Megalopyge Opercularis Research Articles

Severely Painful and Pruritic Forearm Rash: A Case of Caterpillar Envenomation in South Florida.

The asp caterpillar (Megalopyge opercularis) is endemic to the southeastern United States, with most sightings in Florida, Texas, and Louisiana. A few hundred caterpillar envenomations are reported annually with most cases occurring in July-November. Asp caterpillars have hollow spines along their backs that contain venom. Contact with these spines is what produces the characteristic "sting" resulting in contact dermatitis and a localized hypersensitivity reaction collectively referred to as lepidopterism. Symptoms of lepidopterism may include severe burning pain, pruritis, edema, nausea, vomiting, abdominal pain, and headache. Symptoms are often self limited, and treatment should focus on expedited removal of implanted spines and aggressive symptom management. We present the case of a patient presenting to the emergency department (ED) with acute-onset severe left forearm pain with associated pruritic rash incurred while working in a retail store. Initial therapeutic management included administration of analgesics, antihistamines, and steroids. After obtaining a comprehensive history and consulting with the Poison Control Center, we suspected an asp caterpillar envenomation. Following extraction of the caterpillar spines with silk tape, the patient's symptoms improved. After a period of observation in the ED, the patient was discharged home without any known sequelae. Although asp caterpillars typically inhabit trees and foliage, human exposure to the caterpillar may occur in developed environments. Effective history-taking, prompt communication with toxicologic experts, and complete removal of intact spines are essential for early identification and effective clinical management of asp caterpillar envenomation.

Geographical and temporal distribution of Megalopygidae in the United States and Puerto Rico

BackgroundThe venom of Megalopygidae caterpillars causes inflammation and pain. Understanding geographic and temporal variation in exposure will help physicians and the public understand when and where the species in this family may be encountered. MethodsPhotographs uploaded by community scientists to the iNaturalist database were reviewed and identified. GIS data points were used to model distribution of species based on geographic variables at the location of photographs for each group. Data on temporal abundance was also noted. ResultsMaps were created predicting the geographic range for 11 species of Megalopygidae. Peak larval abundance for the most abundant species, Megalopyge opercularis, was determined as September in the southeastern United States and October in south-central US. ConclusionGeographic and temporal distributions, based on community science observations, allow for more accurate predictions on the likelihood of encountering venomous Megalopygidae caterpillars.

Horizontal gene transfer underlies the painful stings of asp caterpillars (Lepidoptera: Megalopygidae)

Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), known as asp or puss caterpillars, produce defensive venoms that cause severe pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata. We show that megalopygid venom is produced in secretory cells that lie beneath the cuticle and are connected to the venom spines by canals. Megalopygid venoms consist of large aerolysin-like pore-forming toxins, which we have named megalysins, and a small number of peptides. The venom system differs markedly from those of previously studied venomous zygaenoids of the family Limacodidae, suggestive of an independent origin. Megalopygid venom potently activates mammalian sensory neurons via membrane permeabilization and induces sustained spontaneous pain behavior and paw swelling in mice. These bioactivities are ablated by treatment with heat, organic solvents, or proteases, indicating that they are mediated by larger proteins such as the megalysins. We show that the megalysins were recruited as venom toxins in the Megalopygidae following horizontal transfer of genes from bacteria to the ancestors of ditrysian Lepidoptera. Megalopygids have recruited aerolysin-like proteins as venom toxins convergently with centipedes, cnidarians, and fish. This study highlights the role of horizontal gene transfer in venom evolution.

Larvas urticantes (Lepidoptera) asociadas con cultivos hortícolas en Cerro Punta, Chiriquí, Panamá

The objective of this study was to identify Lepidoptera stinging larvae found in plots with horticultural crops in Cerro Punta, Chiriquí, Panama and to confirm the possible symptoms caused by erucism and lepidopterism. About 16 random samplings were carried out during 14 and a half months, in plots with crops, surrounding vegetation and infrastructure. Photographs were taken and samples were collected for processing in the laboratory. Specialized literature was consulted for identification. A survey of 33 people affected by erucism or lepidopterism was carried out. According to the results, the larvae found on the crops corresponded to Leucanella hosmera (Schaus, 1941) (Saturniidae), Halysidota tessellaris (Smith, 1797) (Erebidae), Acharia stimulea (Clemens, 1860) (Limacodidae) and an adult specimen of Megalopyge opercularis (Smith, 1797) (Megalopygidae) was also found on a wall. In wild vegetation, L. hosmera and possibly Automeris pallidior Draudt, 1929 (Saturniidae) larvae were found feeding on Faramea occidentalis (L.) A. Rich (Rubiaceae). The survey reflected burning, pain and inflammation as frequent symptoms due to erucism or lepidopterism in 93.9%, requiring medical attention in 18.18% of cases. In conclusion, five species of stinging larvae associated with horticultural crops were identified in Cerro Punta, which represent a potential health risk.

