This article by Jerry Cates and Michelle Sparks, first published on 17 November 2012, was last revised on 29 November 2012. © Bugsinthenews Vol. 13:11(03).
On 12 November 2012 Michelle Sparks wrote:
I’m not sure if you’re still collecting encounter reports on the puss caterpillar, but if you are, I thought I should add my experience to your report.
My husband and I live in Phoenix, but we visited San Antonio this past weekend, and had dinner at a restaurant along the River Walk. It was a nice restaurant with an open patio. I had a sweater with me, as temperatures were brisk. I didn’t notice that the sweater had fallen to the floor while I ate and talked with friends. Afterward, on leaving the restaurant, I put the sweater over my arms and we drove to another place. Soon afterward I noticed that my right forearm, near my elbow, began to burn and become painful. I thought maybe I’d brushed up against a bush or something. As soon as it was convenient, I washed the burning area on my arm well with soap and water and took a Benadryl tablet, but the burning continued to progress. The pain spread up my arm, over my shoulder, into my arm pit, and from there into my chest.
Nothing really showed on my arm, really. Just some tiny “goosebumps” about the size of a tennis ball. Nobody I showed the sting site to recognized it as a sting, but because the pain kept getting stronger I put ice on the sting site, which helped some with the burning. The pain was similar to a broken bone, and I had significant swelling through my hand. I also had so little strength in my hand that I couldn’t hold a fork or knife.
As the pain continued to worsen, I began to wonder if I was suffering a heart attack. Our friends drove me to the nearest Emergency Room where the doctor immediately recognized that I had been stung by a tree asp. I had not seen a caterpillar at the restaurant, and though we closely examined the sweater we did not find a caterpillar on it either. I am planning to throw away the sweater, assuming that it likely has barbs from the now-gone caterpillar still in it. While at the emergency room I was treated with the iv pain medicine diladid, and the steroid solumedral. I was also given an anti-nausea medication, a steroid prescription, a chest X-ray and a complete blood-work.
The next morning, in our hotel, I awoke with a horrible headache and a case of nausea with vomiting and ongoing pain. It took another 12 hours to feel better. Today, more than 48 hrs later, my hand is still swollen, I still have a headache, and my arm is still hot.
We walked along the San Antonio River Walk again yesterday and saw 4 fuzzy caterpillars along our way. I photographed 2, which I’ve included.
Again, I never saw the one that stung me.
The ER physician pointed us to your website and I read it through. I had no idea caterpillars stung!
I used the tape trick last night- 1.5 days after the sting, hoping it would help.
Thank you for all your research on this nasty bug.
Michelle Sparks, Phoenix, Arizona”
Michelle’s experience is essentially identical to that of the hundreds of puss caterpillar sting victims I’ve corresponded with over the past decade and more. The photos she took of two caterpillars found on the San Antonio River Walk two days after she was stung are of urticating caterpillars, and at least one of them (fig. 100) is very likely a puss caterpillar in the genus Megalopyge. I am using her encounter report as an opportunity to update the information previously posted on bugsinthenews regarding this noxious insect. Hopefully, much of the necessary revisions will be completed by Sunday, 18 November.
(1) It is disappointing to note that the emergency room physician who correctly diagnosed Michelle’s sting, and then administered and prescribed medications such as dilaudid and steroids, failed to take steps known to be capable of removing the caterpillar’s toxic spines from the sting site. The most common method for removing the caterpillar’s spines is to gently, but repeatedly, apply and remove a strip of adhesive tape over the sting site. All of the exposed microscopic, toxin-filled spines can be withdrawn from the sting victim’s skin in the process, immediately granting pain relief in the process. Read my comments about poultices, that some have used to deal with the residual pain after taping the site, in the comments section below this article.
(2) Michelle stated she was going to throw the sweater away, but I recommended against that. A good dry cleaning or laundering should be enough to remove whatever spines might remain in the sweater material (most likely none remain at all).
