The venom of the Lonomia caterpillar: an overview

Phylogeny, envenomation syndrome, and membrane permeabilising venom produced by Australia's electric caterpillar Comana monomorpha

Zygaenoidea is a superfamily of lepidopterans containing many venomous species, including the Limacodidae (nettle caterpillars) and Megalopygidae (asp caterpillars). Venom proteomes have been recently documented for several species from each of these families, but further data are required to understand the evolution of venom in Zygaenoidea. In this study, we examined the 'electric' caterpillar from North-Eastern Australia, a limacodid caterpillar densely covered in venomous spines. We used DNA barcoding to identify this caterpillar as the larva of the moth Comana monomorpha (Turner, 1904). We report the clinical symptoms of C. monomorpha envenomation, which include acute pain, and erythema and oedema lasting for more than a week. Combining transcriptomics of venom spines with proteomics of venom harvested from the spine tips revealed a venom markedly different in composition from previously examined limacodid venoms that are rich in peptides. In contrast, the venom of C. monomorpha is rich in aerolysin-like proteins similar to those found in venoms of asp caterpillars (Megalopygidae). Consistent with this composition, the venom potently permeabilises sensory neurons and human neuroblastoma cells. This study highlights the diversity of venom composition in Limacodidae.

Proteome of urticating setae of Ochrogaster lunifer, a processionary caterpillar of medical and veterinary importance, including primary structures of putative toxins

Ochrogaster lunifer (Lepidoptera: Notodontidae) is an Australian processionary caterpillar with detachable urticating setae that have a defensive function. These true setae induce inflammation when they contact human skin, and equine foetal loss syndrome if they are accidentally ingested by gravid horses. We used transcriptomics and proteomics to identify proteins and peptides present in and on urticating setae, which may include toxins that contribute to inflammation and/or foetal loss syndromes. This process identified 37 putative toxins, including multiple homologues of the honeybee venom peptide secapin, and proteins with similarity to odorant binding proteins, arylphorins, and the insect immune modulator Diedel. This work identifies candidate molecules that may contribute to the adverse effects of processionary caterpillar setae on human and animal health.

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.

Characterization of morphological and biological aspects of venomous caterpillars of the genus Lonomia Walker (Lepidoptera: Saturniidae) in Colombia

The genus Lonomia Walker, 1855 (Lepidoptera: Saturniidae) is of particular interest to the medical community, since the scoli of these caterpillars harbor a venom that induces hemorrhaging in humans. In Colombia, deadly encounters with Lonomia achelous (Cramer, 1777), have been reported since 2000. There is little information on the main biological and ecological aspects of this genus to help better understand and develop prevention strategies. This study aimed to describe morphological and biological aspects (especially of immature stages) of four recently reported species of Lonomia in Colombia that pose a risk to humans. We collected caterpillars and adults from five localities and reared them under laboratory conditions. Specimens were identified using DNA barcoding and dissection of adult male genitalia. We provided the first description, to our knowledge, of part of the life cycles of Lonomia casanarensis Brechlin, 2017 and Lonomia orientoandensis Brechlin & Meister, 2011 and the complete life cycles of Lonomia columbiana Lemaire, 1972 and Lonomia orientocordillera Brechlin, Käch & Meister, 2013. We also present the first records of the parasitoids of L. orientocordillera, and L. casanarensis and new host plants. This information will guide not only their morphological recognition and the identification of their parasitoids and hosts, but also will guide rearing methods of these and other Lonomia species in new studies to prevent incidents with humans and create specific antivenoms.

Deadly and venomous Lonomia caterpillars are more than the two usual suspects

Caterpillars of the Neotropical genus Lonomia (Lepidoptera: Saturniidae) are responsible for some fatal envenomation of humans in South America inducing hemostatic disturbances in patients upon skin contact with the caterpillars' spines. Currently, only two species have been reported to cause hemorrhagic syndromes in humans: Lonomia achelous and Lonomia obliqua. However, species identifications have remained largely unchallenged despite improved knowledge of venom diversity and growing evidence that the taxonomy used over past decades misrepresents and underestimates species diversity. Here, we revisit the taxonomic diversity and distribution of Lonomia species using the most extensive dataset assembled to date, combining DNA barcodes, morphological comparisons, and geographical information. Considering new evidence for seven undescribed species as well as three newly proposed nomenclatural changes, our integrative approach leads to the recognition of 60 species, of which seven are known or strongly suspected to cause severe envenomation in humans. From a newly compiled synthesis of epidemiological data, we also examine the consequences of our results for understanding Lonomia envenomation risks and call for further investigations of other species' venom activities. This is required and necessary to improve alertness in areas at risk, and to define adequate treatment strategies for envenomed patients, including performing species identification and assessing the efficacy of anti-Lonomia serums against a broader diversity of species.

