Centipede envenomation

Clinical characteristics, management, outcome, and cost of stings and bites in patients admitted to a tertiary care teaching hospital

AIM

The objective of this study was to identify the clinical epidemiology and medical cost of stings and bites at a tertiary care hospital in South India.

SUBJECTS AND METHODS

The medical records of hospitalized patients in the tertiary care unit between 2016 and 2020 with the history of either being stung or bitten by insects were reviewed retrospectively. The patient's demographic details, clinical symptoms, treatment chart, expenditure details, and outcomes were collected in pre-structured case report forms. The data were analyzed using SPSS Version 20.0.

RESULTS

A total of 66 patients were enrolled, with a mean age of 45.86 ± 23.37 years. The majority of the incidence was due to bee stings (61%). Anaphylaxis was reported in 38% of the cases, followed by acute kidney injury (10.6%). The cost of hospitalization was found to be higher for spider bites at 896.73 ± 1414.95 USD, followed by wasp stings at 989.81 ± 1185.57 USD. In patients with complications, the average cost of stings and bites was 438.81 ± 685.81 USD. Most of the patients received antibiotics (75.8%), followed by steroids (62.1%).

CONCLUSION

Stings and bite injuries may appear harmless initially, but they can cause severe complications in unidentified cases and for those who do not seek urgent medical attention. Antibiotics and corticosteroids can help in the management of envenomation.

Ultrasound-Guided Superficial Radial Nerve Block in the Emergency Department for Pain Management following Centipede Bite

Centipede bites are reported in many parts of tropical and subtropical countries, such as India. Centipede envenomation produces significant local symptoms, with pain being the most prominent symptom. The emergency department (ED) plays a crucial role in managing the victims through appropriate pain management and control of other local and systemic symptoms. Nonopioids and weak opioids, along with local measures, are often employed, but the intense pain is often refractory to these conventional techniques. Regional anesthesia has numerous benefits over these traditional measures, such as avoidance of polypharmacy and its consequent systemic adverse effects, excellent quality of pain control, and decreased need or avoidance of hospital admission. The applications of regional anesthesia have recently increased tremendously in the ED but are unreported for the management related to centipede bites. We report a case of centipede bite in which conventional analgesics did not help, and the pain was successfully managed by low-volume selective sensory peripheral nerve block.

Centipede envenomation (Chilopoda): Case report

Centipedes are venomous arthropods that have an elongated body, divided into many segments, presenting a pair of legs in each segment, adapted pairs of paws that simulate fangs and inject venom causing intense pain, with local erythema and edema, and rarely, blisters and skin necrosis. We present the case of a young woman pricked on her upper lip with intense swelling and local pain and discuss the real danger of envenomation and the therapeutic measures that should be taken.

Isolation and characterization of the major centipede allergen Sco m 5 from Scolopendra subspinipes mutilans

BACKGROUND

Allergic reactions have been observed following both direct centipede bites and the clinical use of centipede-containing medicines, such as traditional Chinese medicines utilizing Scolopendra subspinipes mutilans; however, no natural centipede allergen has yet been characterized.

METHODS

An allergen was purified from S. s. mutilans venom using Superdex 75 gel filtration and RESOURCE S ion chromatography, and its primary structure was determined via a combination of LC-MS-MS, MALDI-TOF/TOF and protein sequencing techniques. Its potential allergenicity was evaluated by immunoblotting, ELISAs, skin prick tests (SPTs) and mast cell activation assays.

RESULTS

A novel allergen Sco m 5 (210 amino acids long) was successfully purified from crude S. s. mutilans venom. Sco m 5 could promote the degranulation of a human mast cell line, HMC-1. Among centipede-allergic patients, Sco m 5 showed an 83.3% IgE-binding frequency and a 66.7% positive reaction frequency, as detected by immunoblotting and SPTs, respectively. Sco m 5 IgE-binding frequencies of common Chinese population was found to be 9%-16%. Sera positive for Sco m 5 IgE-binding was cross-reactive against venom from the wasp Vespa mandaeinia.