(3) Michelle indicated, in a later e-mail, that she and her husband were visiting San Antonio to see if they might relocate to that city from Phoenix, but now she was having second thoughts. I pointed out to her that puss caterpillars are found all over the United States, including Phoenix, and that most residents of San Antonio have never seen one of these critters. So her second thoughts on relocating to that beautiful Texas city are misplaced. Within hours of posting this article a report was received from Orlando, Florida (home of Disney World) about a puss caterpillar sting that took place there that day. I regularly receive reports of puss caterpillar stings from some of the most popular and beautiful cities in North America. The painful experience those stings produce (not to mention the emergency room and hospitalization expense, which can run into tens of $thousands if the E.R. physician does not recognize the cause of the pain before ordering a battery of unnecessary tests and scans) makes for bad memories that detract from a locale’s allure. Still, such stings can happen almost anywhere in the U.S., Mexico, and Central and South America.
(4) Because puss caterpillar stings are accompanied by excruciating pain, they masquerade as a serious medical crisis (but see note 5, below). This leads the victim to seek professional medical intervention, which often results in staggering medical bills and hours of uncertainty while awaiting the results of hastily ordered tests, scans, and laboratory analyses. Individuals familiar with puss caterpillar stings realize the pain is self-limiting (though it can last for hours, or even days, if nothing is done to remove the microscopic spines from the skin), and that much can be done to reduce or bring the pain to a stop, by the sting victim and others, through taping and the use of inexpensive and easily prepared poultices (see more on these in my article on Puss Caterpillar Stings–Home Remedy First Aid Measures). Thankfully, puss caterpillar encounters are relatively rare, even in locales where the puss caterpillar is endemic. The downside of this is that few individuals know enough to calm the victim’s fears and point them toward the practical remedies at their immediate disposal.
(5) For some, particularly those afflicted with serious medical conditions and susceptible to allergic reactions and chemical intolerances, puss caterpillar stings — as with envenomations from other arthropods — CAN INDEED represent A SERIOUS MEDICAL CRISIS. Never attempt a home remedy for an envenomation event of any kind for such individuals. Instead, seek immediate professional medical help at the nearest emergency room, hospital, or medical center.
Links: (1) Puss Caterpillar General Information. (2) The Puss Caterpillar’s Stinging Apparatus. (3) Puss Caterpillar Extermination. (4) The Puss Caterpillar’s Natural Predators. (5). Puss Caterpillar Stings–Medical Interventions. (6) Puss Caterpillar Stings–Home Remedy First Aid Measures.
- Kingdom Animalia (ahn-uh-MAYHL-yuh) — first described in 1758 by the Swedish taxonomist Carolus Linnaeus (1707 – 1778), using the Latin word animal = “a living being,” from the Latin word anima = “vital breath”, to refer to multicellular, eukaryotic organisms whose body plans become fixed during development, some of which undergo additional processes of metamorphosis later in their lives; most of which are motile, and thus exhibit spontaneous and independent movements; and all of whom are heterotrophs that feed by ingesting other organisms or their products;
- Phylum Arthropoda (ahr-THROPP-uh-duh) — first described in 1829 by the French zoologist Pierre André Latreille [November 20, 1762 – February 6, 1833], using the two Greek roots αρθρον (AR-thrawn) = jointed + ποδ (pawd) = foot, in an obvious reference to animals with jointed feet, but in the more narrow context of the invertebrates, which have segmented bodies as well as jointed appendages;
- Class Insecta (ehn-SEK-tuh) — first described in 1758 by the Swedish taxonomist Carolus Linnaeus (1707 – 1778), using the Latin word insectum, a calque of the Greek word ἔντομον ( EN-toh-mawn) = “(that which is) cut into sections”; comprised of arthropods with chitinous external (exo-) skeletons, a three part body composed of a distinct head, thorax, and abdomen, the midmost part having three pairs of jointed legs, and the foremost part having a pair of compound eyes and antennae;
