Leeches: How to identify, avoid and remove them

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Key highlights: Leeches, common parasites encountered during outdoor activities like hiking, use tiny sense organs to detect vibrations and heat from potential hosts. While their presence can be unnerving, they’re generally not harmful and can be calmly and safely removed without complications. As most leeches are freshwater animals, hikers should be aware and take precautions, especially when around wet areas.

Except in rare cases, leeches aren’t generally harmful

Outdoor activities like hiking and trail running are great ways to keep fit and healthy. But being outdoors in nature can also welcome parasites like leeches. Those sneaky, slithery critters everyone loves. Have you ever felt that shiver crawl up your back after you pull off your sock and there IT is – thick, black, shiny and fattened on your blood? The next repulsive thought is how to get it off.

Leeches find their host by detecting vibrations and heat with tiny sense organs. So my tip is, tread lightly. Finding a leech on your body can be scary, at least it is for my wife, but there’s really no need to panic. For some reason they tend to avoid me, especially when she is around. I think leeches can smell fear. Later I’ll give you a few tips on how you can calmly and safely remove a leech without pain or complications from the bite. But first, here’s a quick overview of what leeches are and where you are likely to find them.

What is a leech?

Leeches are segmented worms in the Subclass Hirudinea that are usually ectoparasitic. They are bilaterally symmetrical, with thick muscular bodies. Usually they are dorso-ventrally (front to back) flattened and segmented, though the segments are not often seen. Some leeches are long and worm-like, others pear-shaped and broad. Most can vary considerably in shape both between the elongated and contracted state and between the starved and full condition. The body tapers towards the head and has a small oral sucker surrounding the mouth and a larger caudal (tail) sucker at the rear end, except the marine fish parasites, Pisciolidae, which have a larger oral sucker. The anus is on the dorsal surface (top) just in front of the rear sucker.

Leeches usually have three jaws and make a Y-shaped incision. The Australian land leech has only two jaws and makes a V-shaped incision.

Where you will find them

Most leeches are freshwater animals, but many terrestrial and marine species occur. Land leeches are common on the ground or in low foliage in wet rain forests. In drier forests they may be found on the ground in seepage moistened places. Most do not enter water and cannot swim, but can survive periods of immersion.

In dry weather, some species burrow in the soil where they can survive for many months even in a total lack of environmental water. In these conditions the body is contracted dry and rigid, the suckers not distinguishable, and the skin completely dry. Within ten minutes of sprinkling with a few drops of water, these leeches emerge, fully active.

Freshwater leeches prefer to live in still or slowly flowing waters, but specimens have been collected from fast flowing streams. Some species are considered amphibious as they have been observed in both terrestrial and aquatic habitats.

Leeches can be found almost anywhere in Australia where there are suitable damp areas and watercourses although they are absent from the permanently arid areas.

What do leeches eat?

You! Only kidding. Leeches feed as blood sucking parasites on preferred hosts. If the preferred food is not available most leeches will feed on other classes of host. Some feed on the blood of humans and other mammals, while others parasitise fish, frogs, turtles or birds. Some leeches will even take a meal from other sanguivorous leeches which may die after the attack.

Are leeches dangerous?

The presence of hirudin in the wound following a leech bite may cause oozing to continue for several hours. Although inconvenient, blood loss is not significant. Gut bacteria can cause wound infection. There may also be a delayed irritation and itching after a bite. There appears to be no support for the theory that mouthparts left behind after forced removal of the leech causes this reaction.

Can leeches transmit disease?

There is no evidence to suggest that they do. The presence of trypanosomes in the gut of jawless leeches has been noted, but jawed leeches do not appear to be hosts. Trypanosomes cause the African sleeping sickness in humans. Leeches transmit trypanosomes that infect fish, crocodiles and even platypus, but none of them are dangerous to humans. Allergy to leech bite has been reported. Medical opinion should be sought, depending on the severity of the reaction.

