Leeches – and how to stop them becoming hitch-hikers

Submitted by Chris Shattock on Thu, 09/06/2011 - 18:08

In our tall timber is a lovely place to walk, but being temperate rain forest it can be very wet and leeches love these conditions.

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.

They find their hosts through ground vibration caused by them, and it is believed they also sense one’s body heat. I’ve been with a group sitting quietly having lunch when we noticed an army of leeches inchworming their way toward us. Was it the champing of our jaws, or our body heat that was attracting them?

Walkers usually see them on their boots, climbing up toward tastier morsels. However, if the foliage is wet, they’ll be sitting in the trees, waiting to drop in for dinner.

So with that background, what is the best way of avoiding spilling one’s blood in battle? I’ll give you my method first, and then give you more authoritative advice from a previous article on the subject.

Going on the idea that prevention is better than cure, before going into a leech area, I use a strong insect repellent on:

  • Bare feet and legs up to my knees.
  • All exposed skin.
  • Wrists and neck, which are places they can get under one’s clothes.
  • On boots (easiest with a spray-on repellent).

Don’t believe that tucking trousers into socks will prevent them. It helps, but when they’re skinny they can get through the knit of socks onto your skin. I wear little “Sock Guard” gaiters (available in hardware stores) and spray the inside of them, so there is a real atmosphere of repellent from my legs and the gaiters to make getting to my socks unattractive.

Since using this method I’ve had no trouble with leeches. Giving a leech a squirt of repellent makes it roll into a little ball and let go of anything it’s attached to.

One last tip: always inspect your pack for leeches if it has been on the ground during a break. It will be warm from your back, so it will tend to attract them.

Most people survive leech bites without knowing they’ve been bitten and with no after effects apart from bloody clothes. However, it is possible for the bite to be infected by bacteria on the skin or from the leech’s stomach. Some people develop allergies to them, and some develop cellulitis, which had one of our members in hospital on antibiotic drips.

I’ve used some of Max Sherlock’s excellent talk on leeches (attached), and to follow is an article which was first published in the Melbourne Bushwalkers July 2007 newsletter.

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