Nasal swabs can help detect emerging viruses

New emerging and potentially dangerous viruses they can spread through the population to reach pandemic levels, as has happened with the SARS-CoV-2 coronavirus long before the global public health surveillance system can detect them and put in place measures to protect citizens, especially groups more vulnerable. It is a lesson we have learned from the pandemic by COVID-1.

A team of researchers from Yale University has made a finding, however, that could help to identify this type of pathogen early; Specifically, they have discovered that tests to detect the presence of a single immune system molecule in nasal swabs can help detect unidentified stealth viruses in standard tests, as published in The Lancet Microbe.

“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 significantly reduce the size of the haystack.”

Public health experts look for red flags of emerging diseases in certain sources. They study emerging viruses in animals that can transmit the infection to humans, but it is difficult to determine which of the hundreds, if not thousands, of new viral variants represent a real danger. They also investigate the Unexplained outbreaks of respiratory illnesseswhich was how SARS-Cov-2 was discovered in China at the end of 2019, but sometimes it can be too late.

An antiviral protein that alerts unknown viruses

Foxman and his team reviewed a finding from their lab in 2017 because they thought it might provide a new way to monitor for unexpected pathogens. Nasal swabs are usually taken from patients with suspected respiratory infections and analyzed for specific signatures of 10 to 15 known viruses. Most tests come back negative, but in 2017 these scientists observed that, in some cases, swabs from those who tested negative for “usually suspected” viruses continued to show signs that antiviral defenses were activated, indicating the presence of a virus. The warning sign was a high level of a single antiviral protein Produced by cells lining the nasal passages.

Based on this finding, the researchers applied comprehensive genetic sequencing methods to old samples containing the protein, finding an unexpected influenza virus called influenza C in one of the samples. During the first two weeks of March 2020, they retested old samples. to search for unidentified cases of COVID-19.

Hundreds of nasal swab samples collected from patients at New York’s Yale-New Haven Hospital during that time tested negative for standard characteristic viruses. When tested for the immune system biomarker, most of those samples showed no trace of antiviral defense system activity, but a few did, and among them they found four cases of COVID-19 that had not been diagnosed at the time.

The study results reveal that testing for an antiviral protein produced by the body, even if tests for known respiratory viruses are negative, can help identify which nasal swabs are most likely to contain unexpected viruses.

The detection of this biomarker it would allow researchers to narrow down the search for unexpected pathogens, making it possible to monitor for the emergence of unexpected viruses using swabs collected during routine patient care. Samples containing the biomarker can be tested using more sophisticated genetic testing methods to identify unexpected or emerging pathogens circulating in the patient population and promote a response from the scientific and medical community.


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