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Project with Bernard Fried, Kreider Professor Emeritus of Biology, explores factors that kill food-borne parasites

Biology major Robert Peoples ’08 (Bear, Del.) and Bernard Fried, Kreider Professor Emeritus of Biology, have published research on ways to kill cysts of food-borne parasites in the Journal of Parasitology.

They have been working together since 2005 examining trematodes, debilitating and sometimes lethal, parasitic flatworms common in third world countries. The work has specifically looked at Echinostoma caproni (E. caproni) an Egyptian species of trematode that is not dangerous to humans, but is related to numerous malignant species that infect humans and livestock in places with poor sanitation.

When these worms are in the encysted stage of development, in which they are concealed within a cocoon-like cyst, they often attach to aquatic vegetation, mollusks, or crustaceans that are consumed by humans and animals as food. Peoples also presented this research at the 83rd meeting of the Pennsylvania Academy of Science in April 2007.

“When an animal such as a bird or mammal eats the vegetation or an aquatic animal that contains cysts, it becomes infected,” explains Peoples. “[Once consumed,] the worm hatches out of its protective cyst, finds a favorable spot in the animal’s or human’s gastrointestinal tract and attaches to the lining of the gut. There, it feeds on bodily mucus, fluids, and potentially bits of the host’s food present in the tract. The malignant form of these worms can weaken and potentially kill their hosts if they are present in large enough numbers.”

Peoples and Fried examined physical and chemical factors that kill the cysts that contain these worms. They subjected the cysts of E. caproni to different chemicals and physical stresses, such as drying out, freezing, and boiling. Next, they used an artificially derived combination of enzymes and compounds to mimic as best as possible the conditions found within an animal gut in order to determine if the previous treatment had killed the cysts.

“If the worms came out of their cysts upon treatment with the trypsin-bile medium, then the physical or chemical test had failed at killing the cyst,” Peoples explains. “If no worm came out of the cyst upon treatment with trypsin-bile, then it was assumed that the treatment had effectively killed the cyst.”

Fried, who has been researching trematodes and trematodiases for nearly 50 years, describes Peoples as a wonderful student to work with.

“[Peoples] is bright, hard working, meticulous in his handling of the experimental material we work with, and 100 percent dependable and reliable,” says Fried. “He is very good with experimental design and can now manage many of the experiments we do by himself. He has worked closely with me for almost two years and I now consider him more as a colleague than a student.”

Peoples plans to pursue his interest in parasitology as a career. He has applied to graduate programs in marine parasitology at various domestic and international institutions and describes working with Fried as an honor in and of itself.

“[Fried] is one of the kindest individuals I have ever met,” says Peoples. “He has been truly generous toward me in allowing me to take part in his research and trusts me with responsibilities that I do not think many other undergraduates are granted.”

Peoples is currently researching methods for killing another species of food-borne flat worm parasite similar to E. caproni, called Zygocotle lunata, also under Fried’s guidance. He plans to present their findings this year at the 84th meeting of the Pennsylvania Academy of Science.

Peoples has been a volunteer with Landis Community Outreach Center and a Teacher’s Assistant for general biology labs. Currently, he is a member of Phi Kappa Psi Fraternity and has worked as a lifeguard at the Ruef Natatorium for the past two years.

  • Biology
  • Undergraduate Research
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