Lepidopterism caused by the puss caterpillar.

Lepidopterism is a term inclusive of cutaneous and systemic reactions resulting from moths, butterflies, and larva. The puss caterpillar is the larval form of the southern flannel moth, Megalopyge opercularis. A case presentation is reviewed and treatment options presented for contact with puss caterpillars and other stinging caterpillars encountered in the primary care setting. Contact with the puss caterpillar causes a characteristic rash and can produce extreme symptoms of pain for its victims. Accurate and early diagnosis can expediate treatment to alleviate symptoms and decrease morbidity in those affected and aid in differential diagnosis of various stinging caterpillars.

In vitro antitumor, pro-inflammatory, and pro-coagulant activities of Megalopyge opercularis J.E. Smith hemolymph and spine venom

Contact with stinging spines venom from several Lepidoptera larvae may result in skin lesions. In Mexico, envenomation outbreaks caused by Megalopyge opercularis were reported between 2015 and 2016. The aim of this study was to identify the venomous caterpillars in Nuevo Leon, Mexico and evaluate several biological activities of their hemolymph (HEV) and spine setae (SSV) venoms. M. opercularis was identified by cytochrome oxidase subunit (COI) designed primers. HEV and SSV extracts cytotoxic activity was assessed on the L5178Y-R lymphoma cell line. For apoptotic cells number and apoptosis, cells were stained with acridine orange/ethidium bromide and validated by DNA fragmentation. Human peripheral blood mononuclear cells (hPBMC) cytokine response to the extracts was measured by the cytometric bead array assay. Extracts effect on pro-coagulation activity on human plasma was also evaluated. HEV and SSV extracts significantly inhibited (p < 0.01) up to 63% L5178Y-R tumor cell growth at 125–500 µg/mL, as compared with 43% of Vincristine. About 79% extracts-treated tumor cells death was caused by apoptosis. Extracts stimulated (p < 0.01) up to 60% proliferation of resident murine lymphocytes, upregulated IL-1β, IL-6, IL-8, and TNF-α production by hPBMC, and showed potent pro-coagulant effects. The pharmacological relevance of these venoms is discussed.

What's eating you? Megalopyge opercularis.

Caterpillars-the larval form of butterflies and moths-belong to the order Lepidoptera. Some identified caterpillars from this order have developed venomous defense mechanisms such as irritating hairs and spines to protect themselves from predators. Direct contact to allergenic caterpillars' hairs can cause human disease. Cutaneous lesions following caterpillar envenomation can range from mild localized inflammatory signs and pain to a worsening appearance of vesicles, bullae, erosions, petechiae, necrosis, and ulceration. This review addresses the varied general manifestations caused by venomous lepidopteran exposure with special focus on the adverse cutaneous manifestations and therapeutic options of Megalopyge opercularis, the caterpillar of the flannel moth.

Human-mediated disturbance in multitrophic interactions results in outbreak levels of North America's most venomous caterpillar.

Anthropogenic environmental change is predicted to disrupt multitrophic interactions, which may have drastic consequences for population-level processes. Here, we investigate how a large-scale human-mediated disturbance affects the abundance of North America's most venomous caterpillar species, Megalopyge opercularis. Specifically, we used a natural experiment where netting was deployed to cover the entire canopies of a subset of mature southern live oak trees (Quercus virginiana) to exclude urban pest birds (grackles and pigeons), throughout an 8.1 km2 area encompassing a medical centre in Houston, Texas. We used this experimental exclusion to test the following hypothesis: release from avian predators increases caterpillar abundance to outbreak levels, which increases the risk to human health. Results from a multi-year survey show that caterpillar abundance increased, on average, more than 7300% on netted versus non-netted trees. Thus, increases in caterpillar abundance due to anthropogenic enemy release increase human exposure to this venomous pest, and should be considered a health threat in the area. This study emphasizes the unforeseen consequences of ecological disturbance for species interactions and highlights the importance of considering ecology in urban planning.

