Australian scorpion stings: a prospective study of definite stings

Study of the Acute Toxicity of Scorpion Leiurus macroctenus Venom in Rats

Background

The expansion of the territory of human habitation leads to inevitable interference in the natural range of distribution of one or another species of animals, some of which may be dangerous for human life. Scorpions-the Arachnida class and order Scorpiones-can be considered as such typical representatives. Scorpions of the Buthidae family pose a particular danger to humans. However, LD50 has not yet been defined for many species of this family, in particular, new representatives of the genus Leiurus. Leiurus macroctenus is a newly described species of scorpion distributed in Oman, and the toxicity of its venom is still unknown. Estimating the LD50 of the venom is the first and most important step in creating the antivenom and understanding the medical significance of the researched animal species. The purpose of this study was to determine the lethal dose (LD100), the maximum tolerated dose (LD0), and the average lethal dose (LD50) in rats when using Leiurus macroctenus scorpion venom.

Methods and Results

15 sexually mature scorpions were used in the study, which were kept in the same conditions and milked by a common method (electric milking). For the study, 60 male rats were used, which were injected intramuscularly with 0.5 ml of venom solution with a gradual increase in the dose (5 groups, 10 rats in each), and 10 rats were injected intramuscularly with physiological solution as control group. LD calculations were done using probit analysis method in the modification of the method by V.B. Prozorovsky. The LD0 of Leiurus macroctenus scorpion venom under the conditions of intramuscular injection was 0.02 mg/kg, LD100 was 0.13 mg/kg, and LD50 was 0.08 ± 0.01 mg/kg.

Conclusions

The analysis of scientific publications and other sources of information gives reason to believe that Leiurus macroctenus has one of the highest values of LD50 not only among scorpions but also among all arthropods in the world. All these point to the significant clinical importance of this species of scorpion and require further research that will concern the toxic effect of its venom on various organ systems. Determining the LD50 of the venom for new scorpion species is crucial for creating effective antivenoms and understanding the medical implications of envenomation by this species.

Scorpion sting in Hafizabad, Pakistan: Facility based epidemiological study

Scorpion envenomation is a widespread issue in tropical and subtropical countries. In the present study epidemiology of scorpion sting cases and potential treatment options in district Hafizabad, Pakistan are documented. Hafizabad city and the adjacent villages were selected for the data collection. Age, gender, time, site of scorpion sting on the body, scorpion sting symptoms, number of patients obtaining medical attention and the number of fatalities (if any) were noted. Data showed that scorpion envenomation often occurs in people between the ages of 16-47 years. There were more female victims (55%) and most of the scorpion sting incidences (55.49%) occurred between 07 PM and 02 AM Among body parts, both the hands (41.71%) and feet (48.57%) were more vulnerable to scorpion stings. In rural areas, the incidences of scorpion stings were higher (68.57%). The reported symptoms of scorpion stings include pain, hypertension, nausea and allergy. Out of all the victims, only 56.05% sought treatment from health care units as well as traditional medicine practitioners. However, others (43.94%) fully healed on their own without any treatment. People were using different types of plant-based materials and dead scorpions with mustard oil as a potent remedy against scorpion stings. Moreover, in the health care units there was no antivenom available and medical staff usually used common pain killers such as Xylocain and Lignocain for the treatment of scorpion sting.

Relationship Between Scorpion Stings Events and Environmental Conditions in Mainland France

