Parasites change life history of snails

04-22-2014

With 4.5 billion humans infected with parasitic worms, it's no surprise that half of all living creatures are parasites.

While the mere mention of internal parasites may make some queasy, Dennis Minchella finds their unique life- styles and "cleverness" fascinating.

Minchella, a professor of biological sciences and associate dean of the College of Science, became interested in parasites while taking an invertebrate zoology course as an undergraduate student. He enjoyed learning about para- sites' mechanisms for survival and how they can transmit themselves to different hosts.

Coevolution between hosts and parasites is one of the main areas Minchella studies. As hosts develop defense mech- anisms against parasitic infection, the parasites find intelligent ways of adapting against the host's defenses, entering what is known as a coevolutionary arms race.

"Within a coevolutionary arms race, hosts are coming up with ways to thwart their parasites and then their parasites are getting over those obstacles," said Alyssa Gleichsner, a Ph.D. candidate in biology and assistant in Minchella's lab.

Minchella works mainly with schistosomes, parasites which penetrate humans' skin after their larvae complete a stage of their life cycle in snails. Within his lab in Lilly Hall, Minchella replicates the schistosomes' entire life cycle ... minus the human host.

"We have tanks of freshwater snails, and we run (the parasites) through mice, so mice are the vertebrate host," Minchella said. "If you want to study the parasite, you have to be able to have it in a life cycle. It has to be alive and the only way to keep it alive is to keep it cycling through snails and vertebrate hosts."