Here’s some tips to keep leeches away

  1. Wear protective clothing: Leeches can’t bite through thick and tight-fitting clothing, so wearing long-sleeved shirts and pants can help protect your skin.
  2. Use a natural repellent: Applying a natural repellent (such as Oil of Lemon Eucalyptus) on your skin won’t harm leeches and can help keep them away.
  3. Avoid areas with standing water: Leeches are often found in damp areas, so try to avoid walking near standing water or wet vegetation.
  4. Use salt: Sprinkling salt on the ground around you can deter leeches as they do not like salt.
  5. Check your body regularly: If you are in an area where leeches are prevalent, make sure to check your body regularly for any attached leeches. The sooner you remove them, the less blood they will have ingested, and the less risk of infection.

It’s important to note that leeches are not harmful to humans in most cases, and they can even be used in medical treatments. However, if you are concerned about leech bites or have any other health concerns, it’s best to consult with a medical professional.

How to safely remove a leech

This is the part I know you have been waiting for.

Your first step in removing a leech is finding it. If you spot a leech on your skin, check the rest of your body to see if any more have attached themselves to you. Once you find a leech, you can begin to safely remove it.

The basic leech removal steps are:

  • Locate the head and mouth. A leech’s head is smaller and slimmer than the rest of its body. Look for the narrowest part of the leech to locate its mouth. This is usually the part attached to your skin.
  • Pull the skin under the leech taut. Use one hand to gently pull your skin under the leech until it’s taut.
  • Slide a fingernail underneath the mouth. Gently slide a fingernail under the leech’s mouth to separate it from your skin.
  • Flick the leech away. Use your fingers to flick the leech away before it reattaches.
  • Clean the wound. Clean your wound with rubbing alcohol or a first-aid cleanser to help avoid infection.
  • Bandage your wound. You’ll see a lot of bleeding when you remove the leech. Clean the wound and then use a sterile bandage to cover it.
  • Change the bandage frequently for the first few hours until bleeding stops.

You can also try these alternative methods for removing a leech:

  • Using a piece of paper or a credit card instead of your fingernail. For this method, you’ll follow all the same steps as above, but you’ll slide a thin piece of paper or a credit card under the leech’s mouth instead of your finger.
  • Letting the leech fall off naturally. Usually, this can take about 30-45 minutes. You can wait for the leech to detach itself when it’s finished feeding, especially if you’re having trouble removing it. If the leech does not fall off for a long time or attaches to a hard to reach area, having it medically removed is the best course of action.

Removing leeches from difficult locations

Leeches will sometimes attach to hard-to-reach areas, like your ear canal, nose, eyes or mouth. This can make it difficult to use the above methods for removal. If this happens, try one or more of the following:

  • Use rubbing alcohol or hydrogen peroxide. To remove a leech from your mouth, gargle with alcohol or hydrogen peroxide for about 30 seconds. Swish the alcohol or peroxide in your mouth like mouthwash, then spit it out. Check to see if the leech comes out with it.
  • Puncture the leech. Leeches can grow up to 10 times their original size when they’re feeding. Sometimes, this can cause them to block an area like your nose or ear. Use a sharp object to pop the leech, killing it and making it easier to remove.

In some cases, the removal method will depend on the location the leech attaches to and may need the help of a medical professional to remove. Leeches that attach internally may require surgery to remove. This can happen if a person swallows contaminated water.

What not to do

Do not remove a leech using any of the following methods. These can cause the leech to vomit blood into your wound and increase your risk of infection:

  • salting
  • fire
  • shampoo
  • bug repellant
  • pulling the leech

Final notes

Finding a leech on your skin can be alarming. However, except in rare cases, leeches aren’t generally harmful. You can carefully remove a leech by using your fingernail or a sheet of paper to separate the leech’s mouth from your skin. Don’t use methods like salting, burning, or drowning to remove a leech, as these can lead to infection. Contact a medical professional if you’re unable to remove a leech, experience any signs of infection, or have an allergic reaction.

If you want to know how to keep other blood sucking insects such as fleas, fly’s, mosquitoes, and the arachnid tick away, you can find out here.