CONCLUSIONS

The present study isolated and characterized a novel allergen termed as Sco m 5 from the centipede S. s. mutilans. The use of Sco m 5 to identify centipede-allergic individuals could be important, given the high potential allergenicity of Sco m 5 among the general Chinese population, along with the likely possibility of cross-reactivity against wasp venom among centipede-allergic patients.

An unusual two-stage infection following a scolopendra bite

Background:

Scolopendrae represent the best-known genus of centipedes. They are nocturnal general feeders with strong mandibles and venomous fangs which leave visible puncture marks at the bite site. The bite accidents occur during the warm rainy season and mostly take place on the extremities. Following the bite, the most common symptoms are mild: limited localized erythema, pain, swelling, local itching and burning sensation. However, more severe local and systemic sequelae can not be excluded.

Method:

we report the case of a 63-year-old man with fever and a widespread edema of the right hand and forearm, happened as a consequence of a Scolopendra Subspinipes bite. During the weeks following the bite, he developed a severe unusual superinfection via hematogenous dissemination, which required a double surgical debridement and a targeted intravenous antibiotic therapy.

Results:

the complete clinical recovery took over two months.

Conclusions:

Many victims of Scolopendra envenomation do not seek medical attention since most symptoms will resolve spontaneously. The case presented falls within the spectrum of those rare cases which escalate due to bacterial superinfection.

Biologically active metabolite(s) from haemolymph of red-headed centipede Scolopendra subspinipes possess broad spectrum antibacterial activity

The discovery of novel antimicrobials from animal species under pollution is an area untapped. Chinese red-headed centipede is one of the hardiest arthropod species commonly known for its therapeutic value in traditional Chinese medicine. Here we determined the antibacterial activity of haemolymph and tissue extracts of red-headed centipede, Scolopendra subspinipes against a panel of Gram-positive and Gram-negative bacteria. Lysates exhibited potent antibacterial activities against a broad range of bacteria tested. Chemical characterization of biologically active molecules was determined via liquid chromatography mass spectrometric analysis. From crude haemolymph extract, 12 compounds were identified including: (1) L-Homotyrosine, (2) 8-Acetoxy-4-acoren-3-one, (3) N-Undecylbenzenesulfonic acid, (4) 2-Dodecylbenzenesulfonic acid, (5) 3H-1,2-Dithiole-3-thione, (6) Acetylenedicarboxylate, (7) Albuterol, (8) Tetradecylamine, (9) Curcumenol, (10) 3-Butylidene-7-hydroxyphthalide, (11) Oleoyl Ethanolamide and (12) Docosanedioic acid. Antimicrobial activities of the identified compounds were reported against Gram-positive and Gram-negative bacteria, fungi, viruses and parasites, that possibly explain centipede's survival in harsh and polluted environments. Further research in characterization, molecular mechanism of action and in vivo testing of active molecules is needed for the development of novel antibacterials.

Clinico-epidemiology of arthropod stings and bites in primary hospitals of North Western province of Sri Lanka

OBJECTIVE

Arthropod stinging and bites are common environmental hazards in Sri Lanka. However, their medical importance has not been fully evaluated yet. This study aims to study the burden, epidemiology, and outcome of stings and bites in primary hospitals in the Kurunegala district in North Western Province (NWP) of Sri Lanka.

METHODOLOGY

The study was conducted one year from 25th May 2013 to 25th May 2014. Details of all stings and bites admissions and their outcomes were retrospectively extracted from hospital records in all 44 primary hospitals in the district.

