Study: algae in throat could lead to subtle changes in cognitive function

Nov. 12, 2014

Scientists from Johns Hopkins and the University of Nebraska have discovered an algae virus in the throats of healthy people that may subtly alter a range of cognitive functions, including visual processing and spatial orientation, in those who harbor it. The discovery casts in a new light a class of viruses that has thus far been deemed non-infectious to humans, underscoring the ability of certain microorganisms to trigger delicate physiologic changes without causing full-blown disease, the researchers say. A report on the team's findings was published online recently in Proceedings of the National Academy of Science.

Lead investigator Robert Yolken, MD, and colleagues stumbled upon the algae virus unexpectedly while analyzing the microbial population of the throats of healthy humans for a non-related study. Investigators obtained throat swabs and performed DNA analysis designed to detect the genetic footprints of viruses and bacteria. To their surprise, the researchers say, they discovered DNA matching that of Acanthocystis turfacea Chlorella virus 1, or ATCV-1, known to infect green algae.

Forty of 92 participants in the study tested positive for the algae virus, and the group that harbored the virus performed worse overall on a set of tasks to measure the speed and accuracy of visual processing. While their performance was not drastically poorer, it was measurably lower, the researchers say.

To further elucidate the effects of the virus, the investigators infected a group of mice and analyzed their performance on a set of tests designed to measure the rodent equivalent of human cognitive function. Animals infected with the virus exhibited deficits similar to those observed in humans. Infected animals had worse recognition memory and spatial orientation than uninfected mice. For example, they had a harder time finding their way around a maze, failing to recognize a new entry that was previously inaccessible. Read the study abstract.

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