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Category: Clinical Microbiology
Pfiesteria piscicida and Human Health, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555818418/9781555811686_Chap09-1.gif /docserver/preview/fulltext/10.1128/9781555818418/9781555811686_Chap09-2.gifAbstract:
Presumptive exposure to toxins produced by Pfiesteria piscicida, a small dinoflagellate found in mid-Atlantic estuarine waters, emerged as the cause of a novel human health syndrome of impaired cognition associated with skin rash, headache, gastrointestinal symptoms, and respiratory complaints following fish-kill events in Maryland's Chesapeake Bay in 1997. Dinoflagellates meet their nutritional needs either by photosynthesis (autotrophy), phagocytosis of food sources (heterotrophy), or combinations of these strategies (mixotrophy). Blooms of populations of these and other organisms that affect environmental quality and, at times, human health are often considered collectively under the general topic of harmful algal bloom (HAB). Toxin production by marine and estuarine dinoflagellates is responsible for four human health syndromes. Many fish collected during Pfiesteria-related fish-kill events display aberrant swimming behavior and have diffuse epithelial injury, with hemorrhage and necrosis. No consistent or unexpected abnormalities were found on physical examination. As outlined in this chapter, much remains to be learned about the organism, its presumed toxins, the environmental conditions which promote toxin expression, and the mechanisms by which these toxins might cause disease in humans. At the same time, there is an increasing convergence of data which support the idea of a link between exposure to toxins produced by this and related dinoflagellates and the occurrence of illness in humans.
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Scanning electron micrograph of P. piscicida (toxic zoospore, ventral view). Bar, 1 µm. From H. Glasgow and J. Burkholder, North Carolina State University.
Scanning electron micrograph of P. piscicida (toxic zoospore, ventral view). Bar, 1 µm. From H. Glasgow and J. Burkholder, North Carolina State University.
The Chesapeake Bay and Tangier Sound region (Maryland and Virginia). Fish-kill events associated with human health problems occurred on the Pocomoke, Manokin, and Chicamacomico Rivers during the late summer and fall of 1997. The Chicamacomico River is a small tributary of Fishing Bay.
The Chesapeake Bay and Tangier Sound region (Maryland and Virginia). Fish-kill events associated with human health problems occurred on the Pocomoke, Manokin, and Chicamacomico Rivers during the late summer and fall of 1997. The Chicamacomico River is a small tributary of Fishing Bay.
Characteristic external lesions observed in Atlantic menhaden (B. tyrannus) collected from the Chicamacomico River during a fish-kill event associated with the toxin-producing dinoflagellate P. piscicida. Fish with similar external lesions were observed throughout this region ( Fig. 2 ) during 1997. As noted in the text, histologic evaluation of such lesions has frequently revealed the presence of opportunistic bacterial and fungal pathogens in granuloma formations. Photo courtesy of Ernest Brown.
Characteristic external lesions observed in Atlantic menhaden (B. tyrannus) collected from the Chicamacomico River during a fish-kill event associated with the toxin-producing dinoflagellate P. piscicida. Fish with similar external lesions were observed throughout this region ( Fig. 2 ) during 1997. As noted in the text, histologic evaluation of such lesions has frequently revealed the presence of opportunistic bacterial and fungal pathogens in granuloma formations. Photo courtesy of Ernest Brown.
Percentage of study participants with exposure to Pfiesteria-related fish kill events scoring below the 8th and 2nd percentiles (in comparison with age- and edutcation-matched national normative data) on the Rey auditory, verbal, learning and memory test. grouped by degree of exposure to waterways with Pfiesteria activity.Controls were watermen who worked on ocean waters without potential Pfiesteria exposure. Data are from reference 22 .
Percentage of study participants with exposure to Pfiesteria-related fish kill events scoring below the 8th and 2nd percentiles (in comparison with age- and edutcation-matched national normative data) on the Rey auditory, verbal, learning and memory test. grouped by degree of exposure to waterways with Pfiesteria activity.Controls were watermen who worked on ocean waters without potential Pfiesteria exposure. Data are from reference 22 .