RESULTS

There were 623 stings and bites with population incidence of 38/100,000 (95% CI 27-52). There were no deaths. Median age was 38 years (IQR: 19-53 years), and 351 (56%) were males. Most of stings and bites (75%) occurred in the daytime. Median time to hospital arrival was 55 minutes (IQR: 30 min to 2 h). The offending arthropods had been identified in 557 (89%) cases, of them, 357 (57%) were Hymenoptera (hornet and bees), 99 centipedes, 61 spiders and 40 scorpions. Local pain occurred in 346 (56%) cases - centipede 69 (70%), Scorpion 24 (60%), spider 36 (59%), Hymenoptera 187 (52%) and unidentified 30 (45%). Hymenoptera stings and spider bites occurred between 06 am to 12 noon, and scorpion stings and centipede bites mostly occurred between 06 pm to 12 midnight. Mild, moderate to severe anaphylaxis reactions occurred in 173 (28%) patients including 110 Hymenoptera stings - mild 39, moderate 62 and severe 9. From primary hospitals, 53(9%) cases had been transferred to tertiary care units for further management. Of them, 41 cases were Hymenoptera stings and 24 (58%) of them had mild, moderate to severe anaphylaxis. In the entire group, 27% severe cases received adrenaline.

CONCLUSIONS

The primary hospitals in NW province of Sri Lanka manage large numbers of arthropod stings and bites. These include Hymenoptera (hornet and bee), centipedes, spiders, and scorpions. Pain, swellings and anaphylactic reactions were the most common adverse effects.

Lymphangitis From Scolopendra heros Envenomation: The Texas Redheaded Centipede

Envenomation by Scolopendra heros, the Texas redheaded centipede, can present variably. Although transient pain and erythema are often treated conservatively, complications may include cellulitis, necrosis, myocardial infarction, and rhabdomyolysis. We present a case of an elderly man who came to the emergency department with lymphangitis and dermatitis secondary to a centipede sting that awoke him from sleep. It is important to recognize the potential of centipede envenomation to have severe local and systemic manifestations.

Clinical consequences of centipede bite: Is it neurotoxic?

The primary purpose of this article was to review the current literature regarding the clinical consequences of centipede envenomation in humans, in order to determine whether the bite of these arthropods is neurotoxic to humans or not. A thorough search of the literature regarding the clinical consequences of centipede bites in humans was applied, with great respect to neurological symptoms potentially caused by such bites. Centipede bite commonly causes only local reactions, which usually resolve within a few days without sequelae. The patients in the majority of centipede envenomations describe a painful but benign syndrome. However, mild constitutional symptoms are relatively frequent. Remarkably, centipedes can rarely cause severe systematic reactions such as anaphylaxis or even hypotension and myocardial ischemia. Factors such as patient age, comorbidity, anatomic site of envenomation, and size/species of centipede should be considered when evaluating a centipede envenomation victim. According to the current literature, the centipede bite does not seem to be neurotoxic to humans. However, it commonly causes symptoms mediated by the nervous system. These include local and generalized symptoms, with the first dominated by sensory disturbances and the second by non-specific symptoms such as headache, anxiety and presyncope. Based on our results, the answer to our study’s question is negative. The centipede bite is not neurotoxic to humans. However, it commonly causes symptoms mediated by the nervous system, which include primarily local pain and sensory disturbances, as well as generalized non-specific symptoms such as headache, anxiety and vagotonia.

A pain-inducing centipede toxin targets the heat activation machinery of nociceptor TRPV1

The capsaicin receptor TRPV1 ion channel is a polymodal nociceptor that responds to heat with exquisite sensitivity through an unknown mechanism. Here we report the identification of a novel toxin, RhTx, from the venom of the Chinese red-headed centipede that potently activates TRPV1 to produce excruciating pain. RhTx is a 27-amino-acid small peptide that forms a compact polarized molecule with very rapid binding kinetics and high affinity for TRPV1. We show that RhTx targets the channel's heat activation machinery to cause powerful heat activation at body temperature. The RhTx-TRPV1 interaction is mediated by the toxin's highly charged C terminus, which associates tightly to the charge-rich outer pore region of the channel where it can directly interact with the pore helix and turret. These findings demonstrate that RhTx binding to the outer pore can induce TRPV1 heat activation, therefore providing crucial new structural information on the heat activation machinery.

The risky business of being an entomologist: A systematic review

BACKGROUND

Adverse work-related health outcomes are a significant problem worldwide. Entomologists, including arthropod breeders, are a unique occupational group exposed to potentially harmful arthropods, pesticides, and other more generic hazards. These exposures may place them at risk of a range of adverse work-related health outcomes.

