Researchers say they have created a test to detect any virus that infects people and animals, eliminating the need for doctors to perform multiple tests before confirming a diagnosis. Researchers at the Washington University School of Medicine in St. Louis published their findings on the ViroCap in the September issue of the journal Genome Research.
“With this test you don’t have to know what you’re looking for,” Gregory Storch, senior study author and Ruth L. Siteman professor of pediatrics, said in a news 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.”
According to the news release, the test sequences and detects viruses in patient samples as accurately as the system used in clinical laboratories called polymerase chain reaction (PCR). Storch and his fellow authors believe the test could be used to detect deadly viruses like Ebola, Marburg, SARS and other routine viruses like rotavirus and norovirus.
To evaluate the ViroCap, researchers used two sets of biological examples from patients at St. Louis Children’s Hospital. In the first evaluation, standard testing that relied on genome sequencing had detected viruses in 10 of 14 patients, while the new tests found viruses in the four children that earlier testing had missed. Standard testing failed to detect influenza B, parechovirus, herpes virus 1 and the virus that causes chickenpox.
In the second evaluation, which included children experiencing unexplained fevers, standard testing detected 11 viruses in the eight children evaluated, while the new test found an additional seven, including a respiratory virus. Overall, researchers recorded that the number of viruses detected increased by 52 percent with the new test.
“The test is so sensitive that it also detects variant strains of viruses that are closely related genetically,” study author Todd Wylie, instructor of pediatrics at Washington University, said in the news release. “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.”
To develop the ViroCap, researchers targeted unique stretches of DNA or RNA from every known group of viruses that infects humans and animals, totaling 2 million unique stretches of material from viruses in the test. According to the release, the stretches of material are used as probes to pluck out viruses in patient samples that are a genetic match, and it is then analyzed using high-throughput genetic sequencing. Researchers said that as viruses are discovered, it will be easy to add their genetic material to the test.
“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,” Kristine Wylie, co-author and assistant professor of pediatrics, said in the news release.