Biological characterization of bristle extract of Lonomia descimoni caterpillar (Lepidoptera, Saturniidae) and effectiveness of Lonomia antivenom to neutralize experimental envenomation in rats

Contact with Lonomia caterpillars can cause severe envenomation with hemorrhagic syndrome, consumptive coagulopathy, acute renal failure, and death. In Brazil, an antivenom was produced using extracts from L. obliqua caterpillar bristles as antigen and has been used in other countries in South America to treat envenomation caused by distinct species of Lonomia. This study aimed to characterize the activities of toxins from Lonomia descimoni caterpillars found in Colombia and the neutralization of these toxins by the Brazilian Lonomia antivenom. The protein composition and coagulant, phospholipase A₂, hyaluronidase, and defibrinogenating activities were evaluated and compared with the same parameters of the L. obliqua bristle extract. Immune recognition and the neutralizing ability of Lonomia antivenom were also determined. The results showed that the L. descimoni bristle extract presented marked differences in electrophoretic and mass spectrometry profiles and had coagulant, phospholipase A₂, and hyaluronidase activities significantly less intense than those of the L. obliqua extract. In rats, L. descimoni extract induced coagulopathy and hemoglobinuria when injected by intravenous or intraperitoneal routes. The Lonomia antivenom recognized the toxins in the extract of L. descimoni and reversed the experimental envenomation in rats. Our results indicate that L. descimoni caterpillars possess toxins with weaker activities than those of L. obliqua but with the potential to cause envenomation. Moreover, the Lonomia antivenom recognized and neutralized the toxins in the L. descimoni bristle extract.

Effect of Lonomia obliqua Venom on Human Neutrophils

The significant incidence of deforestation in South America culminates in the contact of humans with typical forests species. Among these species, one may highlight Lonomia obliqua caterpillar, which, when touched by humans, can poison them through their bristles. Therefore, better acknowledging the mechanisms involved in envenomation caused by Lonomia obliqua caterpillar bristle extract (LOCBE) may contribute to further treatments. Recently, we demonstrated that LOCBE induces a pro-inflammatory profile in endothelial cells; thus, we decided to investigate the effects of LOCBE on human polymorphonuclear neutrophils (PMN), which are the first leukocytes that migrate to the inflammatory focus. Our results showed that treatment with LOCBE induced PMN chemotaxis together with alterations in actin cytoskeleton and focal adhesion kinase (FAK) activation, favoring migration. Concurrently, LOCBE induced PMN adhesion to matrix proteins, such as collagen IV, fibronectin, and fibrinogen. Moreover, we observed that LOCBE attenuated PMN apoptosis and increased reactive oxygen species (ROS) production together with nuclear factor kB (NF-κB) activation—a redox-sensitive transcription factor—as well as interleukin (IL)-1β and IL-8 release. We call attention to the ROS-dependent effect of LOCBE on increased cell migration once an antioxidant treatment reverted it. In summary, we report that LOCBE activates PMN, inducing pro-inflammatory responses modulated by ROS.

Lonomia obliqua Venom Induces NF-κB Activation and a Pro-Inflammatory Profile in THP-1-Derived Macrophage

Envenomation caused by contact with Lonomia obliqua bristles is characterized by pain, an intense systemic proinflammatory reaction and disturbances in the coagulation cascade that can cause severe clinical manifestations and death. However, the role of immune system components in these effects is still poorly understood. In this study, we evaluated the cytotoxic effect of L. obliqua venom on THP-1-derived macrophages and its ability to modulate inflammatory markers, as well as the cytokine and chemokine release profile. Our results show that L. obliqua venom is able to directly exert a potent pro-inflammatory reaction in macrophages, characterized by the activation of the NF-κB transcription factor pathway, the expression of CD80 and CD83, and the release of pro-inflammatory mediators such as TNF-α, IL-1β, IL-6, IL-8 and CXCL10. These results suggest that macrophages can play an important role during the orchestration of the inflammatory response present in envenomation caused by Lonomia obliqua caterpillars.

