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Jun 20, 2024 · After a century of speculation, new footage has confirmed that leeches can jump to get around. By coiling their body back, the blood-sucking invertebrates are able to throw themselves forward, potentially towards new prey. Some leeches aren’t just passive parasites but might actively hunt for food.
The medicinal leech is the UK's largest leech species and can grow to up to 20cm (8in) long. They have five pairs of eyes and a sucker containing three jaws and about 100 teeth.
1 day ago · The medicinal leech is the UK's largest leech species and can grow to up to 20cm (8in) long. ... What happened to the young girl captured in a photograph of Gaza detainees.
Feb 15, 2022 · Edwards and 22 others were fatally injured when the plane carrying the United team crashed as it took off from the German city on 6 February 1958. Molly Leech, who died in 2004, was at his...
- Overview
- Where medical leeches come from
- How leech therapy works
- Robotic leeches
Long dismissed as a throwback to the Middle Ages, doctors have been turning to the parasites to help transplant and plastic surgery patients.
Medical leeches at a medicinal leech breeding facility in Biebertal, Germany.
A rare type of cancer called synovial sarcoma landed Ellie Lofgreen at the University of Utah Hospital this summer. Surgeons removed a tumor—the size of a small cantaloupe—wrapped around her knee joint and also cut out a few inches of bone and muscle connected to the knee. They inserted a metal implant in her leg and covered it with a large flap of muscle and skin transplanted from her upper thigh. But a few hours later, the flap began turning purple, a sign, the doctors knew, that the transplanted tissue was dying.
Saving the graft was critical so the medical team proposed a treatment that surprised Lofgreen: leeches.
“I was absolutely floored,” says the 31-year-old Idaho resident. “My initial reaction was, Okay, anything but that.”
Aside from the yuck factor, the use of leeches in modern medicine often surprises patients given that these blood-sucking parasites were long dismissed as quackery. But their use in plastic and reconstructive surgery has picked up since 2004, when the U.S. Food and Drug Administration approved leeches as a medical device to relieve congested veins and restore blood flow in compromised grafts.
Although there are more than 600 species of leeches, including some that don’t suck blood, the European Hirudo medicinalis and Mediterranean Hirudo verbana are most frequently used in medicine. They have three saw-like jaws, each bearing about 100 teeth that the animals use to puncture skin.
For decades, laboratories in several countries including United Kingdom, United States, France, Turkey, and Ukraine have been breeding these medical leeches. Carl Peters-Bond at Biopharm U.K., a company that supplies about half of the medical leeches used in hospitals globally, has been doing this for nearly 30 years. It takes anywhere between a year and two years to raise a leech ready for medical use, he says. The process involves feeding them at three weeks, eight to 10 weeks, and then at four to five months, after which they’re starved for up to two years. “We only ship leeches with an empty gut,” he says.
When a leech bites, it slowly sucks blood and injects compounds like hirudin and calin—present in its saliva—that keep the blood from clotting. Leech saliva also contains histamine-like substances that dilate blood vessels and improve blood flow. Physicians have also used anticoagulants like heparin to prevent blood clots from forming during reconstructive surgeries. But you still need the active sucking of blood, Agarwal says.
Depending on the size of the graft and the degree of congestion, leeching can continue for three to 10 days or more, until the tissue looks “less swollen, less purple, more normal,” Janis says. Patients remain in the hospital while medical staff supervise the process—replacing every engorged leech with a new starved one. Each critter can only be used once and is drowned in alcohol after it has served its purpose.
Over the course of two weeks, Lofgreen had more than 100 leeches drain her dingy-looking tissue. With help from nurses and crowdsourced suggestions via Facebook, her family named each one of these invertebrates. Some of Lofgreen’s favorites included Aleecha Keys, Clint Leechwood, Sir Leech-a-lot, and Queen Laleecha. Every four hours, a nurse would come in and place a new leech, which would suck blood anywhere between 15 to 120 minutes before falling off and landing on her bed. While undergoing the therapy, doctors gave her blood transfusions to replace the lost blood.
But getting the leech to latch on was a struggle sometimes; ensuring it stays where it should was trickier. Initially, nurses used a four-ounce plastic cup, which they inverted and taped onto Lofgreen’s skin to contain the leech. But the critter would often sneak out. The staff then created a barrier using a piece of gauze with a hole where they wanted the leech to attach; they hoped the gauze would discourage it from wandering off to surrounding skin. But that wasn’t foolproof either. What worked best was her mother’s and sister’s watchful eyes. Throughout the day they would take turns watching for rogue leeches and immediately alert the nurses. Lofgreen felt no sensation when these parasites bit into the transplanted tissue, but it pinched sharply when they bit elsewhere. “It was like pins and needles,” she says.
Over time, the part of her tissue that initially appeared dark and necrotic turned light purple and the skin looked more normal. “We had some success with the leeches,” Lofgreen says. But after she returned home, a small section of the flap got infected and had to be removed. The infection wasn’t linked to leeching but rather the result of an open wound. However, she credits the slimy slithering creatures with saving the majority of the transplanted flap.
A study that looked at 277 cases of medical leech use reported a 78 percent success rate. “It’s a very attractive option for flap salvage,” says Ernest Azzopardi, a plastic surgery specialist at University College London in England and co-author of the study. But a lack of robust randomized control trials, the gold standard for evaluating the effectiveness of an intervention, has meant less confidence in using leech therapy.
For years, scientists have been searching for alternatives to leeching. Early attempts date back to the 19th century when leeches were in high demand in Europe and the invertebrates were becoming scarce and thus more expensive. In 1817, Jean-Baptiste Sarlandière, a French anatomist and physiologist, for instance, developed a device called the bdellometer, which drained blood from patients.
Agarwal, for instance, has been working with colleagues at the University of Utah since 2013 to develop a mechanical leech that can deliver an anticoagulant but also mimic the leeches’ suction. The prototype consists of an array of needles that puncture the skin, where a central needle would supply the anti-coagulate heparin to the blood saturated tissue and surrounding needles connected to a pump would suction blood. This thumb pad-sized device would allow doctors to control the volume and rate of blood aspirated, which isn’t possible when using real leeches. For now, the team is trying to perfect the flow of anticoagulant into the tissue where the device is attached.
Although the burn was treated, he developed cancer and died three years later. The complainant had a pre-cancerous condition, before the burn had taken place. When he died, his widow brought a claim against Leech Brain & Co Ltd under the Fatal Accidents Act.
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May 19, 2023 · Irrevocably, leeches became a household name, with health professionals using them as a treatment for everything from cancer to mental health conditions. In the 1800s, British physician Thomas Tanner even wrote that applying them to the anus could be used as a treatment for obesity.
