Sarah L. Poynton, PhD

Sarah L. Poynton, PhD

Associate Professor

Miller Research Building, Suite 855




B.Sc. (Hons)
Fellowship in Aquatic Parasitology
Fellowship in Veterinary Parasitology
University of Southampton, England
University of Southampton, England
Department of Fisheries and Oceans, NS, Canada
Armed Forces Institute of Pathology, Washington DC



Dr. Sarah Poynton has broad expertise in animal parasitology, with a research focus on: (i) pathogenic parasites of aquatic animals, particularly those in captivity (ranging from aquaculture to aquaria), and (ii) the diplomonad flagellates, Spironucleus and Giardia, significant pathogens of animals and humans. Her work on characterization of metazoan parasites in tissue sections is embodied in the standard reference book, Gardiner and Poynton “An Atlas of Metazoan Parasites in Animal Tissues”, and her work on parasite morphology and ultrastructure has resulted in the description of one new genus and multiple new species of protists infecting cephalopods, fish and cetaceans.

As the recipient of Visiting Professorships from the National Science Foundation (USA) and the German Research Foundation, Dr. Poynton has pursued research nationally and internationally, particularly in Berlin, Germany, and Oslo, Norway. Dr. Poynton has established collaborations with many institutions, including the National Aquarium in Baltimore, the Food and Drug Administration, and the Food and Agriculture Organization of the United Nations (FAO (UN)). For the latter, Dr. Poynton has served as a consultant, and an invited participant in the Expert Workshop on “Global Review on Status and Trends in Aquaculture”, and “Prospective Analysis of Future Aquaculture Development”.

Within the Department of Molecular and Comparative Pathobiology, Dr. Poynton provides training and diagnostic support in parasitology.

Her secondary expertise in writing is evident in the courses she teaches in scientific and biomedical writing, including for the Department of Art as Applied to Medicine, Doctoral Diversity Program, Graduate Training Program in Clinical Investigation, Office of Faculty Development, and the Professional Development and Careers Office. Dr. Poynton has also initiated and taught new courses in scientific writing in Germany, the Philippines, and China.

Dr. Poynton currently serves as the Branch Officer for the USA for the European Association of Fish Pathologists.


Current Research

Dr. Poynton’s research investigates host-parasite interactions, life cycle, and behavior in piscine Spironucleus species. Of particular interests are functional domains, multi-functional flagella, adaptions for increasing transmission, and individual and community behavior of the trophozoite stage. The practical applications of studies on cultured organisms can include discovering novel approaches to treatments. 

Dr. Poynton is also part of a team using Spironucleus and Giardia species as model organisms in which to test novel therapies for intestinal parasites.


Selected Publications

  1. Hadfield CA, Poynton SL, Clayton LA, Romero JL, Montali RJ. KUDOA SP. (Myxozoa: Multivalvulida) in skeletal muscle of captive bullnose eagle rays, Myliobatis freminvillei (Rajiformes: Myliobatidae). J Zoo Wildl Med. 2014;45(4):896-905.
  2. Poynton SL, Dachsel P, Lehmann MJ, Steinberg CW. Culture of the cladoceran Moina macrocopa: mortality associated with flagellate infection. Aquaculture. 2013; 416-417:374-379.
  3. Reimschuessel R, Gieseker C, Poynton S. In vitro effect of seven antiparasitics on Acolpenteron ureteroecetes (Dactylogyridae) from largemouth bass Micropterus salmoides (Centrarchidae).. Dis Aquat Organ. 2011;94(1):59-72.
  4. Saghari Fard MR, Weisheit C, Poynton SL. Intestinal pH profile in rainbow trout Oncorhynchus mykiss and microhabitat preference of the flagellate Spironucleus salmonis (Diplomonadida). Dis Aquat Organ. 2007;76(3):241-9.
  5. Fard MR, Jørgensen A, Sterud E, Bleiss W, Poynton SL. Ultrastructure and molecular diagnosis of Spironucleus salmonis (Diplomonadida) from rainbow trout Oncorhynchus mykiss in Germany. Dis Aquat Organ. 2007;75(1):37-50.
  6. Helke KL, Cooper TK, Mankowski JL, Poynton SL. Disseminated visceral coccidiosis in Indo-gangetic flap-shelled turtles, Lissemys punctata andersonii. J Wildl Dis. 2006;42(4):788-96.
  7. Helke KL, Poynton SL. Myxidium mackiei (Myxosporea) in Indo-Gangetic flap-shelled turtles Lissemys punctata andersonii: parasite-host interaction and ultrastructure. Dis Aquat Organ. 2005;63(2-3):215-30.
  8. Poynton SL, Fard MR, Jenkins J, Ferguson HW. Ultrastructure of Spironucleus salmonis n. comb. (formerly Octomitus salmonis sensu Moore 1922, Davis 1926, and Hexamita salmonis sensu Ferguson 1979), with a guide to spironucleus species. Dis Aquat Organ. 2004;60(1):49-64.
  9. Poynton SL, Whitaker BR, Heinrich AB.  A novel trypanoplasm-like flagellate Jarrellia atramenti  n.g., n.sp. (Kinetoplastida: Bodonidae) and ciliates from the blowhole of a stranded pygmy sperm whale Kogia breviceps (Physeteridae): morphology, life cycle and potential pathogenicity. Dis Aquat Org. 2001; 44: 191 - 201.


View complete list of publications on PubMed.