OBJECTIVES

To determine what adverse work-related health outcomes entomologists have experienced, the incidence/prevalence of these outcomes, and what occupational management strategies have been employed by entomologists, and their effectiveness.

METHODS

A systematic search of eight databases was undertaken to identify studies informing the review objectives. Data pertaining to country, year, design, work-exposure, adverse work-related health outcomes, incidence/prevalence of these outcomes, and occupational management strategies were extracted, and reported descriptively.

DISCUSSION

Results showed entomologists experienced work-related allergies, venom reactions, infections, infestations and delusional parasitosis. These related to exposure to insects, arachnids, chilopods and entognathans, and non-arthropod exposures, e.g. arthropod feed. Few studies reported the incidence/prevalence of such conditions, or work-related management strategies utilised by entomologists. There were no studies that specifically investigated the effectiveness of potential management strategies for entomologists as a population. Indeed, critical appraisal analysis indicated poor research quality in this area, which is a significant research gap.

CONCLUSIONS

Entomologists are a diverse, unique occupational group, at risk of a range of adverse work-related health outcomes. This study represents the first systematic review of their work-related health risks. Future studies investigating the prevalence of adverse work-related health outcomes for entomologists, and the effectiveness of management strategies are warranted to decrease the disease burden of this otherwise understudied group.

Cardiovascular collapse after myocardial infarction due to centipede bite

Centipede bites have been reported to cause localized and/or systemic symptoms including local pain, erythema and edema, nausea and vomiting, palpitations, headache, lymphadenopathy, and rhabdomyolysis. However, acute myocardial infarction due to centipede envenomation is reported in only three cases in English medical literature.We present a case of 31-year-old male bitten by a golden colored centipede leading to myocardial infarction and cardiopulmonary arrest which is seen very rarely. The patient was admitted to emergency department with a swollen and painful right foot. However, typical chest pain became the major complaint and cardiopulmonary arrest developed while electrocardiography was being obtained. The patient was resuscitated successfully for 5 min and acute infero-posterolateral myocardial infarction was detected on electrocardiography.

Venom regeneration in the centipede Scolopendra polymorpha: evidence for asynchronous venom component synthesis

Venom regeneration comprises a vital process in animals that rely on venom for prey capture and defense. Venom regeneration in scolopendromorph centipedes likely influences their ability to subdue prey and defend themselves, and may influence the quantity and quality of venom extracted by researchers investigating the venom's biochemistry. We investigated venom volume and total protein regeneration during the 14-day period subsequent to venom extraction in the North American centipede Scolopendra polymorpha. We further tested the hypothesis that venom protein components, separated by reversed-phase fast protein liquid chromatography (RP-FPLC), undergo asynchronous (non-parallel) synthesis. During the first 48 h, volume and protein mass increased linearly. Protein regeneration lagged behind volume regeneration, with 65–86% of venom volume and 29–47% of protein mass regenerated during the first 2 days. No additional regeneration occurred over the subsequent 12 days, and neither volume nor protein mass reached initial levels 7 months later (93% and 76%, respectively). Centipede body length was negatively associated with rate of venom regeneration. Analysis of chromatograms of individual venom samples revealed that 5 of 10 chromatographic regions and 12 of 28 peaks demonstrated changes in percent of total peak area (i.e., percent of total protein) among milking intervals, indicating that venom proteins are regenerated asynchronously. Moreover, specimens from Arizona and California differed in relative amounts of some venom components. The considerable regeneration of venom occurring within the first 48 h, despite the reduced protein content, suggests that predatory and defensive capacities are minimally constrained by the timing of venom replacement.

Centipede venom: recent discoveries and current state of knowledge

Centipedes are among the oldest extant venomous predators on the planet. Armed with a pair of modified, venom-bearing limbs, they are an important group of predatory arthropods and are infamous for their ability to deliver painful stings. Despite this, very little is known about centipede venom and its composition. Advances in analytical tools, however, have recently provided the first detailed insights into the composition and evolution of centipede venoms. This has revealed that centipede venom proteins are highly diverse, with 61 phylogenetically distinct venom protein and peptide families. A number of these have been convergently recruited into the venoms of other animals, providing valuable information on potential underlying causes of the occasionally serious complications arising from human centipede envenomations. However, the majority of venom protein and peptide families bear no resemblance to any characterised protein or peptide family, highlighting the novelty of centipede venoms. This review highlights recent discoveries and summarises the current state of knowledge on the fascinating venom system of centipedes.