Some of this information courtesy of the Australian Museum

About the Author

Author Image
Darren Edwards is the founder of Trail Hiking Australia, an avid bushwalker, and a dedicated search and rescue volunteer. With decades of experience exploring Australia's wilderness, Darren shares his passion for the outdoors, providing practical advice and guidance on hiking safely and responsibly. He was interviewed on ABC Radio and ABC News Breakfast to discuss bushwalking safety, highlighting his commitment to promoting responsible outdoor exploration.

69 thoughts on “Leeches: How to identify, avoid and remove them”

  1. I find leeches quite amusing. Maybe it’s my sadistic side coming out but I find it funny how such tiny creatures can create so much fear.

    • Trail Hiking Australia screaming like a baby then use a card. Eg like an old credit card. No salt or alcohol as they vomit into you. Ew

    • Trail Hiking Australia I always carry a survival knife and multi tool when out hiking. I don’t recommend it but you can use the blade of the knife scrape it off. If it hasn’t yet fully attached, finger nails work fine. Then a dab of betadine to minimize any infection.

    • Trail Hiking Australia I take them off with my fingers, roll them in a ball in the palms of hands and flick them away. I was in the northern Rivers before the huge flood in Lismore. It rained for 6 out of 7 months prior so many leeches. I just disinfect where they had attached.

      • Sue Evans I used to carry salt too until I read a heap of info that said it can make them vomit into you and cause infection. Never had that happen but I don’t carry salt anymore just in case.

    • Trail Hiking Australia taking a friend with long nails! Worked for the little sucker who took a lunch break on my eye ball 😬
      What also worked for this particular occasion was resilience, trust and a touch of bravery

      • Cassie Pronk I’ve only walked with you a couple of times, but I was there that day. Whenever leech conversations come up we always bring that one up 😧

      • Cassie Pronk Oh, that’s awful for you. Perhaps if you could do mind speak, keep reminding yourself they are actually harmless. Carry saline viles, that’s what they recommend for the eyes. Not that you’d be unlucky enough to have that happen twice. But who knows😬

  2. I usually panic at least initially,after feeling a mild sensation from the leech locking on,then I usually just rip them off!! Not best practice I know!!

  3. Okay. Leeches are my pet topic for civvie hikers. Having spent a significant amount of time traipsing about (and lying on the ground) in tropical jungles and rainforests, I’ll say that prevention is waaaayyyy better than cure.

    For a day hike, if you’re expecting leeches, make sure you treat your shoes and pant legs with your favourite insect repellent (Bushman’s Heavy Duty Spray is my go to). This keeps them climbing UP your legs. Make sure you wear a wide brim hat and treat that with repellent, wouldn’t hurt to treat your neck and shoulders too. Yes. I’ve had leeches literally throw themselves off trees (airborne assault) and rain DOWN around my team, on the off chance of landing on something warm and full of blood.

    If you MUST wade through an infested, stagnant tropical stream, good luck…they will find their way into your crevices. Here is where I suggest you bring your favourite insect repellent and go to town when you get to a convenient spot to drop your pants, check your socks, boots, seams and even your pockets (there is a reason why some of us literally went ‘commando’). Make sure you take the time to do another leech check later down the trail. You might have missed one or two.

    TBH you’re better off just getting through all the water obstacles (low ground) and doing a thorough leech check once you get to high ground and don’t anticipate any more water crossings.

    I do have a few methods for getting them off if they are attached (there are quite a few good suggestions here—not sure if I take a hunting knife to my groin but hey, it ain’t stupid if it works) but depending on how long and how deep the wound is, treatment varies. Really deep open leech wounds take forever to clot and you really want to make sure a bloat fly doesn’t lay her eggs in you while you’re still mucking about in the jungle.

    Now. Here’s one thing I was never game to try. Apparently, some more progressive types (during the Vietnam War) would put on nylon pantyhose under their pants. Leeches aren’t strong enough to chew through nylon. If this is something you’re thinking of trying, let us know how you go.

    PS They do make leech proof under garments now, so maybe you don’t need to bother your mum for a pair of her old nylons.

