A new study at Johns Hopkins says a virus that infects human brains has been discovered and the virus lowers human intelligence.

The algae virus impacts cognitive functions including visual process and special awareness according to a report in the Independent UK newspaper.

The study by scientists at Johns Hopkins and the University of Nebraska started completely by accident during an investigation into throat microbes.  The DNA of virus that infects green algae was found in the throats of healthy individuals.

“This is a striking example showing that the ‘innocuous’ microorganisms we carry can affect behavior and cognition,” Dr. Robert Yolken told the Independent.

In the study, 40 people in 90 tested positive for the algae virus.  All 40 of the positive subjects scored lower on tests to measure speed and accuracy of visual processing.  They also had lower attention spans.

The study was published in the Proceedings of the National Academy of Sciences.