Prospective study of definite caterpillar exposures

Venom composition and bioactive RF-amide peptide toxins of the saddleback caterpillar, Acharia stimulea (Lepidoptera: Limacodidae)

Limacodidae is a family of lepidopteran insects comprising >1500 species. More than half of these species produce pain-inducing defensive venoms in the larval stage, but little is known about their venom toxins. Recently, we characterised proteinaceous toxins from the Australian limacodid caterpillar Doratifera vulnerans, but it is unknown if the venom of this species is typical of other Limacodidae. Here, we use single animal transcriptomics and venom proteomics to investigate the venom of an iconic limacodid, the North American saddleback caterpillar Acharia stimulea. We identified 65 venom polypeptides, grouped into 31 different families. Neurohormones, knottins, and homologues of the immune signaller Diedel make up the majority of A.stimulea venom, indicating strong similarities to D. vulnerans venom, despite the large geographic separation of these caterpillars. One notable difference is the presence of RF-amide peptide toxins in A. stimulea venom. Synthetic versions of one of these RF-amide toxins potently activated the human neuropeptide FF1 receptor, displayed insecticidal activity when injected into Drosophila melanogaster, and moderately inhibited larval development of the parasitic nematode Haemonchus contortus. This study provides insights into the evolution and activity of venom toxins in Limacodidae, and provides a platform for future structure-function characterisation of A.stimulea peptide toxins.

Float like a Butterfly, Sting like One Too

Rash after contact with butterflies has not been previously reported in the medical literature to our knowledge. We describe potentially the first suspected case of a cutaneous reaction to the Compton tortoiseshell butterfly (Nymphalis vaualbum) in a young boy who developed urticaria after the modified hairs of the butterfly embedded within his finger. His urticaria improved through treatment with oral and topical steroids as well as systemic antihistamines. This case report expands the variety of insect species that may cause human disease and should raise awareness for this possible reaction.

Production, composition, and mode of action of the painful defensive venom produced by a limacodid caterpillar, Doratifera vulnerans

Venoms have evolved independently several times in Lepidoptera. Limacodidae is a family with worldwide distribution, many of which are venomous in the larval stage, but the composition and mode of action of their venom is unknown. Here, we use imaging technologies, transcriptomics, proteomics, and functional assays to provide a holistic picture of the venom system of a limacodid caterpillar, Doratifera vulnerans Contrary to dogma that defensive venoms are simple in composition, D. vulnerans produces a complex venom containing 151 proteinaceous toxins spanning 59 families, most of which are peptides <10 kDa. Three of the most abundant families of venom peptides (vulnericins) are 1) analogs of the adipokinetic hormone/corazonin-related neuropeptide, some of which are picomolar agonists of the endogenous insect receptor; 2) linear cationic peptides derived from cecropin, an insect innate immune peptide that kills bacteria and parasites by disrupting cell membranes; and 3) disulfide-rich knottins similar to those that dominate spider venoms. Using venom fractionation and a suite of synthetic venom peptides, we demonstrate that the cecropin-like peptides are responsible for the dominant pain effect observed in mammalian in vitro and in vivo nociception assays and therefore are likely to cause pain after natural envenomations by D. vulnerans Our data reveal convergent molecular evolution between limacodids, hymenopterans, and arachnids and demonstrate that lepidopteran venoms are an untapped source of novel bioactive peptides.

The Latoia consocia Caterpillar Induces Pain by Targeting Nociceptive Ion Channel TRPV1

Accidental contact with caterpillar bristles causes local symptoms such as severe pain, intense heat, edema, erythema, and pruritus. However, there is little functional evidence to indicate a potential mechanism. In this study, we analyzed the biological characteristics of the crude venom from the larval stage of Latoia consocia living in South-West China. Intraplantar injection of the venom into the hind paws of mice induced severe acute pain behaviors in wild type (WT) mice; the responses were much reduced in TRPV1-deficit (TRPV1 KO) mice. The TRPV1-specific inhibitor, capsazepine, significantly attenuated the pain behaviors. Furthermore, the crude venom evoked strong calcium signals in the dorsal root ganglion (DRG) neurons of WT mice but not those of TRPV1 KO mice. Among the pain-related ion channels we tested, the crude venom only activated the TRPV1 channel. To better understand the venom components, we analyzed the transcriptome of the L. consocia sebaceous gland region. Our study suggests that TRPV1 serves as a primary nociceptor in caterpillar-induced pain and forms the foundation for elucidating the pain-producing mechanism.

An unusual case of ingestion of a moth cocoon in a 14-month-old girl

We present a case report of a 14-month-old girl who ingested a moth cocoon, which resulted in dramatic symptoms of irritability, drooling, and anorexia. Direct laryngoscopy, bronchoscopy, and esophagoscopy under general anesthesia revealed copious, tenaciously adherent, barbed hairs embedded in her tongue and buccal mucosa. Removal of the hairs with irrigation, suction, and brushing was unsuccessful and was eventually abandoned. In the following 48 hours, the girl recovered uneventfully with supportive care. The hairs were subsequently identified as coming from the hickory tussock moth (Lepidoptera: Arctiidae: Lophocampa caryae), which is ubiquitously distributed throughout much of North America. This is the first detailed case report of ingestion of an L caryae cocoon.

Immune response profiles after caterpillar exposure: a case report

Rationale

The role of the immune response to caterpillar exposure is not well described. This case study is the first to report a patient who presented with an allergic reaction after exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864.