Utilisation of compounds from venoms in drug discovery

Difficult drug targets are becoming the normal course of business in drug discovery, sometimes due to large interacting surfaces or only small differences in selectivity regions. For these, a different approach is merited: compounds lying somewhere between the small molecule and the large antibody in terms of many properties including stability, biodistribution and pharmacokinetics. Venoms have evolved over millions of years to be complex mixtures of stable molecules derived from other somatic molecules, the stability comes from the pressure to be ready for delivery at a moment's notice. Snakes, spiders, scorpions, jellyfish, wasps, fish and even mammals have evolved independent venom systems with complex mixtures in their chemical arsenal. These venom-derived molecules have been proven to be useful tools, such as for the development of antihypotensive angiotensin converting enzyme (ACE) inhibitors and have also made successful drugs such as Byetta® (Exenatide), Integrilin® (Eptifibatide) and Echistatin. Only a small percentage of the available chemical space from venoms has been investigated so far and this is growing. In a new era of biological therapeutics, venom peptides present opportunities for larger target engagement surface with greater stability than antibodies or human peptides. There are challenges for oral absorption and target engagement, but there are venom structures that overcome these and thus provide substrate for engineering novel molecules that combine all desired properties. Venom researchers are characterising new venoms, species, and functions all the time, these provide great substrate for solving the challenges presented by today's difficult targets.

Identification of Novel Toxin Genes from the Stinging Nettle Caterpillar Parasa lepida (Cramer, 1799): Insights into the Evolution of Lepidoptera Toxins

Simple Summary

Many caterpillar species can produce toxins that cause harmful reactions to humans, varying from mild irritation to death. Currently, there is very limited knowledge about caterpillar toxin diversity, because only a few species have been investigated. We used the transcriptome technique to identify candidate toxin genes from the nettle caterpillar Parasa lepida (Cramer, 1799). It is a common pest of oil palm, coconut, and mango in South and South-East Asia, which can cause severe pain and allergic responses to those in contact with them. We reported 168 candidate toxin genes. Most of them are members of the toxin genes families commonly recruited in animal venoms such as serine protease and serine protease inhibitors. However, we identified 21 novel genes encoding knottin-like peptides expressed at a high level in the transcriptome. Their predicted 3D structures are similar to neurotoxins in scorpion and tarantula. Our study suggests that P. lepida venom contains diverse toxin proteins that potentially cause allergic reactions and pain. This study sheds light on the hidden diversity of toxin proteins in caterpillar lineage, which could be future fruitful new drug sources.

Abstract

Many animal species can produce venom for defense, predation, and competition. The venom usually contains diverse peptide and protein toxins, including neurotoxins, proteolytic enzymes, protease inhibitors, and allergens. Some drugs for cancer, neurological disorders, and analgesics were developed based on animal toxin structures and functions. Several caterpillar species possess venoms that cause varying effects on humans both locally and systemically. However, toxins from only a few species have been investigated, limiting the full understanding of the Lepidoptera toxin diversity and evolution. We used the RNA-seq technique to identify toxin genes from the stinging nettle caterpillar, Parasa lepida (Cramer, 1799). We constructed a transcriptome from caterpillar urticating hairs and reported 34,968 unique transcripts. Using our toxin gene annotation pipeline, we identified 168 candidate toxin genes, including protease inhibitors, proteolytic enzymes, and allergens. The 21 P. lepida novel Knottin-like peptides, which do not show sequence similarity to any known peptide, have predicted 3D structures similar to tarantula, scorpion, and cone snail neurotoxins. We highlighted the importance of convergent evolution in the Lepidoptera toxin evolution and the possible mechanisms. This study opens a new path to understanding the hidden diversity of Lepidoptera toxins, which could be a fruitful source for developing new drugs.

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.

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.

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.