Peptidomics combined with cDNA library unravel the diversity of centipede venom

Centipedes are one of the oldest venomous arthropods using toxin as their weapon to capture prey. But little attention was focused on them and only few centipede toxins were demonstrated with activity on ion channels. Therefore, more deep works are needed to understand the diversity of centipede venom. In the present study, we use peptidomics combined with cDNA library to uncover the diversity of centipede Scolopendra subspinipes mutilans L. Koch. 192 peptides were identified by LC-MS/MS and 79 precursors were deduced by cDNA library. Surprisingly, the signal peptides of centipede toxins were more complicated than any other animal toxins and even exhibited large differences in homologues. Meanwhile, a large number of variants generated by alternative cleavage sites were detected by mass spectra. Odd number of cystein (3, 5, 7) found in the mature peptides were seldom seen in peptide toxins. In additional, two novel cysteine frameworks (C-C-C-CCC, C-C-C-C-CC-CC) were identified from 16 different cysteine frameworks from centipede peptides. Only 29 precursors have clear targets, while others may provide a potential diversity function for centipede. These findings highlight the extensive diversity of centipede toxins and provide powerful tools to understand the capture and defense weapon of centipede.

BIOLOGICAL SIGNIFICANCE

Peptide toxins from venomous animal have attracted increasing attentions due to their extraordinary chemical and pharmacological diversity. Centipedes are one of the most used Chinese traditional medicines, but little was known about the active components. The venom of Scolopendra subspinipes mutilans L. Koch is first deeply analyzed in this work and most of peptides were never discovered before. Interestingly, the number and arrangement of cysteine showed a larger different to known peptide toxins such spider or scorpion toxins. Moreover, only 29 peptides from this centipede venom were identified with known function. It suggested that our work not only important to understand the composition of centipede venom, but also provide many valuable peptides for potential biological functions.

Variation in venom yield and protein concentration of the centipedes Scolopendra polymorpha and Scolopendra subspinipes

Venom generally comprises a complex mixture of compounds representing a non-trivial metabolic expense. Accordingly, natural selection should fine-tune the amount of venom carried within an animal's venom gland(s). The venom supply of scolopendromorph centipedes likely influences their venom use and has implications for the severity of human envenomations, yet we understand very little about their venom yields and the factors influencing them. We investigated how size, specifically body length, influenced volume yield and protein concentration of electrically extracted venom in Scolopendra polymorpha and Scolopendra subspinipes. We also examined additional potential influences on yield in S. polymorpha, including relative forcipule size, relative mass, geographic origin (Arizona vs. California), sex, time in captivity, and milking history. Volume yield was linearly related to body length, and S. subspinipes yielded a larger length-specific volume than S. polymorpha. Body length and protein concentration were uncorrelated. When considering multiple influences on volume yield in S. polymorpha, the most important factor was body length, but yield was also positively associated with relative forcipule length and relative body mass. S. polymorpha from California yielded a greater volume of venom with a higher protein concentration than conspecifics from Arizona, all else being equal. Previously milked animals yielded less venom with a lower protein concentration. For both species, approximately two-thirds of extractable venom was expressed in the first two pulses, with remaining pulses yielding declining amounts, but venom protein concentration did not vary across pulses. Further study is necessary to ascertain the ecological significance of the factors influencing venom yield and how availability may influence venom use.

Scolopendra bites: a report of two cases and review of the literature

BACKGROUND

Centipedes are arthropods belonging to the class Chilopoda. Approximately 3000 species have been described. Centipedes are found more commonly in tropical and subtropical countries. Centipedes possess venomous fangs. The Scolopendra represent the best-known genus of centipede.

