ATCV-1 (Acanthocystis turfacea Chlorella virus 1) is a virus that impairs cognitive capabilities (or in other words, it makes its victims dumber), and this has been confirmed by laboratory tests performed on mice. I have collected articles from the internet about this virus here for your convenience.
This virus is being scientifically investigated by Dr. Robert Yolken, M.D., a virologist and pediatric infectious disease specialist at the Johns Hopkins Children's Centre and director of the Stanley Neurovirology Laboratory at Johns Hopkins. James Van Etten of the University of Nebraska is an expert on algal viruses and was a senior author involved in documenting ATCV-1. Other researchers from the University of Nebraska include David Dunigan, James Gurnon, Fangrui Ma, and Irina Agarkova.