Thaumetopoein: an urticating protein from the hairs and integument of the pine processionary caterpillar (Thaumetopoea pityocampa Schiff., Lepidoptera, Thaumetopoeidae)

Exploring oak processionary caterpillar induced lepidopterism (part 2): ex vivo bio-assays unmask the role of TRPV1

As human skin comes into contact with the tiny hairs or setae of the oak processionary caterpillar, Thaumetopoea processionea, a silent yet intense chemical confrontation occurs. The result is a mix of issues: skin rashes and an intense itching that typically lasts days and weeks after the contact. This discomfort poses a significant health threat not only to humans but also to animals. In Western Europe, the alarming increase in outbreaks extends beyond areas near infested trees due to the dispersion of the setae. Predictions indicate a sustained rise in outbreaks, fueled by global changes favoring the caterpillar's survival and distribution. Currently, the absence of an efficient treatment persists due to significant gaps in our comprehension of the pathophysiology associated with this envenomation. Here, we explored the interaction between the venom extract derived from the setae of T. processionea and voltage- and ligand-gated ion channels and receptors. By conducting electrophysiological analyses, we discovered ex vivo evidence highlighting the significant role of TPTX1-Tp1, a peptide toxin from T. processionea, in modulating TRPV1. TPTX1-Tp1 is a secapin-like peptide and demonstrates a unique ability to modulate TRPV1 channels in the presence of capsaicin, leading to cell depolarization, itch and inflammatory responses. This discovery opens new avenues for developing a topical medication, suggesting the incorporation of a TRPV1 blocker as a potential solution for the local effects caused by T. processionea.

Intermediate Uveitis with Cystoid Macular Edema as Presentation of Retained Caterpillar Hair in the Vitreous Cavity

PURPOSE

To report an unusual case of retained caterpillar hair in the vitreous cavity presenting as recurrent Intermediate Uveitis with cystoid macular edema.

METHOD

Case Report.

RESULTS

A 40-year-old male presented to our uveitis clinic with recurrent episodes of redness and diminution of vision in his left eye for 3 years. He was diagnosed and treated elsewhere as a case of recurrent intermediate uveitis and was referred to our center for a second opinion to initiate immunosuppressive therapy. A detailed history revealed that a caterpillar had fallen into his left eye 3 years back, followed by severe irritation, pain, and redness. He received topical antibiotics and corticosteroids, and retained caterpillar hair was removed from the ocular surface. During the last 3 years, the patient had multiple episodes of inflammation despite being treated with oral and topical corticosteroids. At the current visit, a meticulous clinical examination at our centre revealed multiple, migrated, retained caterpillar hair in the vitreous cavity. The patient was diagnosed with Ophthalmia Nodosa (Type V) and managed with surgical intervention (vitreous surgery). The case highlights an unusual presentation of ON and the role of pars plana vitrectomy in its successful management.

CONCLUSION

We highlight a rare and unusual presentation of ophthalmia nodosa and its successful management.

Zootoxins and Domestic Animals: A European View

Zootoxins are produced by venomous and poisonous species and are an important cause of poisoning in companion animals and livestock in Europe. Little information about the incidence of zootoxin poisoning is available in Europe, with only a few case reports and review papers being published. This review presents the most important zootoxins produced by European venomous and poisonous animal species responsible for poisoning episodes in companion animals and livestock. The main zootoxin-producing animal species, components of the toxins/venoms and their clinical effects are presented. The most common zootoxicoses involve terrestrial zootoxins excreted by the common toad, the fire salamander, the pine processionary caterpillar, and vipers. The lack of a centralized reporting/poison control system in Europe makes the evaluation of the epidemiology of zootoxin-induced poisonings extremely difficult. Even if there are many anecdotal reports in the veterinary community about the exposure of domestic animals to terrestrial and marine zootoxins, the number of published papers regarding these toxicoses is low. Climate change and its consequences regarding species distribution and human-mediated transportation are responsible for the emerging nature of some intoxications in which zootoxins are involved. Although new venomous or poisonous animal species have emerged in regions where they were previously unreported, zootoxins produced by native species remain the main concern in Europe. The diversity of poisonous and venomous animal species and the emerging nature of certain poisonings warrant the continuous update to such knowledge by veterinary professionals and animal owners. This review offers an overview about zootoxin-related poisonings in domestic animals in Europe and also provides important information from a health perspective.

Human exposure to larvae of processionary moths in France: study of symptomatic cases registered by the French poison control centres between 2012 and 2019

CONTEXT

Contact with the setae of larvae (caterpillars) of pine or oak processionary moths could induce urticarial or allergic reactions in humans. These species are present in France and presently expanding towards highly populated areas due to climate change and/or human-mediated translocations. We aimed to describe the symptomatic cases of exposure to processionary larvae in France.

