This concludes the ‘Limatik’ Encounters series of short essays or posts, inspired by questions during and after that interview as Resource Person in the ‘Limatik’ (Land leech) segment during one episode of the GMA7 TV show “Kapuso Mo, Jessica Soho” or KMJS.
What happens when leeches bite humans or other animals? Do they have negative effects on their ‘victims’ or as ‘blood donors’?
We have already mentioned that their saliva contains hirudin, an anticoagulant that prevents clotting and ensures that the leech gets full with its needed blood meal. However, apart from the wound they leave and possible secondary infection, there are no other known negative effects. Nevertheless, there have been reports of persons with severe allergic reactions as well as a slight feeling of itchiness when the blood that oozed out of the wound starts to dry or clot. Bites near or in the eyes are dangerous. Bites in the eyes have been reported by campers and hikers during seasons when their populations are at peak.
When a person is bitten by a land leech, washing with soap and clean water is the best first aid, but not for the eyes, if there is ready access to these two. Plain clean water for the eyes will do, but some eye doctors recommend a mild salt solution. On ordinary skin, alcohol (isopropyl or ethyl) and/or ‘betadine’ may be the next best if clean water is far. After that first aid, and there is still bleeding, press the sides of the wound or raise the affected area when that is possible. During some of our fieldwork in certain areas, our guides who were members of Indigenous Peoples there did not mind the leeches, they just let them be, so to speak, and seem to not mind the leeches attaching to their legs, feed, and drop when full. Leech bites are no big deal.
The best way to avoid leech bites is to wear fine nylon stockings. The elastic nylon fabric supposedly make it difficult for the leech to reach the skin. I and some of my friends have also tried mosquito repellant lotion (not citronella oil). Either major brand helps repel land leeches but lasts only a few hours and hikers may apply the lotion again. It may also help that one is in front of the others when hiking. We notice that more people behind us get leech bites, probably because of their searching-curling-springing behavior. However, that’s not a guarantee, especially when there are so many people going up and down a mountain trail, for example, during Holy Week. During peak season of visitors, leeches also abound even in the Mudspring Area.
Some people mentioned using urine to remove leeches from their biting points, but I don’t, I won’t recommend it. Unlike jellyfish stings which involve toxins, leech bites involve only anticoagulants. The warm and salty nature of urine possibly helps remove leeches, but leech bites, being open wounds, would be more prone to secondary infection from bacteria or other microorganisms in the urine. The better way is to always have salt packets or concentrated salt solution sprays ready (in a small atomizer or handy bottle). More diluted salt solutions are recommended for removing them from the eyes. Again, do not use alcohol for bites in the eyes. Hold or squeeze the leech at its front or anterior suckers (“head” part), and swipe or pull/push sideways to remove or dislodge it. Leeches attract attention and annoy us when we go out and commune with nature or conduct fieldwork for scientific research. After we leave the forest, only wounds from leech bites are left and they heal eventually. In the Philippines, as in most other places, there is no sustained interest to study leeches, their taxonomy, diversity, ecology, and potential uses. It remains that most of what we know about leeches had been products of research on the European medicinal leech, Hirudo medicinalis. It would help us appreciate them better to know that H. medicinalis is just one of several “medicinal leeches.” There are other species of Hirudo that are sometimes also used as medicinal leeches. They include H. orientalis, H. troctina, and H. verbena. The Asian medical leech belongs to another genus and is known to science as Hirudinaria manillensis, while the North American medical leech is Macrobdella decora. These medicinal or medical leeches are largely aquatic (freshwater). The common land leech that we have in Mount Makiling belongs to Haemadipsa. I just hope somebody or some people pick them up for a more serious study. They are relatively small. They can be brightly colored. And they can also be beautiful in their own way.
Well, diversity is beautiful.