Scorpionism by Tityus silvestris in eastern Brazilian Amazon

Exploring the potential of Brazilian Amazonian scorpion venoms: A comprehensive review of research from 2001 to 2021

The Amazon biome is home to many scorpion species, with around two hundred identified in the region. Of these, forty-eight species have been reported in Brazil so far and six of them are of medical importance: Tityus apiacas, T. metuendus, T. obscurus, T. raquelae, T. silvestris, and T. strandi. Three non-medically important species have also been studied: Opisthanthuscayaporum, Brotheas amazonicus and Rhopalurus laticauda. The venom of the scorpion T. obscurus is the most studied, followed by O. cayaporum. We aim to update the study of these Amazonian scorpion species. We will explore the harmful and beneficial properties of scorpion venom toxins and how they could be applied in drug development. This systematic review will focus on collecting and analyzing venoms from scorpions in Brazil. Only papers on Amazonian scorpion venom studies published between 2001 and 2021 (scientific articles, theses, and dissertations) were selected, based on the lists of scorpions available in the literature. Species found in the Amazon but not confirmed to be Brazilian were omitted from the review. Theses and dissertations were chosen over their derived articles. We found 42 eligible studies (13 theses, 27 articles and 2 patents) out of 17,950 studies and a basic statistical analysis was performed. The literature showed that T. obscurus was the most studied venom with 28 publications, followed by O. cayaporum with seven articles, B. amazonicus with four articles, T. metuendus with two article and R. laticauda with one article. No publication on the characterization of T. silvestris and T. apiacas venoms were found during the reviewed period, only the clinical aspects were covered. There is still much to be explored despite the increasing number of studies conducted in recent years. Amazonian scorpions have promising potential for pharmaceutical and clinical applications.

First report of an accident caused by Jaguajir agamemnon (C.L. Koch, 1839) (Scorpiones, Buthidae) in Paraná state, Brazil

We report the first pediatric case of a Jaguajir agamemnon scorpion sting. This case occurred in the state of Paraná and is the first record of this species in southern Brazil. The patient was admitted within 15 min, with pain, local edema, erythema, whole-body pruritus, and tongue paresthesia within the first two hours, which disappeared thereafter. The patient's condition was considered mild, with a positive outcome, and she recovered completely.

Pioneering in vitro characterization of macrophage response induced by scorpion venoms from the Brazilian Amazon

There are several scorpion species of medical relevance around the world. Some of them are well characterized by their toxins and clinical outcomes. Brazilian Amazon has a great amount of these arthropods that have an impact in the scorpionism events specifically in this region of Brazil. Recently, several studies pointed out the immune system activation during scorpion envenouming as an important facet of scorpionism, inducing a sepsis-like state that culminates in clinical severity and death. In this work, we characterized the macrophage response of three species of clinical relevance in Brazilian Amazon: Tityus silvestris, T. metuendus and T. obscurus and one specie with no toxic effects to humans, Brotheas amazonicus. All the four species analyzed were able to induce pro- and anti-inflammatory cytokine production in a J774.1 murine macrophage model. This activation was dependent on TLR2/TLR4/MyD88 activation and abolished by TLRs antagonists. These results suggest that the venoms of the four species analyzed were able to induce macrophage response in agreement to the well-established immune activation by T. serrulatus venom. Our findings provide new insights into the clinical repercussions of scorpionism of uncharacterized species and point to new biotechnological applications of these venoms and possible supportive therapies in scorpionism.

Scorpion envenomation in Brazil: Current scenario and perspectives for containing an increasing health problem

Opportunistic scorpion species can colonize urban environments, establishing high-density communities that enhance the chances of human accidents. This scenario has been taking place in Brazil, in which some Tityus species have taken city centers, causing an explosion in the number of scorpion envenoming cases. The characteristics of this scorpionism epidemic in Brazil is discussed in the present work. The number of Brazilian scorpion stings has surpassed 120,000 cases in 2017, and has been maintained above this number ever since, representing a more than 3-fold increase in 10 years, which was higher than the number of cases for most of the neglected tropical diseases in the country. The escalation in scorpionism cases is even higher in some regions of Brazil. Fortunately, the proportion of mild cases has also increased in the analyzed period, as well as the number of victims seeking for medical attention within the first hour after the accident. The species Tityus serrulatus, Tityus stigmurus, Tityus bahiensis, and Tityus obscurus are traditionally accountable for most of the scorpion accidents in different regions of Brazil, but other species deserve to be closely watched. Despite scorpionism being a notable health problem in Brazil, accident prevention and pest control regarding this venomous animal have not been properly addressed by the scientific community nor by policy makers. Therefore, this review also aims to point possible fields of research that could help to contain the aggravation of the current scorpionism landscape in Brazil.

