Thousands of viruses are known to infect humans and other animals, which makes diagnosis an arduous guessing game for doctors. But now researchers at Washington University in St. Louis have developed an all-in-one test that can detect and identify nearly any viral infection known to exist.

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The method is called ViroCap, and it works so well that you don't even need a doctor's examination to get the correct diagnosis.

“With this test, you don’t have to know what you’re looking for,” said the study’s senior author, Dr. Gregory Storch, M.D. “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.”

ViroCap will also help to efficiently sort through viruses that cause similar symptoms, reducing the perils of incorrect diagnoses. In fact, when an experiment was performed to test ViroCap against standard tests, the number of viruses detected among patients in the study jumped to 32 from 21, a 52 percent increase. In other words, ViroCap was able to detect infections that would have gone unnoticed in standard tests.

In one example from the study, standard testing identified a virus as influenza A, which causes seasonal flu, but the new test indicated that the virus was actually a particularly harsh subtype called H3N2. This kind of information can be extremely important when it comes to assigning treatment; it could even be the difference between life and death.

So how does the test work? Researchers first analyzed every known group of virus that infects humans and animals, and identified unique stretches of DNA or RNA found in each. These stretches of material are then used as "probes" to pluck out viruses from patient samples that are a genetic match. High-throughput genetic sequencing then narrows it down to a specific virus.

The test will require further study before it can be employed by doctors everywhere, so it may take a few years before it is available. The good news, though, is that this method could potentially be developed to identify infections that aren't even viral, making it a truly universal tool.

“It also may be possible to modify the test so that it could be used to detect pathogens other than viruses, including bacteria, fungi and other microbes, as well as genes that would indicate the pathogen is resistant to treatment with antibiotics or other drugs,” explained co-author Kristine Wylie, Ph.D.