(Aug. 5, 2002)
The microorganism that caused a sensation when it was discovered in the same waters as pockmarked fish may cause human illness, but predicting and measuring its effects in humans and fish alike will be difficult, according to a recent article by researchers at the Brody School of Medicine at East Carolina University.
Toxins of Pfiesteria piscicida and Pfiesteria-complex organisms have not yet been identified, isolated and purified in sufficient quantities to develop methods of diagnosing ailments they might cause, according to the review study by Dr. William Burke, a professor of medicine and head of the dermatology division at the Brody School of Medicine at ECU, and Dr. David N. Collier, who was a medical student at the time of the study and is now a pediatric resident at ECU. The review appeared in the July issue of the Southern Medical Journal.
Collier and Burke reviewed studies and information about Pfiesteria and PCOs in an effort to evaluate the threat these organisms pose to human health.
"The study was done to educate regional physicians about Pfiesteria and to clear up misconceptions created by the lay press about the organism and its possible effects on human health," Burke said.
A single-celled organism with a complex life cycle, Pfiesteria was first shown to kill fish in a laboratory setting in 1988 and has been associated with fish kills mainly in estuarine waters of North Carolina. PCOs have been recovered in waters from Delaware Bay to the Gulf of Mexico and have been implicated in fish kills in Maryland, Virginia and possibly Florida. What role exactly Pfiesteria or PCOs played in these fish kills isn't known.
Laboratory researchers working with water containing high concentrations of organisms reported respiratory, skin and cognitive problems, among other ailments. But studies of crabbers and examination of others possibly exposed to PCOs showed no unusual symptoms or illnesses that couldn't be attributed to other causes.
The article advises more research into whether Pfiesteria and PCOs pose a health risk to humans.
"I think that ongoing and future research will show that the organism's effect on human health in estuarine systems may have been grossly overstated," Burke said. "Common sense should always prevail, however, and people should avoid waters where there are dead or dying fish. In addition, cuts and sores of human skin should always be protected from water or when handling fish."