When it comes to leeches, many people instinctively react with dislike, fear, or even horror. However, as an outdoor enthusiast, it’s essential to have a correct understanding of leeches and learn to coexist peacefully with them.
Leeches, also known as horse leeches or medicinal leeches, belong to the class Hirudinea in the phylum Annelida. There are about four to five hundred species worldwide, with nearly a hundred found in China. They are broadly categorized into water leeches and land leeches.
Water leeches, commonly referred to as water horse leeches, have a flattened spindle-shaped body with numerous segments. Their back is slightly elevated, while the ventral side is flat. The front end is pointed, and the rear end is blunt and round. They possess two suckers, with the rear sucker being larger and exerting more suction.
Land leeches, also known as grass leeches or terrestrial horse leeches, inhabit damp forests, bamboo groves, or areas with decaying wood and leaves. They have a subcylindrical body that gradually tapers from tail to head. The central part of the front sucker serves as the mouth, equipped with three Y-shaped muscular jaws. Each jaw has a row of small teeth along its longitudinal ridge. The rear sucker exhibits distinct radial ribs, and the anal region features a three-lobed, ear-shaped projection.
Common Misconceptions and Facts about Leeches:
- Myth: Leeches are virtually indestructible.
- Fact: There are myths about leeches exhibiting remarkable resilience, such as surviving being cut in half or being dried in the sun. In reality, only under specific conditions can a leech potentially regenerate when cut, and other claims are mostly unfounded.
- Myth: Leeches target specific body parts for entry, such as the brain or genitals.
- Fact: Most of these ideas are created to frighten children away from leeches. Leeches, like other annelids, breathe through their skin and need a moist and oxygenated environment. They do not typically enter the human body, except through naturally ventilated openings like the nostrils and throat.
- Ecological Concerns:
- Leeches play a vital role in ecosystems, contributing to nutrient cycling and serving as an indicator of environmental health. However, their habitats are shrinking due to the overuse of pesticides and fertilizers, as well as pollution from industrial and agricultural activities.
Preventive Measures and First Aid:
- Preventive Measures:
- Apply mosquito repellent, mentholated oil, medicated oils, camphor oil, honey, or anesthetic solutions (e.g., 1% lidocaine, 2% lidocaine) to exposed skin areas, especially hands, neck, and legs, to deter leeches. Spraying clothing with these substances is also beneficial.
- When camping, choose a tent location in dry and open areas. Scatter sulfur powder around the campsite or burn sulfur before setting up camp to create a smoky environment that repels leeches.
- Handling Leech Bites:
- If a leech enters the nose, remain calm. Do not forcefully pull it out. Instead, instill honey, vegetable oil, or anesthetic drops (e.g., 1% lidocaine, 2% lidocaine) into the nostrils, and the leech will likely detach on its own.
- If bitten, gently tap the leech; it will release its grip. Alternatively, use a flat, blunt tool, like a fingernail, to lift the front sucker’s edge, releasing the leech.
- After leech removal, wash the wound with soapy water, apply a purple medicine solution or iodine, and, if bleeding persists, sprinkle Yunnan Baiyao or hemostatic powder on the wound before bandaging.
- In case of infection, cleanse the wound, remove any contaminated blood, and disinfect with a solution of baking soda or clean water. Apply iodine, alcohol, or mercury red ointment for additional disinfection.
Medicinal Uses: Leeches have significant medicinal value. Extracts from dried leeches can treat conditions such as strokes, hypertension, blood stasis, amenorrhea, and injuries. Leech therapy has shown efficacy in preventing cardiovascular diseases and exhibiting anti-cancer properties. With the decline of wild leech populations, there is a growing demand for artificial leech breeding.
It’s worth noting that leeches, despite being non-toxic, should be handled with care to prevent infection. Understanding their behavior and adopting preventive measures enables outdoor enthusiasts to enjoy nature without unnecessary concerns about leech encounters.