- Subclass Pterygota (tare-ee-GOH-tah) — first described in 1888 by Lang, using the Greek roots πτερυξ (TARE-oos) = wing, to refer to insects with wings, or that had wings but in the process of evolution have since lost them;
- Infraclass Neoptera (nee-OPP-tur-uh) — first described in 1890 by the Dutch entomologist Frederick Maurits van der Wulp (1818-1899) using the Greek roots νεος (NEE-ose) = youthful, new + πτερυ (TARE-ohn) = wing, to refer to winged insects that are capable of folding their wings over their abdomens, in contrast to more primitive winged insects that are unable to flex their wings in this manner (e.g., the dragonflies, in the infraclass Paleoptera);
- Superorder Endopterygota (ehn-doh-tare-ee-GOH-tah) — first described by the English physician and entomologist David Sharp (1840-1922) using the Greek root ενδον (ENN-dohn) = within + the established expression pterygota (see above) to refer to insects within the latter subclass that undergo complete metamorphosis, i.e., larval, pupal, and adult stages;
- Order Lepidoptera (lep-uh-DOPP-tur-uh) — first formally described in 1758 (though he coined the expression in 1735, informally) by the Swedish taxonomist Carolus Linnaeus (1707 – 1778), using the Greek roots λεπιδωτος (lepp-eh-DOH-tose) = scaly + πτερυ (TARE-ohn) = wing, to refer to insects with scales covering their wings, i.e., the moths and butterflies;
- Family Megalopygidae (megg-uh-low-PIDGE-uh-dee) — from the Greek root μεγας (MEG-as) = great, vast, large + the Greek root πυγη (PIDGE-ee) = rump, tail + the Greek patronymic suffix -ιδες (eye-DEES) commonly used in zoological taxonomy to indicate a family name, in reference to a family of moths typically having an exaggerated tail, honoring the fact that these caterpillars often–but not always–trail a conspicuous tail of hairs; this family is presently represented by 23 recognized genera that are found in North America and in the New World Tropics; in North America as many as 44 species have been described, some of which may be synonyms, but all of which are known, while in the larval (caterpillar) stage, to produce extremely painful stings in humans who come into contact with them;
- Avilán, Luisana, et al. 2010. Description of envenomation by the “gusano-pollo” caterpillar (Megalopyge opercularis) in Venezuela. Invest Clin 51(1): 127 – 132.
- Bennett, Gary W. 2010. Truman’s Scientific Guide to Pest Management Operations 7th Edition. Purdue University.
- Borror, Donald J., and Richard E. White. 1970. A Field Guide to Insects: America North of Mexico. Houghton Mifflin Company
- Bradley, Fern Marshall, et al. 2010. The Organic Gardener’s Handbook of Natural Pest and Disease Control: A Complete Guide to Maintaining a Healthy Garden and Yard the Earth-Friendly Way (Rodale Organic Gardening Books). Rodale Inc.
- Eagleman, David M. 2007. Envenomation by the asp caterpillar (Megalopyge opercularis). Clinical Toxicology (2007) iFirst, 1–5.
- Epstein, Marc E. 1995. Evolution of locomotion in slug caterpillars (Lepidoptera: Zygaenoidea: Limacodid group). J. Res. Lepidoptera 34:1-13.
- Foot, Nathan Chandler. 1922. Pathology of the Dermatitis caused by Megalopyge opercularis, a Texan caterpillar. JEM 35(5): 1 May 1922.
- Khalaf, Kamel T. 1974. Nonasceptic Wheat Germ Diet for Megalopyge opercularis (Lepidoptera: Megalopygidae). The Florida Entomologist 57(4):377-381.
- Klotz, John H. et al. 2009. Animal Bites and Stings with Anaphylactic Potential. J. Emerg. Med. 36(2):148-156.
- Lifton, Bernice. 2005. Bug Busters: Poison-Free Pest Controls for Your House and Garden. Square One Publishers.
- Mallis, Arnold, Stoy Hedges (Ed.) et al. 2011. The Mallis Handbook of Pest Control, 10th Edition. The Mallis Handbook Company.
- Neck, Raymond W. 1976. Lepidopteran Foodplant Records from Texas. J. Res. Lepidoptera 15(2):75-82.
- Steen. Christopher J. et al. Arthropods in dermatology. J. Am. Dermatol. 50(6):819-842.
- Stewart, Amy. 2011. Wicked Bugs: The Louse That Conquered Napoleon’s Army & Other Diabolical Insects. Algonquin Books of Chapel Hill.
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