The algae virus, never before observed in healthy people, was found to affect cognitive functions including visual processing and spatial awareness, The Independent reports.  
 

Scientists at Johns Hopkins Medical School and the University of Nebraska made the discovery while undertaking an unrelated study into throat microbes. They found DNA in the throats of healthy individuals that matched the DNA of a virus known to infect green algae.
 

“This is a striking example showing that the ‘innocuous’ microorganisms we carry can affect behavior and cognition,” said Robert Yolken, M.D., a virologist who led the study. “Many physiological differences between person A and person B are encoded in the set of genes each inherits from parents, yet some of these differences are fuelled by the various microorganisms we harbor and the way they interact with our genes.”
 

Of the 90 participants in the study, 40 tested positive for the algae virus. Those who tested positive performed worse on tests designed to measure intelligence and attention.
 

The study’s findings were published in the Proceedings of the National Academy of Sciences.