Use of molecular probes to assess geographic distribution of Pfiesteria species

We have developed multiple polymerase chain reaction (PCR)-based methods fo r the detection of Pfiesteria sp. in cultures and environmental samples. Mo re than 2,100 water and sediment samples from estuarine sites of the U.S. A tlantic and gulf coasts were assayed for the presence of Pfiesteria piscici da Steidinger & Burkholder and Pfiesteria shumwayae Glasgow & Burkholder by PCR probing of extracted DNA. Positive results were found in about 3% of s amples derived from routine monitoring of coastal waters and about 8% of se diments. The geographic range of both species was the same, ranging from Ne w York to Texas. Pfiesteria spp. are likely common and generally benign inh abitants of coastal areas, but their presence maintains a potential for fis h and human health problems.