Megalopyge opercularis Caterpillar Stings Reported to Texas Poison Centers

The Megalopyge opercularis caterpillar is covered with spines that break off and release venom on contact, resulting in severe pain, erythema, rash, and other adverse effects. In Texas, these caterpillars are abundant and of potential health threat. This study describes M opercularis caterpillar stings reported to Texas poison centers. Cases were M opercularis caterpillar stings reported to Texas poison centers during 2000-2016. The distribution of stings was determined related to exposure circumstances and management. There were 3484 M opercularis caterpillar stings reported during 2000-2016. The annual number of stings did not consistently change over the 17-year time period. The monthly number of stings was highest in July (12%) and October to November (59%). The patients were female in 53% of cases and aged 20 years or more in 56%. The sting occurred at the patient's own residence in 91% of cases. The patients were managed outside of a healthcare facility in 89% of cases; 93% of the patients were known or expected to have no or at most minor clinical effects. Dermal clinical effects were reported in 90% of cases, the most common being irritation/pain (84%), puncture/wound (45%), erythema/flushed (29%), and edema (15%). M opercularis caterpillar stings reported to Texas poison centers were more frequently reported in July and October to November. Most of the patients were adults. The majority of patients were managed outside of healthcare facilities and did not have serious outcomes. Most of the adverse clinical effects were dermal in nature.

Puss Caterpillar (Larva), Southern Flannel Moth (Adult), Megalopyge opercularis (J. E. Smith 1797) (Insecta: Lepidoptera: Zygaenoidea: Megalopygidae)

The southern flannel moth is an attractive small moth that is best-known because of its larva, the puss caterpillar, which is one of the most venomous caterpillars in the United States. This 12-page fact sheet was written by Donald W. Hall and published by the UF Department of Entomology and Nematology, January 2013.&#x0D; http://edis.ifas.ufl.edu/in976

Envenomation by the asp caterpillar (Megalopyge opercularis)

Background. The Asp Caterpillar, Megalopyge opercularis, is endemic to the southern United States and causes hundreds of human envenomations annually. Envenomation from the spines of the caterpillar causes severe pain, burning, swelling, nausea, abdominal distress, and headache. Despite the high prevalence of envenomations, little is known about the caterpillars, their geographical distribution, and the symptoms they engender. Methods. We collected and analyzed 188 case reports of asp caterpillar envenomations over a three-year period. Results. The geographical distribution of the caterpillars is confined to the southeast United States, largely in Texas, Louisiana, and Florida. Symptoms of envenomation vary, but typically include burning pain, swelling, nausea, and itching. The peak months of envenomation are July through November, with few cases reported at other times of year. Discussion. This study sheds light on the caterpillars' distribution and the range of symptoms caused in order to aid in diagnosing puss moth caterpillar envenomation.

Visual Diagnosis: A Painful Rash

Puss caterpillar (Megalopyge opercularis) envenomation. The puss caterpillar, also known as an “asp” or “woolly slug,” is the larval stage of a flannel moth1 (Figure 2). It is regarded as the most poisonous caterpillar found in the United States and is found predominantly in the southern states, although its habitat ranges west to Texas and north to Maryland and Missouri. Symptoms of envenomation commonly include local pain, itching, rash, and lymphadenopathy but may progress to systemic symptoms such as nausea, vomiting, and fever.

The venomous hair structure, venom and life cycle of Lagoa crispata, a puss caterpillar of Oklahoma

The presence of a unique population of Lagoa crispata, puss caterpillar, in western Oklahoma is reported. A detailed microscopic examination shows the structure of the L. crispata spines resemble the type 4 spines described by [Kawamoto, F., Kumada, N., 1984. Biology and venoms of lepidoptera. In: Tu, A.T. (Ed.), Handbook of Natural Toxins, Insect Poisons, Allergens and other invertebrate venoms, vol. 2, pp. 291–332 (ch. 9)]. The major food source of L. crispata are the leaves of oak (shin oak). The high tannin content of this food source results in spine extracts high in oak tannins. These extracts have activity but enzyme and toxin activity is lost with time. The gel filtration protein fractions are colored from brown to yellow and are inactive as enzymes or toxins. No hyaluronidase, protease or phosphohydrolase activity is detected in these protein fractions. The life cycle shows these caterpillars have 6 instars. Characterizations and annual emerging times of each instar are included.

