EU.- Researchers led by Yale University, USA, have developed a technique that, using a nasal swab test, can help detect stealthy (emerging) viruses not detected by standard tests. The achievement is based on the detection of a single antiviral molecule of the immune system called CXCL10, they recently reported.
The team of scientists was looking for a new way to monitor for unexpected pathogenic viruses. Nasal swabs are commonly taken from patients suspected of having respiratory infections and tested for specific fingerprints of 10 to 15 known viruses. Although most tests come back negative for the “usual suspect” viruses, some patients still show signs that antiviral defenses were activated, indicating the presence of a virus.
a key sign
The telltale sign was a high level of the antiviral protein CXCL10 produced by the cells lining the nasal passages. Based on that finding, the researchers applied comprehensive genetic sequencing methods to ancient samples containing the key protein, and in one sample, found an unexpected influenza virus called influenza C.
Applying this approach in retrospect, the team found four cases of covid-19 that could not be diagnosed at the start of the pandemic in 2020, since diagnostic systems for this virus had not yet been developed. The findings reveal that testing for this body-produced antiviral protein, even if tests for known respiratory viruses are negative, can help identify which nasal swabs are most likely to contain unexpected viruses.
Find the needle by reducing the size of the haystack
Specifically, detection of the nasopharyngeal biomarker would allow researchers to narrow down the search for unexpected pathogens, making surveillance for unexpected viruses feasible using swabs collected during routine patient care. Samples possessing CXCL10 can be tested using more sophisticated genetic testing methods to identify unexpected or emerging pathogens circulating in the patient population and prompt a response from the healthcare community.
“Finding a dangerous new virus is like looking for a needle in a haystack,” said Ellen Foxman, professor and lead author of the study. “We found a way to significantly reduce the size of the haystack.” The results of this study were recently published in The Lancet Microbe.
