A single test has been developed that can scan the antibodies in your bloodstream and detect signs of every virus you've ever been exposed to, researchers have announced.
The DNA-based blood test that yields a person's viral history could aid in early detection of many conditions and might eventually help explain what triggers certain autoimmune diseases and cancers, they say.
In contrast to existing tests, most of which are targeting one virus at a time, the new technique — dubbed VirScan — can simultaneously analyze a single drop of blood for more than 1,000 viral strains, researchers at Harvard University report in the journal Science.
To develop the test to detect both current and past infections a person has been exposed to, the researchers assembled a library of thousands of protein fragments found in some 206 viruses, which covers just about the entire human "virome," the collection of strains known to be capable of infecting people.
When they are added to a drop of blood, antibodies for specific proteins will attach themselves, identifying which viruses a person has been in contact with.
It works for both current and past exposure, the researchers explain, because the immune system will continue to produce specific antibodies for decades after the original infection subsides.
While seen as an advance over existing diagnostic tests, the $25 technique will likely be of more use as a research tool for now, its developers say.
VirScan "allows scientists to ask questions that just couldn't be asked before," says biologist Stephen Elledge at the Harvard Medical School. "You can compare groups of people — young and old or those with a disease and those without — and see whether there's a difference in their viral histories."
In a test on more than 500 people in the United States, Peru, Thailand and South Africa, VirScan showed most people have been exposed to around 10 different species of virus, mostly common varieties like those that cause the common cold or the flu, gastrointestinal illnesses or other common conditions.
Some, however, showed evidence of exposure to as many as 25 strains, the researchers say.
The possible uses of the test are just beginning to become apparent, Elledge says.
"That's what happens when you invent technology — you can't imagine what people will do with it," he says.
Other researchers not involved in the study agreed the test could have vast potential.
"This will be a treasure trove for communicable disease epidemiology," says Dr. William Schaffner, an infectious disease expert at Vanderbilt University. "It will be like the introduction of the electron microscope."
