Animal studies exploring the effects of a toxin from the microscopic marine organism Pfiesteria piscicida have found that exposure to this substance can cause learning deficits. This toxic dinoflagellate, which has killed millions of fish in Maryland and North Carolina, has been implicated in neurological problems in people unintentionally exposed to the substance in the laboratory or in the field.
Several scientists exposed to the organism in a research laboratory experienced a range of symptoms, including dramatic mental impairment, memory loss, disorientation, emotionality, immune problems, and skin sores. These disturbing symptoms prompted the research team, which included investigators from Duke University Medical Center, Durham, NC, and North Carolina State University, Raleigh, the Environmental Protection Agency, and the National Institute of Environmental Sciences (NIEHS), to undertake the animal studies.
Stephenson J. Pfiesteria and Learning Problems. JAMA. 1998;279(3):188. doi:10.1001/jama.279.3.188-JHA71007-4-1