Disclaimer: These postings were sent to us from a variety of media sources over the Internet. The content has not been reviewed for scientific accuracy or edited in any manner.
Discovery shifts focus off Pfiesteria / This parasite may be working with 'cell from hell,' other organisms in fish kills By Rex Springston
Richmond Times Dispatch
Tuesday, November 9, 1999Scientists discovered an unusual microscopic parasite killing fish in the James River last month, and they say the creature may be responsible for some of the fish attacks attributed to the toxic microbe Pfiesteria.
Pfiesteria, the so-called "cell from hell," has been blamed for killing thousands of fish on the Eastern Shore of Virginia and Maryland and more than a billion in North Carolina.
"We have some very strong evidence now that probably a lot of the earlier events that were attributed to Pfiesteria probably weren't related to Pfiesteria at all," said Dr. Greg C. Garman, a Virginia Commonwealth University fish biologist.
Garman and other researchers found the parasite, called Kudoa, afflicting hundreds of fish that were dying in the James between Newport News and Hampton on Oct. 20-22.
While some scientists say Pfiesteria emits
a toxin that is harmful to people, there is no evidence that Kudoa represents a threat to public health.
Federal researchers last year identified a fungus as the likely cause of sores found on dying Maryland fish in 1997. Previously, many scientists thought Pfiesteria's toxins caused the sores.
Kudoa, Pfiesteria, the fungus and various bacteria and amoebas may all be plaguing fish in various combinations, and they may all be aided by water pollution, Garman said.
"In my personal opinion, we need to keep Pfiesteria on the list of possible suspects, but it's fairly far down on that list," Garman said yesterday.
Dr. Patrick Gillevet, a George Mason University researcher who helped identify the Kudoa parasite, said, "We've thought for quite some time that fish kills may have been caused by a combination of environmental stress and alternative disease-causing organisms and not by Pfiesteria-produced toxins. These results support our hypotheses."
Others, however, said it's too early to downplay the threat caused by Pfiesteria.
Although fish attackers such as Kudoa and fungi pose little threat to the public, Pfiesteria can sicken people, said Dr. David Goshorn, chief of the living resource assessment program for the Maryland Department of Natural Resources. "It's still a very large concern."
Pfiesteria made national news two years ago when the one-celled creature was blamed for killing nearly 30,000 sore-covered fish in the Pocomoke River, part of the Virginia-Maryland boundary on the Eastern Shore.
About two dozen people in Maryland and five in Virginia complained of memory loss and other problems they attributed to Pfiesteria. The victims later improved.
Maryland and Virginia closed their portions of the Pocomoke after scientists found Pfiesteria on the Maryland side. Maryland officials also closed two other rivers that contained fish they believed to be sickened by Pfiesteria.
Night after night, regional television stations ran pictures of the bloody, dying fish -- almost all an inedible species called menhaden. Still, many people stopped eating seafood, and the federal government responded by issuing millions of dollars in grants for Pfiesteria research.
Tests that year did not find Pfiesteria in Virginia waters. Later, however, researchers reported finding Pfiesteria in the York River and in Mosquito Creek on the Eastern Shore of Virginia.
Late last month, Garman led a team of VCU researchers who found hundreds of menhaden, covered with sores, dying in the James River near Hog Island.
Tests showed Pfiesteria was not in the water. Fish samples were sent to a federal lab, where protozoologist Dr. Thomas Nerad found the fish were afflicted by Kudoa, a strange animal that produces spores like a fungus.
"What we had was a classic Pfiesteria-like event, everything about it was textbook, but without the Pfiesteria. . . . This would have generated a huge panic a couple of years ago," Garman said.
VCU plans to issue a statement today about the Kudoa discovery.
Garman said he hopes to have tests run on specimens collected in Maryland and North Carolina -- fish believed to have been attacked by Pfiesteria -- to see if some actually were afflicted by Kudoa.
v is a well-known parasite in the excrement-rich ponds of fish farms, but it is rarely found in natural waters on the East Coast, Garman said.
Pollution from sewage plants, farm runoff and other sources may provide fertile conditions for fish attackers such as Kudoa, fungi and Pfiesteria to grow, or the pollution may stress fish and make them more susceptible to the organisms' attacks, Garman said.
Cases of sore-covered fish dying in coastal waters are clearly on the rise, Garman said.
"It may be that our coastal watersheds are creating conditions in rivers and bays that are similar to those found in a crowded fish farm," he said.