In the world, the impact of environmental conditions on the number of scorpion events was evaluated in North Africa,Middle East, and the Amazonian region but not in Europe. In mainland France, scorpion species described are Buthus occitanus (Amoreux, 1789), Belisarius xambeui (Simon, 1879) and 4 Euscorpiidae: Euscorpius concinnus (Koch, 1837), Euscorpius italicus (Herbst, 1800), Euscorpius tergestinus (Koch, 1837), and Tetratrichobothrius flavicaudis (De Geer, 1778). We aimed to describe the impact of environmental conduction on the number of scorpion events. For this, a retrospective multi-center study was conducted with data from the French poison control centers files about scorpion events between 1 January 2011 and 31 December 2020. During the study period, 975 incoming calls for scorpion events were recorded and 574 were related to scorpions native to mainland France and Corsica: B. occitanus (n = 86), Euscorpiidae species (n = 222), B. xambeui (n = 1), and undetermined species (n = 265). Cases were mostly reported along the Mediterranean coast, along rivers, and in cities with a trading port. The number of scorpion events was linked to the rivers' water level, rivers' flow, temperature, sunshine, and pluviometry (P < 0.05 for all variables). B. occitanus need warmest and driest environment than Euscorpiidae spp. A link between the severity of the envenoming and climatic condition or seasonality was not demonstrated.

Love bites - Do venomous arachnids make safe pets?

With a global estimate of tens of thousands of arachnid enthusiasts, spiders and scorpions are gaining increasing popularity as pets in industrialised countries in Europe, Northern America and Asia. As most spiders and all scorpions are venomous and due to their mostly negative image in the public media, several governments are already considering introducing legislation to regulate the domestic care of potentially dangerous captive animals. We aimed to investigate the circumstances and effects of exposure to arachnids kept in captivity. Thus, we collected and analysed data from 354 self-reported bites and stings attributed to pet arachnids. Our data revealed that on average there were less than 20 recorded envenomations per year with ~90% preventable by due care. We also categorized the severity of the resulting symptoms and found that the vast majority of symptoms were either local (60.7%) or minor (32.8%), 5.4% were asymptomatic, only 1.1% were severe and no fatalities were recorded. Based on our database of bite and sting reports, we performed a risk assessment for arachnid pet ownership and concluded that, with the proper care, arachnids can be safely kept as pets and pose a lower risk than many other recreational activities.

Pioneering Study on Rhopalurus crassicauda Scorpion Venom: Isolation and Characterization of the Major Toxin and Hyaluronidase

Scorpionism is responsible for most accidents involving venomous animals in Brazil, which leads to severe symptoms that can evolve to death. Scorpion venoms consist of complexes cocktails, including peptides, proteins, and non-protein compounds, making separation and purification procedures extremely difficult and time-consuming. Scorpion toxins target different biological systems and can be used in basic science, for clinical, and biotechnological applications. This study is the first to explore the venom content of the unexplored scorpion species Rhopalurus crassicauda, which inhabits exclusively the northernmost state of Brazil, named Roraima, and southern region of Guyana. Here, we pioneer the fractionation of the R. crassicauda venom and isolated and characterized a novel scorpion beta-neurotoxin, designated Rc1, and a monomeric hyaluronidase. R. crassicauda venom and Rc1 (6,882 Da) demonstrated pro-inflammatory activities in vitro and a nociceptive response in vivo. Moreover, Rc1 toxin showed specificity for activating Na_v1.4, Na_v1.6, and BgNa_v1 voltage-gated ion channels. This study also represents a new perspective for the treatment of envenomings in Roraima, since the Brazilian scorpion and arachnid antivenoms were not able to recognize R. crassicauda venom and its fractions (with exception of hyaluronidase). Our work provides useful insights for the first understanding of the painful sting and pro-inflammatory effects associated with R. crassicauda envenomings.

Dangerous arachnids-Fake news or reality?