A review on Respiratory allergy caused by insects

Hypersensitivity or allergy encompasses a wide range of immunological reactions that generally have adverse consequences involving one or many organ systems of the body. Allergens are usually glycoprotein or chemically complex low molecular weight substances. The common allergens include pollen, fungal spores, house dust mite and house dust, animal danders, drugs, foods, insect emanations, and detritus, etc. Information on the role of insects in respiratory allergy is increasing in the literature. There are about 30 million living species of insects. These insects can broadly be classified as stinging insects, biting insects and non-stinging and non-biting insects. All materials form insets namely wings, scales, saliva; dried feces and venom can cause allergic diseases, such as rhinitis, conjunctivitis, asthma and urticaria. There are wide varieties of insects such as moths, butterflies, bees, wasps, hornets, yellow jackets, flies, beetles, cockroaches, and mosquitoes. Exposure to emanations and detritus of these insects may lead to several allergies in some genetically predisposed individuals. Therefore, it is of interest to review allergies caused by various insect's stings and bites and their adverse effect on the human body.

Arthropod venoms: Biochemistry, ecology and evolution

Comprising of over a million described species of highly diverse invertebrates, Arthropoda is amongst the most successful animal lineages to have colonized aerial, terrestrial, and aquatic domains. Venom, one of the many fascinating traits to have evolved in various members of this phylum, has underpinned their adaptation to diverse habitats. Over millions of years of evolution, arthropods have evolved ingenious ways of delivering venom in their targets for self-defence and predation. The morphological diversity of venom delivery apparatus in arthropods is astounding, and includes extensively modified pedipalps, tail (telson), mouth parts (hypostome), fangs, appendages (maxillulae), proboscis, ovipositor (stinger), and hair (urticating bristles). Recent investigations have also unravelled an astonishing venom biocomplexity with molecular scaffolds being recruited from a multitude of protein families. Venoms are a remarkable bioresource for discovering lead compounds in targeted therapeutics. Several components with prospective applications in the development of advanced lifesaving drugs and environment friendly bio-insecticides have been discovered from arthropod venoms. Despite these fascinating features, the composition, bioactivity, and molecular evolution of venom in several arthropod lineages remains largely understudied. This review highlights the prevalence of venom, its mode of toxic action, and the evolutionary dynamics of venom in Arthropoda, the most speciose phylum in the animal kingdom.

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.

Effectiveness of Lonomia antivenom in recovery from the coagulopathy induced by Lonomia orientoandensis and Lonomia casanarensis caterpillars in rats

In South America, accidental contact with Lepidoptera larvae can produce a diversity of reactions that vary from dermatological problems to severe hemorrhagic syndromes, such as those caused by contact with caterpillars of the genus Lonomia (Saturniidae). Lonomia venom can alter the hemostatic system and lead to renal failure, internal and brain bleeding, and in severe cases, death. The only specific treatment available for these envenomations is the Lonomia Antivenom (LAV) produced by the Butantan Institute, in Brazil, using an extract of Lonomia obliqua scoli as the antigen. LAV has been used to treat exposure to other Lonomia species across South America. However, no experimental studies have been performed to test the efficacy of LAV in neutralizing the venom of species other than L. obliqua found in Southern Brazil. In this study, we tested the effectiveness of LAV in reversing the hemostatic disturbances induced by injecting Lonomia casanarensis (Lca) and Lonomia orientoandensis (Lor) scolus extracts into rats and compared the effects to the case of L. obliqua (Lob) scolus extract-induced envenomation. Lca and Lor caterpillars were collected in Colombia, and some of them were reared to adults for identification. The Minimum Defibrinating Doses (MDD) of Lca and Lor were estimated. Rats were injected (i.d.) with a dose of 3 MDD per rat of each scolus extract and treated (i.v.) with 1.5 mL of LAV or 1.5 mL of saline. Twenty-four hours after the treatment, the fibrinogen levels and platelet counts had recovered to the hemostatic levels in the groups treated with LAV. The groups treated with the saline solution had fibrinogen levels and platelet counts at non-hemostatic levels. Thromboelastometric analyses confirmed these results. In conclusion, the results showed that LAV is effective at neutralizing the envenomation induced by Lca and Lor spine extracts in rats and restoring hemostasis.