Methods

Blood was collected from an allergic asthmatic adult (m/42 y/o) at 2 hrs – 2 wks after contact urticaria with associated dyspnea after exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864. Distributions of blood lymphocytes (CD4⁺, CD8⁺, CD8⁺CD60⁺, CD19⁺, CD23⁺, CD16/56⁺, CD25, CD45RA⁺, CD45RO⁺), monocytes (CD1d⁺), levels of serum immunoglobulins (IgM, IgG, IgA, IgE), and cytokines (IFN-γ, IL-4, TNF-α) were studied (flow cytometry, nephelometry, UniCAP Total IgE Fluoroenzymeimmunoassay, cytokine ELISA, clinical toxicology).

Results

Numbers of CD4⁺ T cells, CD25⁺ cells, CD19⁺ B cells, and CD1d⁺ monocytes decreased (22, 27, 33, 20%, respectively) one week post reaction, CD45RA⁺ naïve T cells decreased at 36 hours (21%),while CD8⁺CD60⁺ T cells and CD23⁺ cells decreased 48 hrs (33, 74%, respectively) post reaction. In contrast, numbers of CD16/56⁺ NK precursor cells increased (60%) 12 hrs, then decreased (65%) 48 hrs post reaction; other lymphocyte subsets were unaffected. Serum IgM, IgG and IgA were within normal range; however, serum IgE demonstrated a bimodal elevation at 2 hrs (15%) and one week post reaction. Levels of IFN-γ, IL-4, and TNF-α were not detected in serum pre-exposure (<1.0–4.0 pg/mL). However, high levels of IFN-γ (187–319 pg/mL) and TNF-α (549–749 pg/mL) were detected in serum 24–36 hrs and 3.5–24 hrs post reaction, respectively. In contrast, levels of IL-4 were undetected (<1.0 pg/mL) in serum at all time points.

Conclusions

Exposure to the larvae of the sycamore tussock moth, Halysidota harrisii Walsh, 1864 may result in increased cytokine levels and blood CD16/56⁺ NK precursor cells.

A transatlantic caterpillar

BACKGROUND

Saddleback caterpillar sting has been very rarely reported in European countries. We report a French case of a stung toddler.

CASE

A 2-year-old girl was brought to the pediatric emergency department after being stung by a caterpillar in a furniture store. The emergency department physical examination revealed an inflammatory edema of the stung finger, normal vital signs, and no fever. Three hours after presentation, she was discharged with local ointment prescription. The caterpillar brought in by the parents was unusual compared to common French caterpillar species. The regional poison center was unable to identify it. With the help of the Internet, we succeeded in its identification as a saddleback caterpillar. Tracing its transatlantic importation was the most difficult.

CONCLUSIONS

Saddleback caterpillars can be imported to France and carried across the Atlantic Ocean on house or garden plants especially Areca trees. French garden store owners should be informed about this risk and should check and treat host plants (especially Areca trees) at the arrival time.

The venom of the Lonomia caterpillar: an overview

Contact with the Lonomia caterpillar causes numerous accidents, especially in Venezuela and the southern region of Brazil, where it is considered a public health problem. The Lonomia obliqua venom causes disseminated intravascular coagulation and a consumptive coagulopathy, which can lead to a hemorrhagic syndrome. The venom of Lonomia achelous also causes hemorrhage, but through increased fibrinolysis. In vivo and in vitro studies have shown that the venom of the Lonomia caterpillar contains several toxins with procoagulant, anticoagulant and antithrombotic activities. These toxins also affect the endothelium. The recent construction of cDNA libraries of the transcripts from L. obliqua bristles enables the use of biotechnological approaches to study the venom. This paper presents an overview of the biochemical and biological properties of Lonomia caterpillar venom, discussing aspects of human accidents, experimental envenomation, toxins and targets and future perspectives.

Systemic immediate allergic reactions to arthropod stings and bites

Most of the encounters with biting and stinging insects result in more or less pronounced localized reactions. Typically, urticarial wheals and papular reactions are observed. Less often local bullous or hemorrhagic or disseminated papular reactions, particularly in children and immunologically naive adults, may be seen. With the exception of bee and wasp venom allergies, immediate-type allergic reactions to arthropod stings and bites are rare. Systemic IgE-mediated hypersensitivity has also been reported from additional hymenoptera species, e.g. hornets, bumble bees and ants. Rare are systemic reactions to mosquitoes, flies or kissing bugs and exceptional from ticks, bed bugs, moths, caterpillars and spiders. A major problem is the often lacking standardization of extracts for skin testing and for the determination of specific IgE. Some of the allergens have been characterized and few of them synthesized using recombinant techniques. Most investigations have been made with whole-body extracts or extracts from salivary glands, while desensitization has rarely been attempted. Currently, primary prevention by avoidance of stings and bites, and adequate instruction of sensitized individuals in the use of emergency drugs are mandatory.

Severe tongue necrosis associated with pine processionary moth (Thaumetopoea wilkinsoni) ingestion in three dogs

The pine processionary moth (Thaumetopoea wilkinsoni) is an insect of medical significance in the eastern Mediterranean. This report describes three exposure cases in dogs due to ingestion of this moth's caterpillars in Israel. All three dogs were observed in direct contact with caterpillars or pinecones in infested gardens. The disease course and progression of signs were acute in all three cases, and included vomiting and severe tongue swelling. Physical examination findings included hyperthermia, tachypnoea, respiratory distress, cyanosis and tongue oedema, labial angioedema, ptyalism, bilateral submandibular lymphadenomegaly and conjunctivitis. Severe tongue necrosis and sloughing of its distal portion occurred 2-5 days after admission to the hospital. All dogs recovered and were discharged within 2-7 days of admission. Two staff members, attending one of the dogs, experienced an itchy rash and wheals on their arms, wrists and necks. To the best of our knowledge, this should be the first report of severe oral lesions and tongue necrosis due to contact with T. wilkinsoni caterpillars.