METHODS

We conducted a retrospective study of symptomatic cases of exposure to processionary larvae registered by the French poison control centres between 1 January 2012 and 31 July 2019. We reviewed all medical records coded with the agent "larvae".

RESULTS

Of the 1274 included cases, 59% and 27% corresponded to pine and oak processionary larvae, respectively; the 14% remaining cases concerned unspecified processionary larvae. While the annual number of cases due to pine processionary larvae fluctuated during the study period, cases associated with oak processionary larvae increased steadily. Most of the annual cases occurred between January and May for pine processionary larvae, and April and August for oak processionary larvae (with a peak in March or June, respectively). Among the 1022 cases for which information was available, the sex ratio was 1.2 and the median age was 11 years old. Skin symptoms were reported by 96,3% of the cases, such as pruritus or urticaria. The severity was mild in 96.3% of cases, moderate in 3.5%, and severe in 0.2% (two cases). Ocular or oral exposures led more frequently to severe symptoms than dermal ones (respectively 31% and 18% vs. 2% of cases, p < 10^-3).

CONCLUSION

Since processionary moth larvae exposure is a growing health concern, which can cause severe injuries particularly after ocular or oral exposures, the population, and the professionals should be informed of existing recommendations to avoid exposure and measures to be taken after being exposed.

Ophthalmia nodosa secondary to multiple intraocular caterpillar hairs in a 2-year-old girl

A 2-year-old girl presented with pain, itching, photophobia, and tearing in her left eye. These symptoms started after contact with a caterpillar. The patient was initially taken to another hospital, where the local ophthalmologist prescribed topical prednisolone acetate 1%, a topical antibiotic, and cyclopentolate 1% eye drops. However, 3 weeks later, the patient presented to our hospital with no symptomatic improvement. Slit-lamp examination showed moderate conjunctival injection and diffuse superficial punctate corneal epithelial erosions with numerous caterpillar hairs embedded in the bulbar and tarsal conjunctiva, and in the superficial and deep corneal stroma, extending into the anterior chamber (AC). In addition, the AC had 2+ cells with caterpillar hairs on the iris surface. The lens was clear, and the fundus examination was normal. The patient underwent AC wash and setae removal under general anesthesia; this was repeated 4 months later when symptoms recurred owing to retained setae. There was no evidence of any additional setae or ocular inflammation in 8 months of follow-up, and symptoms resolved completely. Caterpillar hairs can migrate intraocularly and induce an ocular inflammatory response. Immediate and thorough irrigation, continued scrupulous examinations for any retained setae, and meticulous setae extraction are crucial for treating this condition.

Caterpillar Venom: A Health Hazard of the 21st Century

Caterpillar envenomation is a global health threat in the 21st century. Every direct or indirect contact with the urticating hairs of a caterpillar results in clinical manifestations ranging from local dermatitis symptoms to potentially life-threatening systemic effects. This is mainly due to the action of bioactive components in the venom that interfere with targets in the human body. The problem is that doctors are limited to relieve symptoms, since an effective treatment is still lacking. Only for Lonomia species an effective antivenom does exist. The health and economical damage are an underestimated problem and will be even more of a concern in the future. For some caterpillar species, the venom composition has been the subject of investigation, while for many others it remains unknown. Moreover, the targets involved in the pathophysiology are poorly understood. This review aims to give an overview of the knowledge we have today on the venom composition of different caterpillar species along with their pharmacological targets. Epidemiology, mode of action, clinical time course and treatments are also addressed. Finally, we briefly discuss the future perspectives that may open the doors for future research in the world of caterpillar toxins to find an adequate treatment.

Venomous caterpillars: From inoculation apparatus to venom composition and envenomation

Envenomation by the larval or pupal stages of moths occurs when the victim presses their hairs. They penetrate the subcutaneous tissue, releasing toxins such as proteolytic enzymes, histamine and other pro-inflammatory substances. Cutaneous reactions, including severe pain, oedema and erythema are frequent local manifestations of caterpillar envenomation, but, in some cases, the reactions can evolve into vesicles, bullae, erosions, petechiae, superficial skin necrosis and ulcerations. Alternatively, some individual can develop allergic reactions, renal failure, osteochondritis, deformity and immobilization of the affected joints and intracerebral bleeding. Caterpillars produce venom to protect themselves from predators; contact with humans is accidental and deserves close attention. Their venoms have not been well studied, except for toxins from some few species. The present review brings together data on venomous caterpillars of moths, primarily addressing the available literature on diversity among the different families that cause accident in humans, the structures used in their defense, venom composition and clinical aspects of the envenomations. Understanding the molecular mechanisms of action of caterpillars' toxins may lead to the development of more adequate treatments.

