VirScan, a new medical test, is capable of identifying all the viruses that have infected a person over his or her lifetime. This cutting-edge technique is capable of diagnosing a myriad of viral infections from less than a single drop of blood.
The human virome – the complete collection of viruses to infect humans – contains many microorganisms that do not cause diseases, and some do not even cause symptoms. However, the presence of some viruses in the human body can radically alter the immune system.
Current diagnostic methods search for antibodies left behind by viruses, but they are limited by the number of the proteins that can be tested sought in a single examination.
To use the new technology for screening, harmless viruses were engineered with components of viruses capable of infecting humans. These protein fragments act as triggers for the natural defense mechanisms of the human body. VirScan mixes the drop of blood with these modified viruses, and in observing which of the decoys is attacked by antibodies, it is possible to determine the past record of viral infections.
The diagnostic device was tested on 569 subjects from four continents around the globe. VirScan identified an average of 10 viral species in average patients.
"George Xu and colleagues used a large dataset of peptides from 206 viral species, representing more than 1,000 different viral strains, to create a synthetic representation of all human viral peptides," reported the American Association for the Advancement of Science (AAAS).
VirScan developers believe their invention will help medical researchers better understand the interactions between the human virome and immune system. Doctors could soon be able to perform a single test to screen patients for a wide range of viral infections, both present and past. VirScan could also detect HIV and hepatitis C infections long before current tests would be able to find evidence of the virus.
"Normally, when a doctor wants to know if someone's been infected with a virus, they have to guess what the virus is, and then look specifically for that virus. This could lead to a diagnostic where people go annually to their doctor and get their viral history recorded. It could certainly discover viral infections that are serious and that a patient didn't know they had," said Stephen Elledge from Brigham and Women's Hospital in Boston.
The test, which costs just $25, is based on rapid gene sequencing and synthetic biology technologies capable of searching for thousands of antibodies at once.
Of the people examined in the study, those with the greatest number of past infections had been exposed to up to 84 varieties of viruses.
Future development of the technique could allow it to detect records of bacterial infections, as well as past exposures to protozoa and fungus.
The development of the VirScan system was detailed in the journal Science.
Photo: Dominic Alves | Flickr