The public perception of spiders and scorpions is skewed towards the potential harm they can inflict in humans, despite recent scientific evidence that arachnid venom components might be useful as bioinsecticides or even human therapeutics. Nevertheless, arachnids are becoming more popular as pets in Europe, America and Asia, raising the question for regulatory agencies in these regions as to whether they need to take measurements to protect their citizens. In order to decide upon the necessary regulatory steps, they first need to determine which arachnids are actually dangerous to humans. This review therefore provides an overview of the current literature on verified bites and stings from spiders and scorpions with the aim of assessing their potential danger for human health. As a guideline, we also provide a list of those arachnid genera that we consider as potentially dangerous, which includes 10 spider and 11 scorpion genera. The arachnid genera classified as dangerous comprise less than a quarter of all extant scorpion species and only 0.5% of all spiders species, with the actual number most likely being much lower than that, as not all species in those genera might turn out to pose an actual threat for humans. In conclusion, we found that only a small percentage of scorpions and a minute percentage of all spiders can be considered as potentially dangerous to humans. While in some countries of origin the high incidence of envenomations by dangerous arachnids can result in a serious problem to the health system, we assessed the risk that the same species pose when kept as pets under controlled maintenance conditions as significantly lower.

Clinical and Epidemiological Aspects of Scorpionism in the World: A Systematic Review

OBJECTIVE

Scorpion stings are registered worldwide, but the incidence and the features of the envenomations vary depending on the region. The aim of this review was to summarize the epidemiological, clinical, diagnostic, and therapeutic data worldwide regarding humans stung by scorpions.

METHODS

A systematic review of the literature was conducted through the online databases of the Virtual Health Library (VHL), which hosts Medline and the Latin American and Caribbean Center on Health Sciences Informational (LILACS) database. We selected articles published between January 1, 2002 and July 31, 2014.

RESULTS

Scorpion envenomation reports were found throughout the world, mainly in subtropical and tropical regions. The clinical manifestations were sympathetically and parasympathetically mediated, depending on the species of scorpion. Some of the most common severe complications of scorpionism included respiratory distress syndrome, pulmonary edema, cardiac dysfunction, impaired hemostasis, pancreatitis, and multiple organ failure. Scorpion envenomation could be classified as mild, moderate, and severe, and the therapeutic approach was based on the case severity. The treatment comprised 3 components: symptomatic measures, vital functions support, and injection of antivenom. Moreover, the time that elapsed between the sting and administration of the appropriate medical care was extremely important to the patient's prognosis.

CONCLUSIONS

The large number of scorpion stings worldwide is concerning and reaffirms the need for new prevention measures and policies to reduce the incidence, prevalence, morbidity, and mortality rates from these poisonous arachnids.

A randomized trial comparing intravenous paracetamol, topical lidocaine, and ice application for treatment of pain associated with scorpion stings

OBJECTIVE

Appropriate treatment for scorpion-associated pain was not previously studied in detail in the literature. The aim of this study was to compare the efficacy of three treatment modalities in patients with painful scorpion stings using visual analog scale (VAS) scores.

MATERIALS AND METHODS

A randomized study was carried out during a 1-year period in patients with scorpion stings who did not have any systemic signs or symptoms. Patients were treated with intravenous paracetamol, topical lidocaine, or ice application. Pain intensity was evaluated using VAS score at the time of presentation to emergency department and at 30th, 60th, 120th, and 240th minutes. Changes in VAS scores from baseline were recorded.

RESULTS

A total of 130 patients were included in the statistical analysis. Significant reduction in pain intensity was observed with topical lidocaine group when compared with the ice application group (p < 0.001) and paracetamol group (p < 0.001) in all selected time intervals. The median reduction in scores at 30 min after therapeutic intervention was 25.0 mm for topical lidocaine, 14.5 mm for ice application, and 10.0 mm for intravenous paracetamol. No adverse events were reported.

DISCUSSION

Our results revealed that topical lidocaine is superior to both intravenous paracetamol and local ice application and its effect lasts several hours after envenomation.

CONCLUSION

Topical lidocaine is an effective and safe treatment in scorpion sting associated with pain in patients with nonsystemic signs and symptoms.

Scorpion stings presenting to an emergency department in Singapore with special reference to Isometrus maculatus

OBJECTIVE

We describe the epidemiology and clinical features of scorpion stings presenting to an emergency department in Singapore, including that of the venomous species Isometrus maculatus. A management approach to scorpion stings is proposed.

