The Harm of Blood-Sucking Leeches to the Human Body and Methods of Prevention and Treatment

Since ancient times, it has been universally acknowledged that leeches bite people and suck blood, causing harm. That leeches are used as medicine to treat illness is also a consensus among physicians. Only regarding the toxicity of medicinal leeches do views differ, and it has long been a subject of controversy. In order to effectively bring out the medicinal value of leeches, one must have an accurate understanding of their medicinal properties.

The harm of blood-sucking leeches to the human body and prevention and treatment: When blood-sucking leeches suck blood, the hirudin they secrete, no matter how much is injected, can resist blood coagulation, causing the bite site to bleed incessantly and exposing humans and animals to bacterial infection and illness. 1. Symptoms of poisoning (1) Local symptoms: slight itching, pain, and incessant bleeding. The attachment site appears papular, commonly on the popliteal fossa of the lower limbs, the nasal septum, esophagus, anus, vagina, and the male urethra. When leeches parasitize body cavities, secondary infection can lead to wound ulceration and suppuration. (2) Systemic symptoms: generally not obvious. If multiple bites cause relatively heavy bleeding, there may be anemia symptoms such as dizziness and palpitations. 2. Rescue (1) Removing the leech: 1 After discovering a leech bite, one should first try to remove the leech from the human body, but must never forcibly pull it with the hands, lest the leech be torn apart and its sucker remain in the wound, which would instead cause incessant bleeding and readily lead to secondary infection and corrosive ulceration. 2 When a leech bites a wounded part of the human body, the simplest method is to pat the wound with the hand so that the leech falls off by itself, or to wash the bitten area with irritating substances such as vinegar, saturated salt water, ethanol, tobacco oil, or chili water, so that it comes off by itself. 3 When a leech bites the nasal septum or upper respiratory tract, one should promptly go to the hospital and, after anesthesia, carefully remove the leech. Or use 1% ephedrine solution to shrink the inferior nasal concha, or spray 1%-2% dicaine into the nasal cavity to reduce the patient's pain, then remove it with forceps. For bites in the pharynx or trachea, under a bronchoscope, it can be gently removed with forceps. There are also reports of using clear water to lure out leeches that have entered the nasal cavity. 4 When a leech parasitizes the esophagus, one may orally take concentrated salt water to make the leech fall into the stomach, where it is digested by gastric juice. If it parasitizes the urethra, bladder, or other such places, concentrated salt water can be used for irrigation. (2) Hemostasis: After the leech is removed, bleeding from the wound is commonly seen at the bitten site; hemostatic cotton can be used for compression to stop the bleeding, or 2% ephedrine solution and 1:1000 adrenaline cotton balls can be used for hemostasis, and hemostatic agents should be used when necessary. (3) Dressing: After the wound is washed with an antiseptic, apply a sterile dressing. (4) Prevention of tetanus: To prevent tetanus, depending on the circumstances, a single subcutaneous or intramuscular injection of refined tetanus antitoxin (abbreviated as “refined tetanus antitoxin”) of 1500—3000 units may be given. The dosage for children is the same as for adults. For severe injuries, the dosage may be increased by 1-2 times. After 5—6 days, if the risk of tetanus infection has not been eliminated, the injection should be repeated. Before injection, an allergy test must first be done; if there is no allergic reaction, inject directly under close observation. If there is an allergic reaction and injection is still required, it must be given under a doctor's guidance. 3. Prevention In life, people often “turn pale at the mention of leeches.” In fact, blood-sucking leeches are a minority; most do not suck blood. To prevent blood-sucking leeches from causing unnecessary harm to people, when active in places with many leeches, one should still take extra precautions. The simplest method is not to drink unboiled water, and when passing through paddy fields, swamps, or valleys, wear high-top shoes and boots, or tie the trouser cuffs tightly to prevent leeches from climbing onto the legs. When one must go barefoot, apply Vaseline, mosquito repellent oil, or thick soapy water to the legs, reapplying once every 3—4 hours. Case of leech injury: A male, 16 years old, on May 30, 1977, while fishing in a pond, felt itching of the penis and saw a leech penetrate into the urethra, so he was hospitalized for treatment. After routine disinfection, a urinary catheter was inserted and irrigation was performed with 0.9% sodium chloride solution, each injection of 50—80 mi, with a total volume of 500 ml, and the extracted fluid was all blood-colored; then 80 ml of 0.5% procaine was injected, and 15 minutes after the catheter was removed, a leech was automatically passed in the urine; after intramuscular injection of vitamin K3, the hematuria was controlled after persisting for 3 days.