Effects of Lonomia obliqua Venom on Vascular Smooth Muscle Cells: Contribution of NADPH Oxidase-Derived Reactive Oxygen Species

Envenomation caused by human contact with the caterpillar Lonomia is characterized by deleterious effects on coagulation and patency of blood vessels. The cellular effects induced by Lonomia obliqua venom highlights its capacity to activate endothelial cells, leading to a proinflammatory phenotype. Having more knowledge about the mechanisms involved in envenomation may contribute to better treatment. We aimed to evaluate the effects of Lonomia obliqua caterpillar bristle extract (LOCBE) on vascular smooth muscle cells (VSMC). We observed that LOCBE induced VSMC migration, which was preceded by alterations in actin cytoskeleton dynamics and Focal Adhesion Kinase activation. LOCBE also induced Extracellular Signal-Regulated Kinase (ERK) phosphorylation in VSMC, and the inhibition of this pathway impaired cell proliferation. Stimulation of VSMC with LOCBE triggered reactive oxygen species (ROS) production through the activation of NADPH oxidase. The rapid increase in these ROS further induced mitochondrial ROS production, however only NADPH oxidase-derived ROS were involved in ERK activation in VSMC. We that demonstrated the chemotactic and proliferative effects of LOCBE on VSMC were dependent on ROS production, mainly through NADPH oxidase. Together, the data show that Lonomia obliqua venom can interact with and activate VSMC. These effects rely on ROS production, suggesting new potential targets for treatment against vascular damage during envenomation.

Hemostatic disorders induced by skin contact with Lonomia obliqua (Lepidoptera, Saturniidae) caterpillars

Patients envenomed by Lonomia sp caterpillars initially experience a mild burning pain, headache, nausea, vomiting, and skin and mucosal hemorrhages. Some patients can rapidly progress to a severe coagulopathy that presents as visceral or intracerebral hemorrhaging. We studied the hemostatic alterations that occurred in 14 patients who were envenomed by Lonomia obliqua in Southern Brazil and presented at the Hospital São Vicente de Paulo (Passo Fundo, RS), Brazil during the summers of 1993 and 1994 when Lonomia antivenom was not yet available for treatment. The patients were classified into to 4 clinical groups: 0 (two patients), I (eight patients), II (two patients), and III (two patients). The patients were admitted to the hospital between 4 hours and five days after contact with the caterpillars. In this study, the coagulation parameters of the patients were followed up for up to 172 hours after the accidents. The patients received no treatment with the exceptions of two patients who received blood transfusions and antifibrinolytic treatment. The observed abnormalities related to blood coagulation and fibrinolytic factors were similar regardless of the severity of the bleeding symptoms. These findings suggest that alterations in hemostatic parameters without thrombocytopenia are not predictors of the seriousness of such accidents. Thus, consumptive disorder and reactive fibrinolysis are not proportional to mild coagulopathy. Furthermore, these patients recovered. The hemostatic parameters of most of the patients normalized between 96 and 120 h after the accident.

Protein content of the Hylesia metabus egg nest setae (Cramer [1775]) (Lepidoptera: Saturniidae) and its association with the parental investment for the reproductive success and lepidopterism

Hylesia metabus is a neotropical moth possessing toxic setae, which once in contact with the skin cause a severe dermatitis to humans known as lepidopterism. The only known function of the setae in the life cycle is to provide protection during the mating and egg-hatching stages. Approximately 65% of the protein content of the setae is a cluster of five proteases (28-45kDa) showing sequence homology to other S1A serine proteases. The N-glycans of a 40kDa protease are a mixture of neutral and sulfated G0F structures. The sulfated N-glycans have an important role in triggering the inflammatory response typical of lepidopterism while the proteolytic activity may promote the erosion of blood vessels and tissues causing focal hemorrhages. The presence of Chitinase and a 30kDa lipoprotein is probably related to the antifungal defense. In addition, chitin digestion of the setae may potentiate the inflammatory reaction caused by the toxins due to the formation of chitin adjuvants fragments. The combined effect of proteases and a chitinase may dissuade predating arthropods, by damaging their exoskeletons. Vitellogenin, a bacteriostatic protein, is able to recognize pathogen-associated patterns, which suggests its possible role in protecting the embryonated eggs from pathogenic microorganisms.