METHODS

We describe two cases of severe skin reactions caused by Scolopendra subspinipes bites.

RESULTS

Both patients were bitten on the hand. The clinical picture was characterized by severe erythematous edema. In addition, one patient presented with a blister. Both patients complained of severe pain. Laboratory examinations showed leukocytosis and an increase in erythrocyte sedimentation rate (ESR). Complete remission was achieved within two weeks by means of paracetamol and oral prednisone.

CONCLUSIONS

Western dermatologists should be aware of the possibility of severe skin reactions caused by centipede bites.

Acute ST-segment elevation myocardial infarction from a centipede bite

Acute myocardial infarction (AMI) following a centipede bite has been very rarely reported. Here, we describe a 22 year-old man who had ST-segment elevation AMI after a centipede bite. He presented with typical chest pain, electro and echocardiographic abnormalities, and elevated cardiac enzymes with normal coronary angiography. The probable mechanisms were described. Practitioners treating centipede bites shall not consider it lightly, as centipede envenomation may produce a variety of systemic and local manifestations in susceptible individuals.

On the venom system of centipedes (Chilopoda), a neglected group of venomous animals

Centipedes are among the oldest extant terrestrial arthropods and are an ecologically important group of soil and leaf litter predators. Despite their abundance and frequent, often painful, encounters with humans, little is known about the venom and venom apparatus of centipedes, although it is apparent that these are both quite different from other venomous lineages. The venom gland can be regarded as an invaginated cuticle and epidermis, consisting of numerous epithelial secretory units each with its own unique valve-like excretory system. The venom contains several different enzymes, but is strikingly different to most other arthropods in that metalloproteases appear to be important. Myotoxic, cardiotoxic, and neurotoxic activities have been described, most of which have been attributed to high molecular weight proteins. Neurotoxic activities are also unusual in that G-protein coupled receptors often seem to be involved, either directly as targets of neurotoxins or indirectly by activating endogenous agonists. These relatively slow responses may be complemented by the rapid effects caused by histamines present in the venom and from endogenous release of histamines induced by venom cytotoxins. The differences probably reflect the ancient and independent evolutionary history of the centipede venom system, although they may also be somewhat exaggerated by the paucity of information available on this largely neglected group.

Comparisons of ice packs, hot water immersion, and analgesia injection for the treatment of centipede envenomations in Taiwan

OBJECTIVE

To compare the effectiveness of ice packs and hot water immersion for the treatment of centipede envenomations.

METHODS

Sixty patients envenomated by centipedes were randomized into three groups and were treated with ice packs, hot water immersion, or analgesia injection. The visual analog score (VAS) for pain was measured before the treatment and 15 min afterward. Demographic data and data on local and systemic effects after centipede bites were collected. The VAS scores and the pain decrease (DeltaVAS) were compared between the three groups.

RESULTS

All patients suffered from pain at the affected sites; other local effects included redness (n = 49, 81.7%), swelling (n = 32, 53.3%), heat (n = 14, 23.3%), itchiness (n = 5, 8.3), and bullae formation (n = 3, 5.0%). Rare systemic effects were reported. All three groups had similar VAS scores before and after treatment. They also had similar effectiveness in reducing pain caused by centipedes bites (DeltaVAS = 2.55 +/- 1.88, 2.33 +/- 1.78, and 1.55 +/- 1.68, with ice packs, analgesia, and hot water immersion, respectively, p = 0.165).

CONCLUSION

Ice packs, hot water immersion, and analgesics all improved the pain from centipede envenomation. Ice pack treatment is a safe, inexpensive, and non-invasive method for pre-hospital management in patients with centipede envenomation.

[Necrotizing fasciitis and cellulitis of the upper limb resulting from centipede bite: two case reports]

Centipede bites occurring in tropical countries are rare, however vigilance must be exercised during activities in the open air and dwellings should be checked in the event of rain. The bite is very painful and can be accompanied by generalised signs. An initial wound disinfection and a check of antitetanus vaccination status is all that is usually needed to ensure an uneventful outcome. There are however, rare cases where local toxicity and a bacterial super-infection, often with Gram+ cocci, can lead to a cellulitis or even necrotizing fasciitis of the hand. The diagnosis of a centipede bite can be made by the double marks made by the fangs. Wound debridement and antibiotics led to a good outcome in both our cases.

