and contained more quickly.
They are not very pleasant but they are eminently effective: nasal swabs, which we have become accustomed to with the Covid-19 epidemic, are very useful for discovering new potentially dangerous viruses, scientists have revealed.
Emerging disease: nasal swabs for early detection
They are commonly used on patients with suspected respiratory infections and are tested for specific signatures of 10 to 15 known viruses, say researchers at Yale University. But their role does not end there.
In their study published in the journal The Lancet Microbethey explain that they have discovered that by testing for the presence of a single molecule of the immune system on nasal swabs, it is possible to detect stealth viruses that are not identified by the usual tests.
So the swabs of people who tested negative for viruses”usual suspects“still showed signs of activating antiviral defenses – biomarkers, indicating the presence of an unknown virus.
Protein in nasal passages may be a sign of a new virus
The telltale sign was an elevated level of a single antiviral protein made by the cells lining the nasal passages, the authors say.
The researchers applied comprehensive genetic sequencing methods to ancient samples containing the protein, and in one they found an unexpected flu virus, called influenza C. Similarly, it is thanks to this new strategy of reanalysis of tests for the immune system biomarker they managed to screen four cases of Covid-19 which had not been diagnosed at the very beginning of the coronavirus epidemic, in March 2020.
“Finding a dangerous new virus is like looking for a needle in a haystack“said Ellen Foxman, associate professor of laboratory medicine and immunobiology and lead author of the study.”We found a way to drastically reduce the size of the haystack.“