Proteome Analysis of Urticating Setae From Thaumetopoea pityocampa (Lepidoptera: Notodontidae)

Thaumetopoea pityocampa (Denis & Schiffermüller) (Lepidoptera: Notodontidae) is harmful to conifer trees because of defoliation and to public health because of the release of urticating setae from the caterpillars. Contact with setae by humans and domestic animals induces dermatitis, usually localized to the exposed areas. Recent studies demonstrated the presence of a complex urticating mechanism where proteins present in the setae may play a role as activators of immune responses. Yet, limited information is available at present about the proteins occurring in the setae of T. pityocampa. Using a refined method for protein extraction from the setae, and a combination of liquid chromatography tandem-mass spectrometry (LC-MS/MS), de novo assembly of transcriptomic data, and sequence similarity searches, an extensive data set of 353 proteins was obtained. These were further categorized by molecular function, biological process, and cellular location. All the 353 proteins identified were found to match through BLAST search with at least one Lepidoptera sequence available in databases. We found the previously known allergens Tha p 1 and Tha p 2 described from T. pityocampa, as well as enzymes involved in chitin biosynthesis, one of the principal components of the setae, and serine proteases that were responsible for inflammatory and allergic reactions in other urticating Lepidoptera. This new proteomic database may allow for a better understanding of the complexity of allergenic reactions due to T. pityocampa and to other Lepidoptera sharing similar defense systems.

A Hairy Affair: Ophthalmia nodosa Due to Caterpillar Hairs

PURPOSE

To study different clinical presentations, course, and final outcomes of ophthalmia nodosa, a rare disease caused by hairs of the caterpillar.

METHODS

A total of 29 eyes of 17 patients with the disease presenting to our institute in 2013 were included.

RESULTS

Patients presented with foreign body sensation (94%), photophobia (88%), lacrimation (82%), redness (94%), and eyelid edema (82%). Hairs were found in the conjunctiva (89.6%), cornea (65.5%), and even anterior chamber (3.4%). There was a conjunctival nodule in two eyes (6.8%). Resolution of symptoms occurred in 3-21 days. Treatment included topical steroids, cycloplegia, and removal of hairs with forceps. More than one sitting was required in 17 eyes (62.9%) due to reactional inflammation, precluding visualization of all the hairs.

CONCLUSIONS

Ophthalmia nodosa is a relatively rare condition with subtle findings, which can be missed, causing considerable discomfort to the patient if the hairs are not removed.

Diagnostic use of recombinant Tha p 2 in the allergy to Thaumetopoea pityocampa

Thaumetopoea pityocampa causes allergies and skin and ocular lesions. No commercial tools are currently available for the clinical diagnosis of this allergy. We aimed to develop an in vitro method for the diagnosis of this allergy to avoid patients undergoing in vivo tests with insect extracts. Recombinant Tha p 2 was produced and used in an ELISA validated with 15 allergic patients. Subsequently, 42 subjects recruited from a random sampling cross-sectional study were analysed. The ELISA sensitivity and specificity were 93.3% and 100%, respectively, for the allergic patients and 71.4% and 95.3%, respectively, for the epidemiological study. The positive ELISA results correlated with the skin prick test areas with the whole body and the setae extracts. Professional exposure and short latency of symptoms onset were risk factors for a positive result in the ELISA. In conclusion, our ELISA is very useful for T. pityocampa allergy diagnosis and for epidemiologic testing.

The allergenic protein Tha p 2 of processionary moths of the genus Thaumetopoea (Thaumetopoeinae, Notodontidae, Lepidoptera): Characterization and evolution

The allergenic Tha p 2 protein has been extracted recently from the urticating setae of the pine processionary moth Thaumetopoea pityocampa. In the present paper, we test for the occurrence of this protein in other Thaumetopoeinae, with a particular focus on members of the genus Thaumetopoea, as well as unrelated moth species, to better understand the physicochemical properties of the protein, the nature of encoding genes and their evolutionary history. Tha p 2 is encoded by the intronless gene Tha p 2 that is restricted to the processionary moths (Thaumetopoeinae, Notodontidae, Lepidoptera). Most of the species present two isoforms of Tha p 2 that can be interpreted as the result of heterozygosity in the single gene. The only exception is represented by Thaumetopoea wilkinsoni, in which 20 different isoforms occur in a single specimen, leading to the conclusion that, at least in this species, multiple copies of Tha p 2 exist. Serine, glycine, cysteine and leucine are abundant in Tha p 2, a protein well conserved among processionary moths. The predicted secondary structures of Tha p 2 indicate the presence of 3 α-helices and six β-barrels. Finally, the evolution of the gene and the protein was characterized by a combination of positive and negative selection, with the latter being more evident.