METHODS

A retrospective study was done for patients from 2004 to 2009. Cases were identified by searching through emergency department records with ICD code E905, inpatient records, and the hospital toxicology service records. Identification of species was assisted by the Venom and Toxin research program at the National University of Singapore.

RESULTS

A total of 13 cases of scorpion stings were identified. Eleven stings occurred locally, and the remaining 2 stings occurred in neighboring countries. The most common presenting symptoms were pain (92%), numbness (31%), and weakness (23%) confined to the region of the sting. The most common clinical signs recorded were redness (77%), tenderness (77%), and swelling (46%). Only 2 patients had significant alterations of vital signs: 1 had hypertension and the other had hypotension from anaphylaxis. Three patients experienced complications (abscess formation, anaphylaxis, cellulitis) requiring inpatient management. There were no fatalities, and all patients made a good recovery. Three cases were identified to be stings from I maculatus. These cases occurred locally, and mainly had clinical features of pain, redness, and mild regional numbness.

CONCLUSIONS

Scorpion stings are uncommon presentations to the emergency department. Most stings cause local reactions that can be managed with supportive treatment. Stings by I maculatus were observed to cause mild, self-limiting effects.

Neurological effects of venomous bites and stings: snakes, spiders, and scorpions

Snake and spider bites, as well as scorpion sting envenoming, are neglected diseases affecting millions of people all over the world. Neurological complications vary according to the offending animal, and are often directly related to toxic effects of the venom, affecting the central nervous system, the neuromuscular transmission, the cardiovascular system, or the coagulation cascade. Snake bite envenoming may result in stroke or muscle paralysis. Metalloproteinases and other substances (common in vipers and colubrids) have anticoagulant or procoagulant activity, and may induce ischemic or hemorrhagic strokes. The venom of elapids is rich in neurotoxins affecting the neuromuscular transmission at either presynaptic or postsynaptic levels. The clinical picture of scorpion sting envenoming is dominated by muscle weakness associated with arterial hypertension, cardiac arrythmias, myocarditis, or pulmonary edema. These manifestations occur as the result of release of catecholamines into the bloodstream or due to direct cardiac toxicity of the venom. Cerebrovascular complications have been reported after the sting of the Indian red scorpion. Intracranial hemorrhages occur in the setting of acute increases in arterial blood pressure related to sympathetic overstimulation, and cerebral infarctions are related to either cerebral hypoperfusion, consumption coagulopathy, vasculitis, or cardiogenic brain embolism. Three main syndromes result from spider bite envenoming: latrodectism, loxoscelism, and funnel-web spider envenoming. Latrodectism is related to neurotoxins present in the venom of widow spiders. Most cases present with headache, lethargy, irritability, myalgia, tremor, fasciculation, or ataxia. Loxoscelism is caused by envenoming by spiders of the family Sicariidae. It may present with a stroke due to a severe coagulopathy. The venom of funnel-web spiders also has neurotoxins that stimulate neurotransmitter release, resulting in sensory disturbances and muscle paralysis. Proper management of the envenomed patient, including prompt transport to the hospital, correction of the hemostatic disorder, ventilatory support, and administration of antivenom, significantly reduce the risk of neurological complications which, in turn, reduce the mortality and improve the functional outcome of survivors.

Escorpionismo por Tityus pusillus Pocock, 1893 (Scorpiones; Buthidae) no Estado de Pernambuco

Apresentamos neste trabalho os primeiros relatos de acidente escorpiônico causado pela espécie Tityus pusillus (Buthidae). Os acidentes ocorreram no ambiente doméstico, na área rural situada nas cidades de Paudalho e São Lourenço da Mata, Pernambuco, Brasil. Os dois casos descritos, uma criança e uma mulher grávida, foram classificados como leve e moderado, respectivamente. Os sintomas clínicos apresentados foram distúrbios locais (dor e parestesia) e distúrbios sistêmicos (calafrios, tontura, cefaléia e vômito). Esses registros permitem incluir Tityus pusillus como uma espécie de importância médica no Brasil.

