Kirsten Jensen, professor of ecology and evolutionary biology at the University of Kansas

For nearly 10 years now, University of Kansas parasitologist Kirsten Jensen has traveled the world in search of new tapeworm species. More than 50 countries and countless gutted specimens later, Jensen has documented her fascination with parasites in a new book, published late last year by the University of Kansas Natural History Museum.

The publication, “Planetary Biodiversity Inventory (2008-2017): Tapeworms from Vertebrate Bowels of the Earth,” describes roughly 4,800 known species of tapeworms, including the more than 200 species discovered by Jensen and her colleagues.

Jensen used a scanning electron microscope at one of KU’s Core Research Labs to capture high-resolution images of the tiny parasites. Most, she says, were less than 5 millimeters long, measuring just a fraction of an inch.

“We can’t even imagine what they might look like,” says Jensen, a professor of ecology and evolutionary biology at KU. “We’re always amazed when we see something completely novel.”

With her collaborator Janine Caira of the University of Connecticut, Jensen has dissected marine creatures in the middle of fish markets, on boats and wherever else they happened to stumble upon potential specimens. The scientists had to work fast in removing the guts of their host animals, as parasites don’t survive long inside dead hosts.

Kirsten Jensen, pictured here in khaki pants and a black tank top, studies a parasite with help from local residents in the Solomon Islands. Jensen, a professor of ecology and evolutionary biology at the University of Kansas, recently published a book of her ongoing research (with Janine Caira of the University of Connecticut) on parasites.

Most of their subjects were sharks and stingrays found in places like Senegal, South Africa, Mozambique, Egypt and Taiwan.

“We just basically move our lab operation into the field and collect whatever we can,” says Jensen, also a senior curator at the KU Biodiversity Institute.

One of her favorites from the ongoing parasite project: seussapex, a new species named for its resemblance to illustrations from Dr. Seuss books. While tapeworms have traditionally been maligned and feared by humans, Jensen says the creatures are much more complex and beautiful (up close, that is) than the misconceptions surrounding them.

“We document 19 different orders of tapeworms, and only two of those have members that parasitize humans, that are relatively well-known to parasitize humans,” Jensen says. “All the others do not.”

What’s more, the animals that commonly host parasites — birds, sharks, stingrays, shrews and catfish — aren’t hurt by the tiny worms, says Jensen, who remains fascinated by the diversity (both in terms of species and the vertebrates who serve as hosts) of parasites.

Jensen’s ongoing project, partially funded by a National Science Foundation grant, estimates there to be about 20,000 species in the world. Many of the 4,800 described in her recent book are on display (in colorized large-scale photographs) at the KU Natural History Museum, 1345 Jayhawk Boulevard. The ongoing exhibit originally opened about five years ago.

On Sunday, Jensen and her colleagues will travel to Sri Lanka, where British scientists last collected and described tapeworms back in 1910. Since then, nearly 200 new species of sharks and stingrays have been discovered in Sri Lanka, and Jensen and her team plan to collect and dissect as many host specimens as possible.

Despite their creepy appearance, these tiny critters don’t pose much of a threat to humans, Jensen says. People usually contract tapeworms by eating raw or undercooked fish or meat.

There’s a simple solution to that, Jensen says.

“As my colleague always so aptly says, cook your food,” Jensen says. “You will not get a tapeworm if you cook your food.”