Mast cells respond to urticating extract from lepidoptera larva Morpheis ehrenbergii in the rat

Mast cells and histamine participate in toxic effects of hairs from some caterpillars. This study reports that a crude extract of Morpheis ehrenbergii caterpillar hairs induces in vitro mast cells activation, triggers the release of histamine and causes a rapid urticarial reaction in the rat skin. Heating of the extract abolishes the inflammatory reaction. These results suggest that the use of antihistamines may improve the adverse skin reactions caused by the Mexican caterpillar M. ehrenbergii.

Skin Reactions to pine processionary caterpillar Thaumetopoea pityocampa Schiff

Pine caterpillar, Thaumetopoea pityocampa Schiff, is a phyto- and xylophagous lepidopteran, responsible for the delay in the growth or the death of various types of pines. Besides nature damage, pine caterpillar causes dermatological reactions in humans by contact with its irritating larvae hairs. Although the dermatitis occurs among outdoor professionals, it is primarily extraprofessional. Contamination generally occurs in pinewoods, rarely in cities. Means of contamination comprise direct contact with the nest or the processional caterpillar and indirect contact with air dispersed hairs. The dermatitis is generally observed in late spring and particularly from April to June, among campers and tourers. The eruption has its onset 1-12 hours after contact with the hairs and presents with intense and continuous itching. Morphologically, it is strophulus-like and consists of papulous, excoriated, and pinkish lesions on an oedematous base. Diagnosis is usually straightforward. The pathogenetic mechanism of the affection is mechanical, pharmacological, and allergic in nature. Besides skin, T. pityocampa Schiff can involve the eyes and rarely the airways. Despite the considerable damages to humans and nature, pine caterpillar infestation is an underestimated problem; medical literature lists few studies, and often relevant information is referred to local media and popular wisdom.

Equine amnionitis and fetal loss: mare abortion following experimental exposure to Processionary caterpillars (Ochrogaster lunifer)

REASONS FOR PERFORMING STUDY

In Australia, there have been recent reports of unusual abortions in mid- to late-gestation mares. These were clinically distinct from other recognised causes of pregnancy loss and the term 'equine amnionitis and fetal loss' (EAFL) was adopted to describe this syndrome. Initial investigations concluded that possible causal factors included the presence on affected stud farms of Processionary caterpillars (Ochrogaster lunifer).

OBJECTIVES

To determine if exposure of pregnant mares to Processionary caterpillars or their shed exoskeletons can induce EAFL.

METHODS

Processionary caterpillars and their shed exoskeletons were collected and stored frozen. Mid-gestation mares were dosed with a slurry of caterpillars or shed exoskeleton by nasogastric intubation. Their clinical responses and times to abortion were recorded. All aborted fetuses were autopsied and samples taken for bacteriological and virological culture and histopathology.

RESULTS

Intubating mares in mid-pregnancy with preparations of either whole Processionary caterpillars or shed caterpillar exoskeletons induced abortion with few impending clinical signs. The gross pathological and bacteriological findings of the aborted fetuses were similar to those observed in field cases of EAFL.

POTENTIAL RELEVANCE

Possible exposure to Processionary caterpillars should be considered when examining cases of fetal loss in the mare. The present results provide a starting point to further explore the aetiology and pathogenesis of EAFL.

[Skin reactions on exposure to the pine processionary caterpillar (Thaumetopoea pityocampa)]

The pine processionary caterpillar is the larval form of the Thaumetopoea pityocampa moth. Mediterranean forests regularly suffer plagues of this insect, which has been moving north as a result of global warming. When the small urticating hairs that develop during the last 3 larval stages are shed and can become airborne. If they come in contact with skin, they can cause a variety of reactions, notably contact urticaria and papular rashes. Irritation can also occur if the hairs lodge in the mucosa of the conjunctiva or in the respiratory tract. Several cases of anaphylactic reactions have been reported in recent years. Mechanical (irritative) mechanisms may be involved in the pathogenesis of lesions, or immunoglobulin E-mediated allergic hypersensitivity reactions may be implicated when the process is rapid, recurrent, and progressively more severe.