Amazonian scorpions and scorpionism: integrating toxinological, clinical, and phylogenetic data to combat a human health crisis in the world's most diverse rainfores

Venom from Amazonian scorpions of the genus Tityus contains components capable of eliciting a distinct clinical, mostly neurological, syndrome. This contrasts with the mainly autonomic manifestations produced after envenomation by congeneric southern and northern South American species. Herein, we summarize Pan-Amazonian scorpionism by synthesizing available toxinological, clinical, and molecular data gathered from all affected areas in Amazonia, including Brazil, Ecuador, Colombia, Peru, Venezuela, and French Guiana. We searched multiple databases, as well as our own records, for reports of scorpion envenomations in Amazonia by confirmed Tityus spp., and compared the clinical manifestations. To help uncover clinical and venom relationships among problematic species, we explored phylogenetic relationships with a rate-calibrated analysis of mitochondrial COI data from available species. The possible existence of diversity gradients for venom toxic and immunogenic components despite the predicted strong phylogenetic association among species is underscored by discussed clinical and toxinological findings. A multicentric effort, involving all nations affected by this neglected disease, is urgently needed to offer alternatives for treating and understanding this pathology, including the preparation of neutralizing antibodies with a broad range of efficacy.

Scorpion species of medical importance in the Brazilian Amazon: a review to identify knowledge gaps

Scorpionism is a relevant medical condition in Brazil. It is responsible for most accidents involving venomous animals in the country, which leads to severe symptoms that can evolve to death. In recent years, an increase of almost 50% in the incidence of scorpionism has been observed in the Northern Region, where the highest severity of envenoming has been notified since the beginning of the 21st century. This review aims to provide an in-depth assessment of public data and reports on symptoms and epidemiology of envenoming, ecological aspects of scorpions, and characterization of venoms and toxins to access the gaps that need to be filled in the knowledge of the scorpion species of medical importance from the Brazilian Amazon. A systematic search using the string words "Amazon" and "scorpion" was performed on 11 databases. No restriction on date, language or status of the publication was applied. Reports not related to the Brazilian Amazon were excluded. Therefore, 88 studies remained. It is shown that populations of scorpions of medical importance, even of the same species, may present significant toxic variations peculiar to some regions in the Brazilian Amazon, and commercial scorpion antivenoms were not able to shorten the intensity and duration of neurological manifestations in patients stung by T. silvestris, T. apiacas or T. obscurus. It is also highlighted that the toxins responsible for triggering these alterations have not been elucidated yet and this is a fruitful field for the development of more efficient antivenoms. Furthermore, the geographic distribution of scorpions of the genus Tityus in the Brazilian Amazon was revised and updated. The cumulative and detailed information provided in this review may help physicians and scientists interested in scorpionism in the Brazilian Amazon.

Vulnerable areas to accidents with scorpions in Brazil

OBJECTIVE

To identify areas that present a higher risk of exposure to accidents with scorpions in Brazil.

METHODS

We used techniques of spatial prioritisation to determine the most vulnerable localities to envenomation by four scorpion species. Our prioritisation integrated ecological niche models with health investment, antivenin availability, access to health care facilities and metrics of human impact data.

RESULTS

The ecological niche models indicated that three scorpion species (Tityus bahiensis, Tityus serrulatus, and Tityus stigmurus) are more associated with human population density, while T. obscurus demonstrated a strong association with temperature variations during the year. Spatial prioritisation indicated that the areas with higher risk exposure to accidents with scorpions are in northern and northeastern Brazil. Alternatively, more isolated but densely populated areas in the southeastern and central regions also emerged as a priority.

CONCLUSION

Mapping areas where humans are more likely to interact with scorpions can assist in the design of efficient public health policies.

Clinical profile of confirmed scorpion stings in a referral center in Manaus, Western Brazilian Amazon

Scorpion envenomations are a major public health problem in Brazil, and most medically important cases are attributable to the Tityus genus. The objective of this study is to describe the clinical and epidemiological aspects of a series of 151 cases of confirmed scorpion stings, which were treated at the hospitals of two cities in the Western Brazilian Amazon, between June 2014 and December 2019. This study shows that the genus Tityus was the most prevalent. Tityus (Atreus) metuendus (Pocock, 1897) was responsible for the greatest number of cases (68.2%), followed by Tityus (Archaeotityus) silvestris (Pocock, 1897) (14.6%). Most of the envenomations involved males (53.6%), and analysis showed a slight predominance in the group from 40 to 49 years (22.5%). The most affected body regions were feet (49.0%) and hands (31.8%). The time elapsed between the accident and medical care was ≤6 h in 92.1% of cases. Regarding clinical severity, classes I (80.8%) and II (15.9%) predominated. However, there were five (3.3%) class III cases; four for T. metuendus and one for T. silvestris. The most frequent local and systemic manifestations were, respectively, pain (84.1%), paresthesia (34.4%) and mild edema (25.8%), and nausea (9.3%) and myoclonia (8.6%). The clinical manifestations were similar among the patients stung by the different species of scorpions. There were no differences between the manifestations of envenomation caused by T. metuendus, T. silvestris and T. raquelae. For victims of T. apiacas, a higher frequency of piloerection and myoclonia was observed, and was described by the affected patients as a 'sensation of receiving an electric shock' throughout the body. No deaths were registered. The species of greatest epidemiological importance in Manaus is T. metuendus, a species that leads to clinical pictures that do not differ substantially from those observed in other Brazilian regions. T. apiacas causes neurological manifestations that differed from other Tityus species. Our findings suggest that the available antivenoms have little effectiveness when used in the treatment of envenomations by some Amazonian scorpions.

