Pfiesteria - Symptoms & Treatment

Pfiesteria is the name of a dinoflagellate. It occurs naturally in the Chesapeake Bay in at least 24 known life stages. All but four stages are harmless. Under certain conditions, populations may suddenly increase (bloom) and change into one of the four toxic life stages. The Pfiesteria cells then emit toxins that stun fish and dissolve their scales and skin, enabling them to feed on the fish and cause deep ulcers (lesions). Pfiesteria occurs primarily in North Carolina, but has been reported in the Chesapeake Bay and its tributaries. The Pfiesteria genus includes two species, Pfiesteria piscicida and Pfiesteria shumwayae , that reportedly share a similar feeding strategy and life history. These two species, described as members of the "Toxic Pfiesteria Complex" (TPC), reportedly cause ulcerative lesions in fish, fish-kill events, and human health impacts in East Coast estuaries. Pfiesteria is potentially a problem only at certain times of the year and in only some locations. There are many kinds of microorganisms, other than Pfiesteria, which may cause human illness. People should avoid swimming or recreating in waters where fish are dead, dying or have sores. There is ongoing research on whether Pfiesteria affects seafood, so we really don't know if it has an effect on the quality of seafood. Until that research is completed, you should not eat seafood with bleeding sores or peeled skin.

Pfiesteria piscicida is a microscopic, polymorphic organism that belongs to a group of single celled, free swimming phytoplankton called dinoflagellates. Although many phytoplankton photosynthesize to generate the energy they need to survive, Pfiesteria does not it is more animal-like in that it consumes other organisms such as bacteria and algae. It can transform in and out of the following stages within a matter of minutes flagellated, amoeboid, and cyst. In the flagellated stage Pfiesteria is powered by two tiny flagella that resemble tails. The cyst stage lies dormant in the bottom sediments of estuaries and rivers. Pfiesteria is a remarkably hardy organism that can survive over a wide range of temperatures and water salinities. For most of its life cycle Pfiesteria is a nontoxic predator, feeding on bacteria, algae, and other small organisms. When schools of fish are present, Pfiesteria occasionally responds with a quick release of biotoxins into the water. These chemicals stun or kill the fish, which allow the Pfiesteria to feed on the injured skin, blood, and dying tissue. Pfiesteria appears to thrive in nutrient-rich waters. That's why it could be a problem in Delaware's Inland Bays. In those areas, there are too many nutrients going into the bays from a variety of sources including runoff from developed areas, lawns, golf courses, farms and failing septic systems and discharges from wastewater treatment plants.