On Thursday, researchers from Brigham and Women's Hospital and Harvard Medical School reported that a new blood test can reveal a person’s entire virus history.

According to researchers, the $25 test known as VirScan can detect past exposure to more than 1,000 strains of viruses from 206 species. It works by detecting antibodies, highly specific proteins the immune system has made in response to viruses.

The test was tried on 569 people in the United States, South Africa, Thailand, and Peru. The findings revealed that many of them had been exposed to about 10 species of virus.

Most of these were the ones that cause cold, flu, and gastrointestinal illness. But a few had evidence of exposure to 25 species, something the researchers had yet to explain.

Stephen J. Elledge, the senior author of the report and a professor of genetics at Harvard Medical School and Brigham and Women’s Hospital, said, “There were some differences from continent to continent. In general, people outside the US had higher rates of virus exposure. The reason is not known, but the researchers said it might be due to differences in population density, cultural practices, sanitation, or genetic susceptibility”.

According to the researchers, the test could become an important research tool for tracking patterns of disease in various populations. Additionally, it could be used to try to find out whether viruses or the immune respond to them or contribute to chronic diseases and cancer.