SIGNIFICANCE

The present study is the first report describing the different protein species present in the urticating egg nest setae of the neotropical moth Hylesia metabus - the most harmful of the Hylesia moths - causing a severe urticating dermatitis in humans known as lepidopterism. A distinctive feature of the venom is the presence of five different S1A serine proteases probably used to guarantee a more efficient degradation of a wider number of protein substrates. This work confirms that the presence of sulfated N-glycans is not an isolated finding since its presence has been demonstrated in two different proteases affirming that this PTM is of importance for the activation of the inflammatory response typical of lepidopterism. Additionally, this study gives useful information on the defense mechanisms used for protection of its progeny vs. vertebrate predators, fungus, bacteria or other arthropods such as ants. The proteins detected in the egg nest should be seen as an extended parental effort made by the females in order to achieve an optimal reproductive success, thus compensating for the considerable loss of progeny during the larval stages that seriously limits the number of sexually mature adults reaching the reproductive phase.

The complete genome of a baculovirus isolated from an insect of medical interest: Lonomia obliqua (Lepidoptera: Saturniidae)

Lonomia obliqua (Lepidoptera: Saturniidae) is a species of medical importance due to the severity of reactions caused by accidental contact with the caterpillar bristles. Several natural pathogens have been identified in L. obliqua, and among them the baculovirus Lonomia obliqua multiple nucleopolyhedrovirus (LoobMNPV). The complete genome of LoobMNPV was sequenced and shown to have 120,022 bp long with 134 putative open reading frames (ORFs). Phylogenetic analysis of the LoobMNPV genome showed that it belongs to Alphabaculovirus group I (lepidopteran-infective NPV). A total of 12 unique ORFs were identified with no homologs in other sequenced baculovirus genomes. One of these, the predicted protein encoded by loob035, showed significant identity to an eukaryotic transcription terminator factor (TTF2) from the Lepidoptera Danaus plexippus, suggesting an independent acquisition through horizontal gene transfer. Homologs of cathepsin and chitinase genes, which are involved in host integument liquefaction and viral spread, were not found in this genome. As L. obliqua presents a gregarious behavior during the larvae stage the impact of this deletion might be neglectable.

Population Explosions of Tiger Moth Lead to Lepidopterism Mimicking Infectious Fever Outbreaks

Lepidopterism is a disease caused by the urticating scales and toxic fluids of adult moths, butterflies or its caterpillars. The resulting cutaneous eruptions and systemic problems progress to clinical complications sometimes leading to death. High incidence of fever epidemics were associated with massive outbreaks of tiger moth Asota caricae adult populations during monsoon in Kerala, India. A significant number of monsoon related fever characteristic to lepidopterism was erroneously treated as infectious fevers due to lookalike symptoms. To diagnose tiger moth lepidopterism, we conducted immunoblots for tiger moth specific IgE in fever patients' sera. We selected a cohort of patients (n = 155) with hallmark symptoms of infectious fevers but were tested negative to infectious fevers. In these cases, the total IgE was elevated and was detected positive (78.6%) for tiger moth specific IgE allergens. Chemical characterization of caterpillar and adult moth fluids was performed by HPLC and GC-MS analysis and structural identification of moth scales was performed by SEM analysis. The body fluids and chitinous scales were found to be highly toxic and inflammatory in nature. To replicate the disease in experimental model, wistar rats were exposed to live tiger moths in a dose dependant manner and observed similar clinico-pathological complications reported during the fever epidemics. Further, to link larval abundance and fever epidemics we conducted cointegration test for the period 2009 to 2012 and physical presence of the tiger moths were found to be cointegrated with fever epidemics. In conclusion, our experiments demonstrate that inhalation of aerosols containing tiger moth fluids, scales and hairs cause systemic reactions that can be fatal to human. All these evidences points to the possible involvement of tiger moth disease as a major cause to the massive and fatal fever epidemics observed in Kerala.

Accident involving a 2-year-old child and Lonomia obliqua venom: clinical and coagulation abnormalities

Poisons of caterpillars have different effects on inflammatory and coagulation systems. This is a case report of a 2-year-old child that accidentally came in contact with several caterpillars of the species Lonomia obliqua. At first, the patient's exams presented abnormal coagulation and decreased fibrinogen, but the patient did not evolve to active bleeding or acute renal failure. The patient received antilonomic serum 15 h after the accident and the treatment was repeated after another 12 h due to persistent alterations shown by the coagulation exams. The venom of L. obliqua has several substances that act on the coagulation and inflammatory systems. The event is characterized by a hemorrhagic syndrome with decreases in fibrinogen. L. obliqua Stuart-factor activator (Losac) and L. obliqua prothrombin activator protease (Lopap) are components that act with procoagulatory effects. The pro-inflammatory action occurs due to metalloproteases, hyaluronidases and other substances with inflammatory activity. Studies on caterpillar venom can give new perspectives on the treatment of cancer and other diseases that cause dysfunction of the extra-cellular matrix.

