Better diagnosis leads to better treatment – that’s well-known. Easier said than done, of course, since that’s not always possible when tests for diseases or infections take time to generate results, for example, or are inaccurate or insensitive. Take viruses: There is an abundance out there capable of causing disease, many of which can present similar symptoms or, perhaps worse, none at all. Detection can, therefore, be a bit of a nightmare, sometimes demanding a labor-intensive and costly suite of tests to get to the bottom of a case.
What if there was a universal, one-size-fits-all-test that could pick up any known virus in a sample, eliminating this time-consuming detective work? That might sound quite out of our clutches, but researchers at Washington University School of Medicine might just have achieved this long-awaited, eyebrow-raising feat.
“With this test, you don’t have to know what you’re looking for,” senior author Gregory Storch said in a statement. “It casts a broad net and can efficiently detect viruses that are present at very low levels. We think the test will be especially useful in situations where a diagnosis remains elusive after standard testing or in situations in which the cause of a disease outbreak is unknown.”
Describing their work in Genome Research, the results are pretty impressive. To make their “ViroCap,” the researchers began by creating a broad panel of sequences to be targeted by the test, which they generated using unique stretches of DNA or RNA found in viruses across 34 different human- and animal-infecting families. This resulted in millions of stretches of nucleic acid that can be used to capture matching strands in a sample, should they be present.
But the broad spectrum of this test is not its only remarkable quality: It’s so sensitive that it can even pick up slight variations in sequences, meaning that a virus’ subtype can also be identified – a feature not possible with many traditional tests. Although that wouldn’t necessarily change the way a patient is treated, it could aid disease surveillance.
To demonstrate its capabilities, the researchers took samples from a small group of patients at St. Louis Children’s Hospital and compared the results to those obtained from standard tests. While traditional sequencing managed to find viruses in the majority of the children, ViroCap also managed to pick up some common viruses that it had failed to detect. These included a flu virus and the virus responsible for chickenpox. In a second test run on a different group of children displaying fevers, the new test found an additional seven viruses to the 11 that the traditional testing managed to detect.
All of this sounds great on paper, but of course it is not yet ready to be used in the clinic. Further trials are required first to check its accuracy on larger groups of people, as so far only a limited number of patients have been screened. But when the time comes, the team plans to make it widely available, which would be welcome in the face of outbreaks like Ebola. Furthermore, the team ultimately hopes to tweak it so that it can detect genetic material from other microbes, like bacteria. If that’s possible, we could have a seriously useful machine on our hands that could change diagnostic medicine for the better.