Epidemiology of scorpionism: a global appraisal

The scorpionism is an actual public health problem in several parts of the world because, either incidence, or severity of envenomations is high and managed with difficulty by health services, or for these two reasons at the same time. The treatment of scorpion envenomation is complex and controversial, in particular regarding the utility of the antivenoms and symptomatic treatments that must be associated. The authors reviewed the literature of last 30 years to discuss the epidemiologic importance of scorpionism and to point out the principal therapeutic or preventive measures. According to the most recent studies, seven areas were identified as at risk: north-Saharan Africa, Sahelian Africa, South Africa, Near and Middle-East, South India, Mexico and South Latin America, east of the Andes. These involve 2.3 billion at risk population. The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%). Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher. Improvement of therapeutic management would reduce the lethality very significantly.

Arachnid toxinology in Australia: From clinical toxicology to potential applications

The unique geographic isolation of Australia has resulted in the evolution of a distinctive range of Australian arachnid fauna. Through the pioneering work of a number of Australian arachnologists, toxinologists, and clinicians, the taxonomy and distribution of new species, the effective clinical treatment of envenomation, and the isolation and characterisation of the many distinctive neurotoxins, has been achieved. In particular, work has focussed on several Australian arachnids, including red-back and funnel-web spiders, paralysis ticks, and buthid scorpions that contain neurotoxins capable of causing death or serious systemic envenomation. In the case of spiders, species-specific antivenoms have been developed to treat envenomed patients that show considerable cross-reactivity. Both in vitro and clinical case studies have shown they are particularly efficacious in the treatment of envenomation by spiders even from unrelated families. Despite their notorious reputation, the high selectivity and potency of a unique range of toxins from the venom of Australian arachnids will make them invaluable molecular tools for studies of neurotransmitter release and vesicle exocytosis as well as ion channel structure and function. The venoms of funnel-web spiders, and more recently Australian scorpions, have also provided a previously untapped rich source of insect-selective neurotoxins for the future development of biopesticides and the characterisation of previously unvalidated insecticide targets. This review provides a historical viewpoint of the work of many toxinologists to isolate and characterise just some of the toxins produced by such a unique group of arachnids and examines the potential applications of these novel peptides.

Gastrointestinal manifestations in severe scorpion envenomation

OBJECTIVES

To evaluate the type and incidence of gastrointestinal manifestations secondary to scorpion envenomation and their prognostic significance.

PATIENTS AND METHODS

All patients admitted to our ICU for scorpion envenomation were included in this retrospective chart review of a 13-year period (1990 - 2002).

RESULTS

During the study period, 951 patients were admitted for scorpion envenomation and 72 (7.6%) died. Ages ranged from 0.5 to 90 years with a mean of 14.7 +/- 17.4 years. Gastrointestinal symptoms were present in 700 patients (73.6%): nausea in 24 (2.5%), vomiting in 687 (72.2%) and diarrhea in 41 patients (4.3%). At univariate analysis, the presence of diarrhea was associated with a fatal outcome (P < 0.05). Diarrhea was also correlated with other indicators of severe envenomation and poor prognosis: respiratory failure (P = 0.01), neurological failure (P < 0.0001), liver failure (P < 0.0001) and low blood pressure requiring catecholamine support (P = 0.02). The multivariate analysis showed that young age (age less than 5 years), fever > 38.5 degrees C, neurological failure and pulmonary edema were independent factors of severity. Digestive disorders were more frequent in children and in this subgroup diarrhea appeared to be associated with poor outcome. In a subset of patients for whom data were available, fatal cases demonstrated significantly higher liver enzymes levels on admission.

CONCLUSION

In Tunisia, gastrointestinal symptoms are often observed in severe scorpion envenomations, especially in young patients. In children, diarrhea and elevated liver enzymes are associated with poor prognosis.

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).