Urticating hairs in arthropods: their nature and medical significance

The ecological phenomenon of arthropods with defensive hairs is widespread. These urticating hairs can be divided into three categories: true setae, which are detachable hairs in Lepidoptera and in New World tarantula spiders; modified setae, which are stiff hairs in lepidopteran larvae; and spines, which are complex and secretion-filled structures in lepidopteran larvae. This review focuses on the true setae because their high density on a large number of common arthropod species has great implications for human and animal health. Morphology and function, interactions with human tissues, epidemiology, and medical impact, including inflammation and allergy in relation to true setae, are addressed. Because data from epidemiological and other clinical studies are ambiguous with regard to frequencies of setae-caused allergic reactions, other mechanisms for setae-mediated disease are suggested. Finally, we briefly discuss current evidence for the adaptive and ecological significance of true setae.

Systemic allergic reaction to tree processionary caterpillar in children

Contact with the tree processionary caterpillar or ingestion/inhalation of its airborne toxin-containing hairs and spines may cause a direct histamine-releasing or IgE-mediated allergic reaction in humans. The most common manifestations are urticaria and dermatitis; systemic manifestations such as respiratory involvement and anaphylaxis have been reported mainly in foresters. We describe a 12-year-old child who was presented to the emergency department with systemic allergic reaction (pruritic rash, conjunctival hyperemia, dyspnea, and wheezing), which eventually proved to be due to exposure to the pine tree processionary caterpillar. The diagnosis was made only after the child's repeated exposure to the caterpillar. Tree processionary caterpillar should be added to the list of causes of systemic allergic reactions in children, especially in endemic areas, and medical staff should be alerted the range of clinical manifestations to ensure prompt diagnosis and treatment.

Isolation and partial characterization of proteins with vasodegenerative and proinflammatory properties from the egg-nests of Hylesia metabus (Lepidoptera: Saturniidae)

The Hylesia genus comprises a group of Neotropical moths ubiquitous in the Americas from Arizona to Argentina. One of the species of the Hylesia genus in Venezuela, French Guyana, and Trinidad has been identified as Hylesia metabus (Cramer 1775) (Lepidoptera: Saturniidae). In Venezuela, these moths are found in abundance in the mangrove (Avicennia spp.) swamps surrounding the Gulf of Paria and the Orinoco Delta in the eastern part of the country. During the mating season, the female adults shed copious amounts of urticating setae in the air, producing a severe papulovesicular dermatitis among the population in the affected areas. The females also use their urticating setae to protect the eggs during the hatching period. In the current study, we have isolated and partially characterized proteins with proinflammatory properties from the urticating setae in the egg-nests by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and anionic exchange-high-performance liquid chromatography (HPLC). We also have studied the biological response of the egg-nest extract and the HPLC purified fractions by inoculation in guinea pigs; and, analyzing the tissue samples by means of histopathological methods. The results of this study show that the extracted venom and HPLC purified subcomponents give rise to an intense inflammatory reaction characterized by massive infiltration of inflammatory cells, echymoses, and vascular degeneration. Chromatographic separation showed that the venom was made up of proteins having selectively vasodegenerative-fibrinolytic or proinflammatory-quimotactic properties.

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.

Life-threatening facial edema due to pine caterpillar mimicking an allergic event

BACKGROUND

Approximately 150 species of Lepidoptera have been described as causing damage to human skin. One of these species is the pine processionary caterpillar, which is responsible for dermatitis, contact urticaria, ocular lesions and rarely respiratory signs and anaphylactic reactions through IgE-mediated or non-IgE-mediated mechanisms. We report a pediatric case of severe orofacial edema mimicking an allergic reaction after ingestion of a pine processionary caterpillar; urgent airway intubation was required.

CASE REPORT

A 15-month-old boy was sleeping under a pine tree when his mother noted a pine caterpillar on his tongue. Because of rapidly developing facial swelling and respiratory distress, the infant was first taken to a local hospital where he received intravenous dexamethasone and pheniramine hydrogen maleate. On arrival at our emergency department, diffuse swelling and edema involving the tongue, perioral, nasal and perimandibular regions, and neck was noted, requiring urgent orotracheal intubation. There were no findings of anaphylaxis. The results of skin prick tests and specific IgE to common aero- and food allergens were negative. A skin prick test with extract of pine caterpillar was also negative. Prednisolone and pheniramine hydrogen maleate were administered for 7 days. The child gradually improved and was successfully extubated 4 days later.

CONCLUSION

Although oral contact with a pine processionary caterpillar in the form of ingestion is rare, it may cause significant local reaction and airway compromise mimicking an allergic event. In this situation, early intubation to maintain airway patency is a life-saving measure.

