ROM curator 'very happy' to help identify new species of medicinal leech

You might thinkofleeches as something to avoid.

But the bloodsucking parasitic wormsstill play apart inmodern medicine and researchers like Sebastian Kvistof the Royal Ontario Museum in Torontohave been seeking them out.

Kvist, the ROM's curator of invertebrates, is one of fourco-authors of a report by aninternational team of scientists thatmade thefirst discovery of a new North American medicinal leech species in more than 40 years. Their study was published Thursday in the Journal of Parasitology.

The ROMis home to a leech now considered a memberof the new species. It's no longer alive, but is housed in a jar. Kvist said when he first received the leech a few years ago he knew something was different.

"I was very, very happy that we had them here," Kvisttold CBC Toronto during an interview in his lab.

"It's a good thing to distribute individuals of this species throughout the world in different museums or natural history collections so that we do have a repository of the species around the world should something happen," he said.

A teamled by Anna Phillips of the Smithsonian National Museum of Natural Historyfound the speciesin Maryland in 2015 while investigating genetic variations of leeches. They initially thought the leech they foundwas of a species that had already been identified, but DNA sequencing revealed otherwise.

The 2015 discovery prompted the teamto look for more.

Phillips's teamsearched through marshes and ponds looking for live leeches, but theyalso asked museums to take another look at existing specimens. After analysis, researchers learned that dozens of the new species,namedMacrobdella mimicus, had been preserved in museums for years without scientists knowing they were a different species.

They eventually discovered thenew specieshaslong called the region between the Appalachian Mountains and the eastern coast of the U.S. home.

"We were really excited," Phillips said. "There's four species known and everyone thought these were pretty well characterized. We thought we knew them pretty well."

She said the leeches were never far away the new species were found less than 80 kilometres from the Smithsonian, where she is the parasitic worms curator.

"It just goes to show that there's a lot [of] unrecognized diversity," Phillips said.

Over a two-year period, the team examined 147 of the new leeches, 60 of which came from museums.

As part of the study, Kvist helped sequence the leech'sDNA and compared it with the quintessential North American medicinal leech species called Macrobdella decora. He was able to confirmthe new species.

He said there's a five to 10 per cent difference in DNA between the two species, but the physical differences are best seen under a microscope.

"Those differences are quite minute for non-leech experts, but for us, they're actually quite significant," Kvist said.

He said the discovery allows people to better understand the ecological diversity that surrounds us and the fundamentals of biology knowing whichspecies lives where and how they interact with each other.

"You can't conserve or protect something that you don't know what it is," he said.

Notorious bloodsuckers

Medicinal leeches have been used medically for centuries in various countries, according to Jacalyn Duffin, professor emeritus of medicine at Queen's University.

"They were probably used before writing began," she said.

It was believed ridding the body of bad blood could help cure ailments including headaches, fevers and disease.

They are still used atToronto Western Hospital's combined surgical unit for post-operativepatients.

"It's pretty amazing what leeches are able to do," said April Huang, a nurse educator at the hospital.

Leeches are used on about one-third of patients who have had a finger amputated and reattachedby surgeons, according to Huang.

The leeches help manage some post-surgery symptoms, and can prevent complications. They are also used to facilitate blood flow.

Huang said not only do they suck out congested blood, they can dilate blood vessels to increase blood flow and prevent clotting. Their saliva includes an anesthetic property that produces a numbing effect and has proteins that help with anticoagulation.

Kvist said the discovery of the new species doesn't equate to any concrete changes in the medical field, but it could eventually help patients.

"We're hoping that down the line the knowledge of this new species will help us to find new anticoagulants or new blood thinners that these leeches have in their saliva and that might be of benefit."