Epidemiologic and clinical survey of victims of centipede stings admitted to Hospital Vital Brazil (São Paulo, Brazil)

We retrospectively analyzed 98 proven cases of centipede stings admitted to Hospital Vital Brazil, Butantan Institute, São Paulo, Brazil, between 1990 and 2007. Most stings occurred at the metropolitan area of São Paulo city (n=94, 95.9%), in the domiciles of patients (n=67, 68.4%), and during the warm-rainy season (n=60, 61.2%). The mean age of the victims was 32.0+/-18.8-years-old. Cryptops and Otostigmus genera were responsible for most cases. Around 86% of the patients sought medical care within 6h after the sting. Both lower (56.1 %) and upper limbs (41.8 %) were most frequently bitten, especially the feet and hands (89.8%). The most frequent local clinical manifestations were pain (94.9%), erythema (44.9%) and edema (21.4%), and the latter was mainly observed in patients bitten by Otostigmus spp. Supportive treatment was used in only 28.6% of the patients, namely administration of local anesthesia (9.2%) and systemic analgesia (13.3%). No sequels or complications were observed in patients, and the prognostic was benign.

Venomic analyses of Scolopendra viridicornis nigra and Scolopendra angulata (Centipede, Scolopendromorpha): Shedding light on venoms from a neglected group

Centipedes are venomous arthropods responsible for a significant number of non-lethal human envenomations. Despite this, information about the composition and function of their venom contents is scarce. In this study, we have used a 'structure to function' proteomic approach combining two-dimensional chromatography (2D-LC), electrospray ionization quadrupole/time-of-flight mass spectrometry (ESI-Q-TOF/MS), N-terminal sequencing and similarity searching to better understand the complexities of the venoms from two Brazilian centipede species: Scolopendra viridicornis nigra and Scolopendra angulata. Comparisons between the LC profiles and the mass compositions of the venoms of the two species are provided. The observed molecular masses ranged from 3019.62 to 20996.94Da in S. viridicornis nigra (total: 62 molecular masses) and from 1304.73 to 22639.15Da in S. angulata (total: 65 molecular masses). Also, the N-termini of representatives of 10 protein/peptide families were successfully sequenced where nine of them showed no significant similarity to other protein sequences deposited in the Swiss-Prot database. A screening for insecto-toxic activities in fractions from S. viridicornis venom has also been performed. Six out of the 12 tested fractions were responsible for clear toxic effects in house flies. This work demonstrates that centipede venoms might be a neglected but important source of new bioactive compounds.

Evolutionary biology of centipedes (Myriapoda: Chilopoda)

New insights into the anatomy, systematics, and biogeography of centipedes have put these predatory terrestrial arthropods at the forefront of evolutionary studies. Centipedes have also played a pivotal role in understanding high-level arthropod relationships. Their deep evolutionary history, with a fossil record spanning 420 million years, explains their current worldwide distribution. Recent analyses of combined morphological and molecular data provide a stable phylogeny that underpins evolutionary interpretations of their biology. The centipede trunk, with its first pair of legs modified into a venom-delivering organ followed by 15 to 191 leg pairs, is a focus of arthropod segmentation studies. Gene expression studies and phylogenetics shed light on key questions in evolutionary developmental biology concerning the often group-specific fixed number of trunk segments, how some centipedes add segments after hatching whereas others hatch with the complete segment count, the addition of segments through evolution, and the invariably odd number of leg-bearing trunk segments.

Acute myocardial infarction in a young man caused by centipede sting

It is known that insects can cause various clinical effects such as myocardial ischaemia and hypotension from vasospasm and the myocardial toxic effects of the venom and anaphylaxis. Although myocardial ischaemia resulting from centipede sting has been reported once before, myocardial injury has not. In this report, the authors present the case of a 20 year old male patient bitten by a centipede and admitted to the emergency room with chest pain, abnormal electrocardiographic findings, and increased cardiac enzymes (cardiac troponin T) suggesting acute myocardial infarction.

