Researchers from the Washington University in St. Louis have developed a new test capable of detecting nearly all viruses known to infect humans and animals. The test could potentially help doctors diagnose infection regardless if they do not have a clue what they are looking for.
The accuracy of the test called Virocap still needs to be tested in clinical trials so it may still take years before it can be used with patients but the technology is already made available to health service providers and researchers as it is being developed.
Thousands of viruses cause illnesses in both people and animals and this makes diagnosis difficult sometimes requiring a range of different tests. Currently available tests are not sensitive enough for detecting low levels of viral bugs or can only detect viruses that are suspected of being the cause of a patient's illness.
What make Virocap different is that physicians do not have to know what they are searching for, said pediatrics professor Gregory Storch. He added that the test can be especially helpful in situations when a pathogen behind a disease outbreak is not known or when diagnosis continues to be elusive after standard tests.
For their research, which they reported in a study published in Genome Research on Sept. 22, 2015, Storch and colleagues evaluated the Virocap test in stool, blood and nasal secretions of 14 patients.
Standard testing detected viruses in only 10 of the patients and failed to detect common viruses such as parechovirus, influenza B and herpes virus. The new test, though found the virus in the four patients that earlier testing with genome sequencing had missed.
"The test is so sensitive that it also detects variant strains of viruses that are closely related genetically," said researcher Todd Wylie, a pediatrics instructor. "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."
In another set of eight children suffering from unexplained fever, standard testing detected 11 viruses but Virocap found another seven, which includes a respiratory virus that is often harmless but can cause severe infections in some individuals.
The number of viruses that were detected in these two sets of patients increased from 21 to 32, or a jump of 52 percent.
"We have created a targeted sequence capture panel, ViroCap, designed to enrich nucleic acid from DNA and RNA viruses from 34 families that infect vertebrate hosts," the researchers wrote. "ViroCap substantially enhances Metagenomic shotgun sequencing (MSS) for a comprehensive set of viruses and has utility for research and clinical applications."
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