Persisting learning deficits in rats after exposure to Pfiesteria piscicida.

Journal Article (Journal Article)

Pfiesteria piscicida and other toxic Pfiesteria-like dinoflagellates have been implicated as a cause of fish kills in North Carolina estuaries and elsewhere. Accidental laboratory exposure of humans to P. piscicida has been reported to cause a complex syndrome including cognitive impairment. The current project was conducted to experimentally assess the possibility of cognitive effects of P. piscicida exposure in rats. Samples of water from aquaria in which P. piscicida zoospores were killing fish were frozen, a procedure that has been found to induce encystment. Thawed samples were injected into albino Sprague-Dawley rats. A significant learning impairment was documented in rats administered samples of P. piscicida that were recently frozen. Prolonged storage of Pfiesteria samples diminished the effect. No effect was seen in the recall of a previously learned task, but when the rats were called upon to learn a new task, the Pfiesteria-treated animals showed a significant learning deficit. This effect persisted up to at least 10 weeks after a single injection of Pfiesteria. The Pfiesteria-induced learning deficit did not seem to be associated with any obvious debilitation or health impairment of the exposed rats. Deficits in habituation of arousal and rearing behavior were detected using a functional observational battery. No Pfiesteria-induced effects on blood count and white cell differential or in a standard pathological screening of brain, liver, lung, kidney, and spleen tissue were seen at 2 months after exposure. These studies document a persistent learning impairment in rats after exposure to the dinoflagellate P.piscicida in otherwise physically well-appearing rats. This effect may partially model the symptoms of cognitive impairments that humans have shown after Pfiesteria exposure.

Full Text

Duke Authors

Cited Authors

  • Levin, ED; Schmechel, DE; Burkholder, JB; Deamer-Melia, NJ; Moser, VC; Harry, GJ

Published Date

  • December 1997

Published In

Volume / Issue

  • 105 / 12

Start / End Page

  • 1320 - 1325

PubMed ID

  • 9405328

Pubmed Central ID

  • PMC1470419

International Standard Serial Number (ISSN)

  • 0091-6765

Digital Object Identifier (DOI)

  • 10.1289/ehp.971051320


  • eng

Conference Location

  • United States