Allergy to pine processionary caterpillar (Thaumetopoea pityocampa) in children

Contact with pine processionary caterpillar (Thaumetopoea pityocampa) induces dermatitis usually located in exposed areas through a toxic-irritative mechanism. Over the last few years an immediate hypersensitivity mechanism have mainly been demonstrated in adult patients. However, there are few studies carried out in children.

OBJECTIVE

To evaluate a group of 16 children who experienced allergic reactions after exposure to pine processionary caterpillar.

PATIENTS AND METHODS

All patients underwent allergy testing through skin prick test. Serum specific IgE determination was performed by EAST technique. The molecular mass of the IgE -binding bands was studied by SDS-PAGE Immunoblotting.

RESULTS

Skin prick test with the caterpillar extract was positive in all patients. Specific IgE was positive (higher than 0.35 kU/L) in 15 patients' sera. Western blotting showed several IgE-binding bands with molecular mass values ranging from 17.5 to 168 kDa. Electrophoretic mobility of some of the relevant allergens was related to the conditions of sample preparation (reduced or non-reduced).

CONCLUSIONS

The results of this study demonstrate the existence of an allergic IgE-mediated mechanism caused by pine processionary caterpillar proteins. Airborne urticating hairs of this animal should be considered as seasonal inhalant allergen, which is able to induce allergic pathologies in children who frequent pine areas.

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.

Occupational immunologic contact urticaria from pine processionary caterpillar (Thaumetopoea pityocampa): experience in 30 cases

Cutaneous lesions caused by the pine processionary caterpillar Thaumetopoea pityocampa (TP) are frequent in pinewood areas. In the present study, 30 patients diagnosed with occupational immunologic urticaria from this caterpillar were included. Immediate hypersensitivity was demonstrated by performing prick and IgE-immunoblotting tests. Workers were grouped according to their common tasks. Occupations at risk of exposure to TP were pine-cone collectors/woodcutters (14), farmers/stockbreeders (8), other forestry personnel (4), construction workers (2), residential gardeners (1) and entomologists (1). Besides contact urticaria, angioedema (60%), papular lesions of several days of evolution (30%) and anaphylactic reactions (40%) were also detected. The most frequently detected molecular weight bands by immunoblot were 15 (70%), 17 (57%) and 13 kDa (50%). The appearance of isolated bands corresponds with the least serious cases. Only 8 subjects had bands higher than 33 kDa, which was present in the 3 most severe cases of anaphylactic reactions. By presenting these cases, we wish to offer the largest series reported so far of occupational immunologic contact urticaria caused by TP. We include the first cases described in certain occupations, some of them not directly related to forestry work. Pine-cone or resin collectors, woodcutters, farmers and stockbreeders were the most frequently and severely affected workers.

Non-occupational allergy caused by the pine processionary caterpillar (Thaumetopoea pityocampa)

Contact with the pine processionary caterpillar induces dermatitis, usually located in exposed areas, and, less frequently, ocular lesions through a toxic-irritative mechanism. Recently, the existence of an immediate hypersensitivity mechanism has been demonstrated, mainly in occupationally exposed patients.

OBJECTIVE

To present four patients who experienced allergic reactions (urticaria-angioedema and rhinitis-asthma) after non-occupational exposure to pine processionary caterpillar.

PATIENTS AND METHODS

The four patients underwent allergy testing through skin prick tests (SPT), specific IgE detection and SDS-PAGE immunoblotting. One patient also underwent a specific bronchial challenge test with the pine processionary antigen.

RESULTS

In all patients, both SPT with the caterpillar extract and specific IgE were positive. Western blotting showed several IgE-binding bands with molecular mass values ranging from 18 to 107 kDa. A shift in the electrophoretic mobility of some of the relevant allergens occurred under the presence of a reductive agent (beta -mercaptoethanol). The specific bronchial challenge test with pine processionary antigen performed in one of the patients also produced positive results.

CONCLUSIONS

The results of this study show an immunologic IgE-mediated immediate hypersensitivity mechanism in these reactions. The processionary caterpillar's airborne urticating hairs or spicules should be considered, at least in some locations, not only as contact and occupational allergens, but also as seasonal aeroallergens.