[2013 update about arthropod envenomations in French Guyana]

French Guiana, by its geographical situation, its climate and its biodiversity, is often called "the green hell". Indeed, this French department of America shelters a wildlife rich, abundant among which many species of arthropods, some of which are responsible for envenomations. These accidents consist of scorpion's or hymenoptera's stings or spider's bites. The associated clinical aspect is variable, from simple pain to circulatory collapse, or lung oedema. However, symptomatology is generally mild; four deaths associated to arthropod envenomations have been reported in the past 25 years. This article focuses on envenomations in French Guiana, describing favoring human behavior, risks and venoms associated with the main related animal species.

Venom gland extract is not required for successful parasitism in the polydnavirus-associated endoparasitoid Hyposoter didymator (Hym. Ichneumonidae) despite the presence of numerous novel and conserved venom proteins

The venom gland is a conserved organ in Hymenoptera that shows adaptations associated with life-style diversification. Few studies have investigated venom components and function in the highly diverse parasitic wasps and all suggest that the venom regulates host physiology. We explored the venom of the endoparasitoid Hyposoter didymator (Campopleginae), a species with an associated polydnavirus produced in the ovarian tissue. We investigated the effects of the H. didymator venom on two physiological traits of the host Spodoptera frugiperda (Noctuidae): encapsulation response and growth rate. We found that H. didymator venom had no significant effect on host cellular immunity or development, suggesting that it does not contribute to parasitism success. The host physiology seemed to be modified essentially by the ovarian fluid containing the symbiotic polydnaviruses. Proteomic analyses indicated that the H. didymator venom gland produces a large variety of proteins, consistent with the classical hymenopteran venom protein signature, including: reprolysin-like, dipeptidyl peptidase IV, hyaluronidase, arginine kinase or allergen proteins. The venom extracts also contained novel proteins, encoded by venom genes conserved in Campopleginae ichneumonids, and proteins with similarities to active molecules identified in other parasitoid species, such as calreticulin, reprolysin, superoxide dismutase and serpin. However, some of these proteins appear to be produced only in small amounts or to not be secreted. Possibly, in Campopleginae carrying polydnaviruses, the host-modifying activities of venom became redundant following the acquisition of polydnaviruses by the lineage.

A pro-inflammatory profile of endothelial cell in Lonomia obliqua envenomation

Lonomia obliqua envenomation is characterized by intense local inflammatory reaction, which, dependent on the severity of the case, is followed by severe clinical manifestations related to hemorrhagic disorders that can lead to fatal outcome. These effects were imputed to several toxins present in L. obliqua venom, which are responsible for procoagulant, anticoagulant as well as antithrombotic activities, being also able to interfere with vascular cells functions. In this work, the intravital microscopy analysis show that after administration of low doses of L. obliqua venom (1-3 μg/ml) on hamster cheek pouch, there was no alterations neither on arterioles or venules caliber nor in the vascular permeability up to 30 min. However, after 10 min in contact with venom occurred a clear activation in the vascular bed, characterized by an increase in leukocyte rolling and adhesion on endothelium of hamster cheek pouch venules. A confocal analysis of vascular beds, confirmed these results showing an increase in endothelial E-selectin and VCAM-1 expression. The effects of L. obliqua venom on human endothelial cell (EC) in vitro were also investigated. The treatment of EC with venom (1-3 μg/ml) did not affect cell viability. However, at concentrations as low as 3 μg/ml of L. obliqua venom modifies actin cytoskeleton dynamics, and increases focal adhesion contacts, inducing stress fiber formation, focal adhesion kinase (FAK) phosphorylation and its subsequent association to actin. These effects are followed by the activation of NF-κB pathway, a critical signaling in several events associated to vascular inflammation. Accordingly, L. obliqua venom leads to a significant increase in COX-2, NOS-2, HO-1, MMP-2 and MMP-9 expression. Taken together the data show that, even at low concentrations, L. obliqua venom can activate endothelial cells, which assume a pro-inflammatory profile, contributing for local effects and probably also for systemic disturbances due to its ability to modulate the properties of the vascular system.

