Having a dumb and dumber kind of day? It might not be your fault. American researchers think they have found a virus that knocks a handful of points off the IQ test results of healthy people infected with the bug.

Dubbed the "stupidity virus" in various media reports but not the scientific study that found it, its technical name is ATCV-1, an algal virus. It was found by scientists at Johns Hopkins University in Maryland in throat cultures.

The virus usually infects green algae, but was found in human volunteers during a study on cognitive functioning. Test showed people with the virus performed about 10 percent slower on certain tests of mental skill.

Researchers from the University of Nebraska infected mice with the virus and found it had a similar effect on them. The rodents had difficulties finding their way through mazes, for instance.

The paper was published in an online scientific journal, Proceedings of the National Academy of Sciences (PNAS), in October.

Some are pushing back at the notion that the studies have any bearing on human intelligence at all. Virologist David Sanders of Purdue University told Forbes he would have to see the study replicated many times before he believed it.