Scorpion stings in Australia: five definite stings and a review

Despite scorpions being locally abundant in many parts of Australia, scorpion sting is a poorly defined clinical condition in Australia. Many health-care workers are unaware of the effects of their stings and scorpions are often feared based on their international reputation. Five scorpion stings that occurred in different parts of Australia where the scorpion was caught at the time of the sting and identified by a professional arachnologist are reported in the present paper. The spectrum of clinical effects of scorpion stings in Australia and the potential for significant effects are discussed. These cases and recent prospective case series demonstrate that in Australia scorpion stings cause only minor effects. The main effect is localized pain lasting for several hours, associated less commonly with systemic effects, local numbness and paraesthesia. Most stings are from smaller scorpions from the family Buthidae and often occur indoors at night. The stings from Australian buthid scorpions cause more severe effects than from the larger species in the families Urodacidae (genus Urodacus) and Liochelidae (genus Liocheles).

Arthropods in dermatology

Arthropods are important in medicine for a multitude of reasons. Their bites and stings may induce allergic reactions, ranging from annoying to life-threatening. Many arthropod products are also capable of inciting allergic responses in sensitized persons. In recent years, bites and stings have gained greater attention owing to increased concern about disease transmission. A common hypersensitivity response to arthropod bites, stings, and products is papular urticaria. This eruption occurs primarily in children, who eventually "outgrow" this disease, probably through desensitization after multiple arthropod exposures. Papular urticaria is most often caused by fleas or bedbugs, but virtually any arthropod is capable of inducing such a reaction. Two arthropod classes of medical importance are the Arachnida (spiders, scorpions, ticks, and mites) and the Insecta (lice, fleas, bedbugs, flies, bees, and ants). Animals in these two classes are probably responsible for more morbidity and mortality worldwide than are any other group of venomous creatures. In general, the diagnosis of arthropod bites and stings is dependent on maintenance of a high index of suspicion and familiarity with the arthropod fauna not only in one's region of practice, but also in the travel regions of one's patients. Learning objective At the completion of this learning activity, participants should be familiar with the clinical manifestations caused by a variety of arthropods as well as the treatment and possible sequelae of arthropod attacks.

Prospective study of centipede bites in Australia

BACKGROUND

There are limited reports of definite bites by centipedes with expert identification, which are required for attribution of particular clinical effects to different species.

OBJECTIVE

To describe the clinical effects of centipede bites in Australia.

METHODS

Prospective study of calls regarding centipede exposures to a state poison information center, from December 2000 to March 2002. Information collected included demographics, details of the exposure, local effects, systemic effects, and treatment. Collected centipedes were identified by an expert. All subjects were followed until clinical effects had resolved.

RESULTS

Of 48 centipede exposures, 3 were centipede ingestions with no adverse effects and one was a contact reaction to the centipede that resulted in erythema and delayed itchiness. Of 44 definite centipede bites, the centipedes obtained and formally identified in 14 cases were from the genera Scolopendra (5), Cormocephalus (6), and Ethmostigmus (3). Of these 14 bites, 13 occurred distally (hands or feet). Pain occurred in all 14 cases and was severe in 7 patients. Redness/red mark occurred in 53%, swelling/raised area in 43%, and itchiness in 14%. No systemic effects were reported. Ethmostigmus spp. and Scolopendra spp. caused more severe effects. Of the bites, 57% occurred indoors and 50% at night. Treatment consisted of supportive measures including ice packs and simple analgesia, and 4 patients reported pain relief after immersing the bite area in hot water. Similar clinical effects were reported in the other 30 definite centipede bites.

CONCLUSIONS

Australian centipede bites cause minor effects with moderate to severe pain, associated with localized swelling and erythema in bites by the genera Ethmostigmus and Scolopendra. Hot water immersion may potentially be beneficial for centipede bites. The genus Scolopendra occurs worldwide and the results may have international applicability.