The effects of Lonomin V, a toxin from the caterpillar (Lonomia achelous), on hemostasis parameters as measured by platelet function

Platelets play a central role in hemostasis during vascular injury. Patients affected with the hemorrhagic syndrome caused by contact with Lonomia achelous caterpillars (Lac) Lepidoptera distributed in various South American countries, show digestive, pulmonary and intraperitoneal bleeding in combination with hematomas and echymosis. In the present study, we have evaluated the effects of Lonomin V (serine protease isolated from Lac hemolymph) on some functional properties of platelets, evaluating its importance in primary hemostasis. Platelet adhesion to fibrinogen was reduced by 19, 20, 36, and 37% after pre-treated with 0.2, 2, 20 and 40 nM of Lonomin V, respectively. Pre-incubation of the platelets with 408 nM of Lonomin V, for 4 min at 37 °C, resulted in complete inhibition of the collagen-induced platelet aggregation, in contrast to 56% inhibition of the ADP - induced platelet aggregation. Lonomin V also inhibited anti-α(IIb)β(3) integrin binding to platelets by 56, 57, 52 and 54% at concentrations of 0.2, 2, 20 and 40 nM respectively. Additionally, Lonomin V inhibited anti-P-selectin binding to platelets by 28, 37, 33 and 33% at the same concentrations. The platelets tested with Lonomin V did not modify their viability. In summary, Lonomin V inhibited platelet aggregation, probably caused by the degradation of collagen. The anti-platelet activity of Lonomin V has been shown to be unique and a potentially useful tool for investigating cell-matrix and cell-cell interactions and for the development of antithrombotic agents in terms of their anti-adhesive activities.

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.

Antilonomic Effects of Brazilian Brown Seaweed Extracts

The aim of this work was to investigate the hemolysis and blood clotting activity of Lomonia obliqua venom and the ability of some Brazilian marine algal extracts ( Canistrocarpus cervicornis, Stypopodium zonale and Dictyota pfaffi) to antagonize such biological activities. L. obliqua caterpillars are dangerous to human beings and envenomation symptoms are characterized by hemorrhagic, hemolytic and blood clotting disorders, and acute renal failure, which sometimes lead to the death of the victims. Through in vitro experiments we have shown that L. obliqua venom is able to clot human plasma and hemolize human erythrocytes and that the coagulation activity of the venom is inhibited by the extracts of C. cervicornis, S. zonale and D. pfaffi. In contrast, C. cervicornis and S. zonale extracts did not inhibit the hemolytic activity of L. oblqua, as did the extract of D. pfaffi. These finding indicate that marine algae may be used as antivenoms or may contribute to the development of compounds with antilonomic effects.

Efficacy of serum therapy on the treatment of rats experimentally envenomed by bristle extract of the caterpillar Lonomia obliqua: Comparison with epsilon-aminocaproic acid therapy

Large number of accidents caused by contact with Lonomia obliqua caterpillars, with hemorrhagic complications, have occurred in southern Brazil. Based on Venezuelan expertise to treat Lonomia achelous envenomation, the use of the antifibrinolytic drug epsilon-aminocaproic acid (EACA) has been indicated to treat L. obliqua envenomation, although no evidence has been presented to justify its use. Specific antivenom (antilonomic serum (ALS)) that neutralizes toxins that cause envenomation was developed. To compare the effectiveness of such treatments, rats were injected i.d. with the bristle extract of L. obliqua caterpillars and treated 15 min, 1 and 6 h after with saline, ALS, EACA, or with both ALS and EACA. ALS elicited fibrinogen recovery and normalization of thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (APTT), independent of when it was administered; however, hematocrit was decreased in the group treated later. Saline or EACA-treated groups presented neither fibrinogen recovery nor normalization of hemostatic parameters. A high death rate was observed in the group treated with EACA 15 min after the envenomation. Prolongation of TT and APTT observed in the group treated with EACA and ALS indicated that this association gave no benefit in relation to the group treated solely with ALS. The results presented herein suggest that ALS is the only effective treatment for envenomation caused by contact with Lonomia obliqua caterpillars and indicate that EACA should not be administered in the initial phase of envenomation.