Horsehair Worms

Test tube wormThe horsehair worm is a parasite that lives in water, and its larvae infect insects.   Every year or two,  a panicky client finds one of these in a toilet bowl, water dish, or a bit of pet vomit.  They do not infest the pets, but the crickets or beetles may be eaten by a pet,  and the worm puked up.   If the insect enters the water, the mature parasite will exit to begin its life cycle anew.

There is really no harm in them (unless you’re the unlucky insect).  I’ve kept this specimen in a test tube for years .  If you stretched it out, it would be eight inches long.

 This fall, we have been plagued by an unusually large influx of crickets as the weather cooled off.   They apparently come inside to get warm.  There  have always been a few in the fall, but
hardly enough to notice.  This year they have really been annoying.  One of the elementary schools called in an exterminator after finding hundreds of them in a utility room. I have stepped on dozens of them in my clinic in the last month.

Cricket PinataI thought they had run their course, but I stepped on yet another cricket yesterday and out popped a horsehair worm, sort of a cricket pinata.

I thought the picture might be interesting to you.  When still alive, they tend to “tie themselves in knots”, hence their other nickname, the Gordian worm.

Here are  a couple of links with more information, if you’re interested.

http://www.marietta.edu/~biol/field_station/field_notes/horsehair.htm

http://www.ca.uky.edu/entomology/entfacts/ef613.asp

18 thoughts on “Horsehair Worms

  1. Angela McCoanughy says:

    ***WARNING***
    This is not factual info for anyone reading. Horsehair worms can indeed infect humans and animals and, are incredibly difficult,near impossible to irradicate. Do not take this data as fact.

    • Sydney Johnson says:

      I don’t know where you got your info, but they are actually correct. They cannot infect humans or pets. They can definitely be ingested, as there have been cases of them being found in human waste or vomit, but they cannot actually parasitize any person or pet. They are actually considered ineffective as a biological control agent (an organism used for pest control) because it can only infect such a small percent of hosts. Maybe you’re thinking of another parasite. Here are some articles if anyone would like to read further, and there are many more available in addition to these.

      https://www.kqed.org/science/1937775/these-hairworms-eat-a-cricket-alive-and-control-its-mind

      http://ipm.ucanr.edu/PMG/PESTNOTES/pn7471.html#:~:text=Horsehair%20worms%20are%20harmless%20to,tract%2C%20but%20infection%20never%20occurs.

      • Ashley says:

        Animals, worms included, evolve; I guarantee you my dog and I are infected with horse hair worms, per diagnosis and testing.

      • Doc says:

        Hello, Di,
        It is certainly possible to have filarial worms in the skin. It is common in tropical countries when people swim in streams and lakes. My daughter had to deal with this when she was in the Peace Corps in Zambia. Horsehair worms do NOT parasitize mammals. They parasitize insects.

        • Judkins Dena says:

          I 100% agree with you! I’ve spent 3 month trying to get someone to listen to me. Those damn horsehair worms were able to infest my 3 dogs and myself!
          I took a one time dose of 4 tabs of the ivermectin and my inside dogs were diagnosed with what he thought was roundworms and the vet stated other parasites!?!
          My dogs are 5, 6 and 7 years old they only go in our fenced in back yard. I take them regularly to the vet for all annual exams and if anything else occurs. I keep them bathed, shoot I had just paid $587 for the aussies to get their teeth cleaned. I have a 7 yr old morkie that has just gone blind during this infestation. I have videos and pics that demonstrate the whole lifecycle of these nasty parasites! Let’s not forget what they actually do to your hair. These damn things have wreck havoc upon my dogs and I.
          It’s a shame that science has become so closed minded, EVERYTHING EVOLVES!
          Even the CDC are investigating the cases of the parasite “horsehair worms”
          Infecting humans… multiple reports. So to those that say that they don’t infect those with a vertebrae, well I can prove you wrong any day of the week! Screw the ER because if it’s not in a textbook then it doesn’t exist for them. I’m a registered nurse for 30 years I beg to differ!

          • Lois says:

            Oh I agree I have had the exact same thing and nobody even infectious disease wants to know about it they just send you home

        • Ashley says:

          I would suggest updating your research. I too have horse hair worms and so does my dog. Thousands of people are struggling with the same issues and continue to get denied care because of comments like yours. Horse hair worms can and are infecting humans and animals. We are living proof. If someone thinks they have them with their dog, please give them respectful treatment.

          Members of the Nematomorpha are known as horsehair worms or gordian worms (Fig. 10.3L) and are parasites. Some species are parasitic on humans, but invertebrates and other vertebrates serve as hosts.
          https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/nematomorpha

    • Ashley says:

      Agreed! My dog and I are infested and shedding horse hair worms; have been for months. We are both struggling to become will again.

    • Lois says:

      I would love to know more about what you know as I have been dealing with them for two months I had them in my hair and on my body and my dogs have them as well they bite and get under my skin any information would be very

  2. LeAndrea Mae says:

    I have had horsehair nematomorpha burrowing in my skin coming out of chronic skin lesions for 22 months, with my iCloud overflowing with pix along the way. I am a medical transcriptionist of 17 years and have done more research on my symptoms than about a dozen docs in half dozens specialties, combined. I’m feeling smarter than the average doctor but dumber than the average transcriptionist because it took me almost 2 years to dig far enough into google and YouTube to just Wednesday a documented self diagnosis of horsehair nematomorpha with severe home infestation. They’re coming out of face lesions, watched a glob of face tissue I dug out with a metal pimple popper tool, then spent the next hour videoing it hatch twin nematodes. I have a horsehair worm in a baggie in saline now to bring first thing Monday morning to my first appointment with a wound care clinic, which I’ve been asking to see for about 18 months for non healing wounds, which I’ve typed in med records for 17 yrs. Denied my request ID due to worm specimen from my back wound had negative path results for parasites and fungus…,because nematodes need to be tested for nematodes specifically! Duh! I’m now sitting Friday night surrounded by what I always thought was kitty fuzzies from my TWO black cats, thinkn the white feathery looking feathers were shedding from my goose down bedding set! I don’t even trust doctors so I’m home with worms in my face and ears and eyes and nose and mouth when I eat, freak’n w the worms thst are about to make me lose my cute mobile home I just put on a big truck to become the wide load down the highway relocating to the park my oldest daughter and 3 grandsons live in, so my grandsons can walk over to raid my fridge anytime. I moved also to get away from a neighbor charged with stalking me. He pled guilty October of 2021 but at his sentencing in March I wasn’t able to give my impact statement because he then said he don’t want to be guilty, waiting on jury trial date. I’m on disability income but work part time to supplement, as a medical y transcriptionist working from home, with plans to evacuate asap somehow with my back account overdrafted. Anyone got any advice plz, thank u kindly

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