Cutaneous reactions to pine processionary caterpillar (Thaumetopoea pityocampa) in pediatric population

Cutaneous lesions caused by pine processionary caterpillar (Thaumetopoea pityocampa, TP) are frequent in pinewood areas. However, no epidemiological studies have been performed so far in the pediatric population. In this study, we evaluated the relevance of reactions to pine processionary caterpillar in the pediatric population of our environment and determined the possible role of an IgE-mediated mechanism. A questionnaire was developed and given to 1,101 children and adolescents ranging from 3 to 17 years of age from rural areas with large pine forests. A total of 653 questionnaires were answered by the children or their parents. The search for immunoglobulin E (IgE)-mediated cases was based on the presence of a suspected reaction to caterpillar and confirmed by in vivo (skin prick) and in vitro (immunoblotting) tests. Sixty of the 653 people interviewed (9.18%) identified a cutaneous reaction from exposure to the processionary caterpillar. Within this group only four cases (6.7%) were because of an IgE-mediated mechanism. The predominant clinical feature of these patients with allergy to caterpillar was contact urticaria. We present the first study of cutaneous reactions to pine processionary caterpillar in a large pediatric population. This is a frequent pathology in pinery zones and only in a minority of the cases are because of an IgE-mediated allergic mechanism. This fact contrasts with studies in adults, where this percentage is much greater.

Role of trail pheromone in foraging and processionary behavior of pine processionary caterpillars Thaumetopoea pityocampa

Although caterpillars of Thaumetopoea pityocamnpa may mark their pathways with silk, this study shows that the material is essential to neither the elicitation nor maintenance of trail-following or processionary behavior. Trail following is dependent upon a pheromone the caterpillars deposit by brushing the ventral surfaces of the tips of their abdomens against the substate. Earlier instars are strongly bound to their trail system; in the laboratory, caterpillars followed circular trails continuously for as long as 12 hr before breaking away from them. The trail pheromone is long-lived and soluble in nonpolar solvents, but its volatilization or degradation allows the caterpillars to distinguish new from aged trails. In contrast to trail following, processionary behavior, the head-to-tail, single-file movement of the caterpillars is dependent on neither silk nor the trail pheromone. Stimuli associated with setae found on the tip of the abdomen of the precedent caterpillar serve to hold processions together, and such stimuli take priority over those associated with either the trail pheromone or silk. Although the caterpillars discern trail strength and choose stronger over weaker trails, the trail marking system of the processionary caterpillar appears less sophisticated than those of other, previously studied species of social caterpillars, and colonies are relatively inefficient in abandoning exhausted feeding sites in favor of new food finds. In laboratory studies, females were more likely to lead processions than males, and leaders, regardless of gender, expended more energy in locomotion than followers.

Isolation and characterization of Tha p 1, a major allergen from the pine processionary caterpillar Thaumetopoea pityocampa

BACKGROUND

Pine processionary caterpillars induce dermatitis by a toxic-irritative mechanism. The existence of true allergic reactions to allergens from these caterpillars has been recently demonstrated by positive immediate skin prick tests and specific IgE determination by immunoblotting using crude larval extracts. The aim of this work was to purify allergens from the crude larval extract in order to characterize IgE-binding proteins from these caterpillars.

METHODS

Allergens were separated by ethanol gradient fractionation and reversed phase HPLC. The N-terminal amino acid sequence of a selected allergen was obtained after SDS-PAGE and transfer. The clinical relevance of this allergen was measured using sera from patients allergic to caterpillar.

RESULTS

An allergen with a molecular weight close to 15 kDa was purified. It was recognized by 9 out of 11 allergic patients (82%). Its N-terminal amino acid sequence had no homologies to any other protein already described in data bases. For this reason, no information about its biological function could be obtained.

CONCLUSIONS

This 15-kDa IgE-binding protein is a major caterpillar allergen and shows no homologies to other insect allergens already described.

Pine processionary caterpillar allergenicity increases during larval development

BACKGROUND

In European countries, pine processionary caterpillar (Thaumetopoea pityocampa) is one of the species of Lepidoptera able to affect humans. Its allergenicity has been demonstrated in previous studies. However, in all of them larval extract in the fifth stage of development has been used as antigen. Therefore, allergenicity of other larval stages was unknown. The objective of our study was to detect allergenic changes of pine processionary caterpillar during larval development.

METHODS

Pine processionary caterpillar extracts in all larval stages were analyzed by SDS-PAGE. Immunoblotting was performed using patient sera with suggestive history of allergy and a positive prick test.