  4. I would use hand sanitiser. I feel bad for the leeches to be honest, they’re just doing their own thing and are mainly harmless. But having had an infection from one a few years back that was pretty unpleasant and required a course of antibiotics, these days it’s me or the leech!

    I find bug spray on shoes, socks and lower pants can also help in deterring them. I used to carry a small spray bottle with a home made mix of water and various essentials including the citrus ones you mention.

  5. i literally have a fear of them… i work on a farm where this a bushy leech area and my boss knows l have a geninue fear of them, so she kindly goes in there for me… I think its the fact that they can get into area where you don’t want them that l don’t like. My boss has had them in her eye, and one count she had 22 on her….

    • Renee Murden Reminds me of the time I had one hanging off my neck for 4 hours…it was the size of a broad bean by the time I realized. Of course, my buddy just looked at me and said, “Yeah, saw that 4 hours back…but since we’re pushing to get to the objective and losing daylight, I figured you wouldn’t want to stop to take care of it.”

      After I dealt with the leech, I bled into my shirt half the night. 🙈

    • Renee Murden I have a sneaking suspicion that they can sense fear and are attracted to it. My wife can’t stand them and on one hike, we counted 42 on her feet and you could see then crawling along the ground towards her. I didn’t have any on, or near me. We are totally the opposite with mosquitoes though.

      • Trail Hiking Australia I’m sticking with ice water 😁

        Actually, it really is body heat. They will head towards the hottest heat source. We discovered this one afternoon when we stopped to boil some stream water. The leeches ALL fast crawled past us, straight up the gas burner and danced around the flame. It was weird AF.

  6. I had a leach the other day on the second knuckle of my big toe (NSW south coast), put a bit of salt on it and thought nothing of it. On day two my entire foot and ankle were swollen. It took 4 antihistamines to bring the swelling down. I usually have a bad reaction to ticks, I’ve had over a hundred over the years, it’s seems leaches are going the same way for me now

    • Rod Riguez oh that doesn’t sound good. I saw someone else commented they had an allergic reaction. I’ve read that putting salt on them can cause them to vomit I to the wound, causing an infection.

      • Trail Hiking Australia I’ve been using salt on them for 45 years. Never had a problem before. I’m guessing some sort of auto immune response due to over exposure, or I’m just old and dying

      • Rod Riguez id always used it too and have never had issues. Might be an over exposure thing. I have that with bull ant bites now

  7. I’ve just developed a reaction to them. The last two leeches I fed left me with bites that required 24/7 icepacks for a whole week. Any pro-tips from anyone on aftercare from others who react?

  8. In outdoor ed world we get them off the kids with hand sanitizer which nukes them straight away. It causes them to let go from the mouth.

    The knife flicking method is not recommended as it can cause more of a bite wound as the leech can detach at the mouth resulting in the mouth remaining attached to your skin.

    Leeches have an anticoagulant in their saliva which prevents blood from clotting, hence, the bite site will most likely bleed a lot. Clean up the blood and clean the site with steri wipes to prevent infection.

    They’re just fact of life in my line of work unfortunately. I flicked 2 off me last week

    • Samir Sawant I used to have salt in the post as a recommendation. That was until people called me out for it a while ago saying it’s not a recommended approach. I think use what works for you.

  9. Don’t remove! The reaction is much worse when leeches removed compared to letting them finish their dinner and drop off naturally

    • Amanda Warriner I had one on my neck that I didn’t know about once. Seemed he was never going to let go, it was huge by the time it had finished gorging itself. My contribution to the leech world I guess.

      • Trail Hiking Australia funny you should say that, i had one on the back of my neck last week! I found it by rubbing my neck, he was already well fed and had ended up tangled in my hair. It definitely took its fair share of my blood, but a lot less itchy rhen the bites on my legs and under my shirt

    • Patrick Wark I don’t think it is recommended. Although I’m guilty of trying in the past. There’s a lot more awareness now about not actually killing them. Plus I have hairy legs so it’s probably not the safest option for me.

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