A Retrospective Analysis of 96 “Asp” (Megalopyge opercularis) Envenomations in Central Texas During 1996

The most frequently reported caterpillar envenomation in Central Texas is by the puss caterpillar or "asp," Megalopyge opercularis. This caterpillar is described by patients and physicians as inflicting intense radiating pain. The intensity of symptoms may be underestimated leading to undertreatment. Adequate treatment protocols have been lacking and those in use are not very successful. We present a retrospective study of patients who were stung and contacted the Central Texas Poison Center. All human exposures to asp stings reported to the Central Texas Poison Center during 1996 were included. Inclusion criteria consisted of all cases documented as an asp envenomation by the specialists in poison information. Characterization of symptoms and treatment used were evaluated. There were 96 exposures to asps reported. Ninety-five of the patients experienced local pain with 26 of these reporting intense radiating pain. Forty developed erythema, 27 described edema, and 9 complained of welts/hives. Other symptoms reported included white spots (4), pruritus (3), red streak (2), numbness (2), and individual accounts of chest pain, rash, ecchymosis, tingling, blister, and muscle spasm. There was no treatment modality that promptly relieved pain. Although asp envenomations appear to be very common, clinical cases have rarely been documented. This may be due to physicians not recognizing the etiological agent. Pain may be very intense and standard pain management appears to be unsuccessful. This study suggests that further examination of treatment modalities may be beneficial in addressing the morbidity of Megalopyge opercularis envenomations.

Sting of the Puss Caterpillar: An Unusual Cause of Acute Abdominal Pain

We report the case of a 41-year-old man with abdominal pain after envenomization by a puss caterpillar. The patient's medical history and physical examination revealed classic symptoms, leading to the correct diagnosis and appropriate therapy with intravenous calcium gluconate. Although severe, local reactions to puss caterpillar envenomization have been previously described, to our knowledge this is the first report of a patient with severe, acute abdominal pain caused by a puss caterpillar's sting.

Envenomation by the puss caterpillar ( Megalopyge Opercularis)

We discuss the case of a 52-year-old woman who developed urticarial lesions after the acute envenomation of a puss caterpillar (Megalopyge opercularis). The puss caterpillar, one of more than 50 species of caterpillars that can cause envenomation in the United States, is considered to be one of the most serious. Its clinical presentation and current recommended treatments are reviewed.

The histology and cytology of the urticating structures of the puss caterpillar, Lagoa crispata (Packard) (Lepidoptera: Megalopygidae): Jay Lamdin 5, D. E. Howell 2, John Venable 4, Ray Eikenbary 2, Kathy Kocan 3 and George Odell1 (Departments of 1Biochemistry, 2Entomology and 3Pathology, School of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078; 4School of Veterinary Medicine, Colorado State University, Colorado

The histology and cytology of the urticating structures of the puss caterpillar, Lagoa crispata (Packard) (Lepidoptera: Megalopygidae): Jay Lamdin 5, D. E. Howell 2, John Venable 4, Ray Eikenbary 2, Kathy Kocan 3 and George Odell1 (Departments of 1Biochemistry, 2Entomology and 3Pathology, School of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078; 4School of Veterinary Medicine, Colorado State University, Colorado

Puss Caterpillar Sting in Arkansas

Puss Caterpillar Sting in Arkansas

Nonaseptic Wheat Germ Diet for Megalopyge opercularis (Lepidoptera: Megalopygidae)

A nonaseptic, wheat germ, agar-based diet has been developed for rearing the puss caterpillar, Megalopyge opercularis Abbot and Smith.

Observations on the effect of hurricane “Carla” on insect activity

Observations in the laboratory under conditions of controlled temperature and relative humidity on the effects of low barometric pressures on insect activity resulting fron hurricane “Carla”, one of the largest and most destructive hurricanes to affect the middle coast of Texas, revealed that stable flies (STOMOXYS CALCITRANS (L.)), house flies (MUSCA DOMESTICA L.), and Mexican fruit flies (ANASTREPHA LUDENS (Loew)), cockroaches (BLATELLA GERMANICA (L.)), PERIPLANETA AMERICANA (L.), and BLABERUS GIGANTEUS (L.) and mosquitoes (AEDES AEGYPTI (L.), exhibited nervous activity concomitant with the reduction in barometric pressure. Field studies throughout the critical storm period also indicated unusual arthropod activity. Following the hurricane, certain insect species emerged in abnormally large numbers, particularly fall armyworms (LAPHYGMA FRUGIPERDA (J.E. Smith)), “asps” (MEGALOPYGE OPERCULARIS (J. E. Smith)), and southern green stink bugs (NEZARA VIRIDULA (L.)).