Arthropod allergens and human health

Many species of arthropods are the sources of potent allergens that sensitize and induce IgE-mediated allergic reactions in humans. Most of these arthropod allergens are proteins, and the allergic response mechanism to these allergens is the same as it is for allergens from other sources such as plant pollens, molds, and foods. Aside from ingestion of crustaceans (shrimp, lobster), among arthropods, humans have the greatest contact with insects and mites, and as a result allergies to these two groups of arthropods have been the most frequently reported. Because of the large number of people affected by allergic reactions to stinging insects, cockroaches, and dust mites, many allergens of these organisms have been extensively studied, purified, and immunobiochemically characterized and for some recombinant allergens, produced. Cocktails of these recombinant allergens have the potential for use in diagnosis and immunotherapy. In this chapter, we review the insects and mites that induce allergic reactions. Where the information exists, the immunobiochemical characterization of the allergens and the frequency of sensitivity or clinical reactivity in the human population are also reviewed. As background, the beginning of this review includes sections that define allergens, explain the allergic reaction mechanism, and describe the methods for naming allergens.

Caterpillar setae-induced acute anterior uveitis: a case report

PURPOSE

To report uveitis secondary to ocular penetration of caterpillar hairs (setae).

METHODS

Case report. A documented attack of acute anterior uveitis was caused by initially overlooked penetration of caterpillar setae.

RESULTS

A 66-year-old man presenting with unilateral hypertensive keratouveitis was treated with antiherpes simplex medication (along with local anti-inflammatory and cycloplegic agents) after anterior chamber paracentesis and serologic testing. Laboratory testing was negative. Resolution occurred after 5 days, and corneal clearing showed a predescemetic caterpillar seta.

CONCLUSION

Patient history taken in an anterior uveitis setting should include gardening habits and searching for possible exposure to insects or arachnids.

Caterpillar setae in the deep cornea and anterior chamber

PURPOSE

To report a case of caterpillar setae embedded in the deep cornea and anterior chamber.

METHODS

A 26-year-old man was struck in his right eye by a caterpillar (Dendrolimus punctatus walker). Severe conjunctival injection, chemosis, and erosion of the cornea developed immediately. Numerous setae fragments were found to be embedded into the palpebral conjunctiva and deep cornea, extending into the anterior chamber near the anterior iris surface.

RESULTS

After partial removal of the setae under a microscope, the inflammation subsided and visual acuity improved to RE: 20/20.

CONCLUSION

Caterpillar setae are sharp enough to penetrate the cornea and extend into the anterior chamber.

Hypertension and abdominal pain: uncommon presentation after exposure to a pine caterpillar

The pine caterpillar Thaumatopoea wilkinsoni is found in pine woods all over Israel. Contact with its hair usually results in local reactions. Systemic reactions after contact with caterpillar hairs are known in other caterpillar species, but have been described only once after contact with T. wilkinsoni. We describe a group of adolescents who were exposed to T. wilkinsoni while camping in a pine wood. Three of them were referred to an emergency department. They had severe pruritus, pain and edema at the contact sites, with papular and urticarial rashes. Two of the patients had abdominal pain and one patient had hypertension for several hours. The hypertension resolved spontaneously.

CONCLUSION

Skin eruptions are the most common manifestations of T. wilkinsoni contact, however, although systemic manifestations are rare, abdominal pain and hypertension may occur.

Allergy to the pine processionary caterpillar (Thaumetopoea pityocampa)

BACKGROUND

The contact with the pine processionary caterpillar (Thaumetopoea pityocampa) induces dermatitis and ocular lesions by a mechanic and toxic mechanism. However, IgE-mediated hypersensitivity to this caterpillar has been demonstrated in two recent studies.

OBJECTIVE

To find if an IgE-mediated mechanism was operative among patients with suspected previous reactions to processionary caterpillars, particularly exposed workers.

METHODS

Fifty-five patients were studied by skin prick test (SPT), and specific IgE detection by immunoblotting.

RESULTS

A total of 58.18% patients had a positive SPT for caterpillar extract. Positive SPT patients had more generalized cutaneous reactions (47%) and oedema (50%) as well as a shorter latency period (mean, 36 min) and duration of cutaneous lesions (mean, 26 h) than the patients with negative SPT. A total of 60% of the positive SPT patients had occupational exposure to the processionary caterpillar. The occupationally exposed workers showed significant symptoms from October to December. The anaphylactic reactions only appeared in allergic patients with occupational exposure and were also more frequent from October to December. These patients with anaphylactic reactions had a major size of SPT and the exercise was found in them to be a variable that increased the symptoms. The IgE immunoblot detected in the caterpillar extract several reactive bands with apparent molecular weights from to 35-4 kDa in 72% of the cases with positive SPT.

CONCLUSIONS

Allergic reactions to T. pityocampa urticating hairs have different clinical characteristics than those induced by a toxic-irritative mechanism and are more frequent than suspected. Allergic reactions to this caterpillar among occasional visitors to pine-wood areas, and particularly in pine-forest workers, should be taken into consideration by allergists.