ST. LOUIS, Sept. 29 (UPI) -- Researchers have developed a new test that can detect nearly any virus known to infect humans and animals, offering the potential to help doctors diagnose infections even without a clue of what they are looking for.
The test, called ViroCap, is likely years from being used regularly with patients because its accuracy needs to be verified in extensive clinical trials. The technology is being made publicly available, however, to scientists and doctors as it continues to be developed.
"With this test, you don't have to know what you're looking for," said Dr. Gregory Storch, a professor of pediatrics at Washington University in St. Louis, in a press release. "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."
The researchers created a panel with sequences and tests DNA and RNA from viruses in 34 organism families, and was found to be just as sensitive as polymerase chain reaction, or PCR, assays but can test for all the viruses at once -- which traditional tests can't do. It can also test for variations on more common viruses, offering the potential to catch infections that doctors may never even consider.
In two sets of samples, from blood, stool and nasal secretions, researchers compared the results of standard PCR tests against the ViroCap. The PCR caught viruses in 10 of 14 patients, however the ViroCap detected viruses in the other 4 patients. The viruses missed were relatively common -- influenza B, a cause of seasonal flu; parechovirus, a mild gastrointestinal and respiratory virus; herpes virus 1, responsible for cold sores in the mouth; and varicella-zoster virus, which causes chickenpox.
In a second group of children with unexplained fevers, the standard test detected 11 viruses in 8 children. The new test, however, found 7 more, including a generally harmless respiratory virus called human adenovirus B type 3A that can, occasionally, cause severe infections.
Overall, the researchers reported that ViroCap had a 52 percent improvement over PCR tests for viruses, jumping from 21 to 32 being detected.
"The test is so sensitive that it also detects variant strains of viruses that are closely related genetically," said Todd Wylie, a pediatrics professor at Washington University. "Slight genetic variations among viruses often can't be distinguished by currently available tests and complicate physicians' ability to detect all variants with one test."
Researchers said they plan to continue to refine the refine the test and validate its accuracy well beyond the small trials they conducted. The test also will be publicly released so that other researchers and doctors can work with, use and improve it.
The study is published in Genome Research.