First report of scorpionism caused by Tityus serrulatus, described by Lutz and Mello, 1922 (Scorpiones, Buthidae), a species non-native to the state of Pará, Brazilian Amazon

This reports a case of scorpionism caused by Tityus serrulatus. A male adult was stung while unloading bananas at the supply center in Belém, Pará, Brazil. The bananas originated in another state (Bahia) and were brought to Belém by truck. The patient presented with pain, edema, and erythema at the sting site, and was classified as low-risk. The specimen was identified as T. serrulatus and symptomatic treatment and clinical observation were advised. The patient was discharged later without further complications. This is the first known envenomation caused by T. serrulatus, a non-native species to Pará, in the Brazilian Amazon.

Avaliação do uso de soros antivenenos na emergência de um hospital público regional de Vitória da Conquista (BA), Brasil

Resumo O presente estudo tem como objetivo caracterizar o perfil epidemiológico de vítimas de acidentes escorpiônicos e ofídicos e avaliar a adequação das prescrições de soros antivenenos. Estudo transversal cujas fontes de dados foram as fichas de notificação de acidentes por animais peçonhentos do Sistema de Informação de Agravos de Notificação no município de Vitória da Conquista (BA), Brasil. Foram incluídas as informações de acidentes escorpiônicos ou ofídicos no período entre julho de 2016 e junho de 2017 atendidos no município. Os dados obtidos e as variáveis de interesse foram analisadas de acordo com as perguntas deste estudo. No período observado foram atendidas 293 vítimas de acidentes por animais peçonhentos. Destas, 149 (50,9%) foram homens e 114 (38,9%) possuíam entre 20 a 59 anos. Foram 235 (80,9%) casos de escorpionismo e 58 (19,1%) de ofidismo. Destes, 203 (69,3%) foram classificados como leves e em 200 (68,5%) casos foi prescrita soroterapia para estes pacientes. Quanto à adequação das prescrições, 172 (59,7%) foram julgadas inadequadas e destas, o uso de número de ampolas acima do indicado foi a mais frequente. A prescrição inapropriada de soros antivenenos ocorreu em aproximadamente em 60% dos casos avaliados. Apesar disso, a maioria dos acidentes foi classificada como leve, em homens jovens.

Myocardial injury induced by scorpion sting envenoming and evidence of oxidative stress in Egyptian children

In the present study, 45 children in Upper Egypt (less than 16 years old) were admitted to the Pediatric Intensive Care Unit for scorpion envenomation (SE). They were compared with 30 apparently healthy children of matching age and sex as controls. Out of the studied victims, 35 children (78%) showed signs of severe envenomation, while 10 victims (22%) showed signs of mild envenomation. The case fatality was 33%. The serum levels of cardiac markers, cardiac troponin T (cTnT) and I (cTnI), as well as the enzymatic activities of creatine kinase-MB (CPK-MB) and lactate dehydrogenase (LDH) were determined for both victims and controls. In addition, the serum levels of oxidative stress markers, nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH) and zinc (Zn) were measured. Electrocardiography and echocardiography were done. All the envenomed victims showed significantly higher mean values of cTnT, cTnI, CPK-MB and LDH than control group. These cardiac markers were elevated in severe cases and in non survivors in comparison with mild cases and survivors respectively. Furthermore, the serum levels of NO and MDA were significantly higher while the serum levels of SOD, GSH and Zn were significantly lower in all envenomed victims than the controls (p < 0.05 for all). There were no significant differences in the serum levels of oxidative stress markers among severe and mild cases or between survivors and non survivors victims. There were no significant correlations between the serum levels of cardiac markers and the oxidative stress markers in envenomed victims. In conclusions, oxidative stress occurs in scorpion envenomed children, but does not determine prognosis. Cardiac markers, but not the oxidative stress, remain the most important determining factor for the severity and the outcome of SE.

Effects of Brazilian scorpion venoms on the central nervous system

In Brazil, the scorpion species responsible for most severe incidents belong to the Tityus genus and, among this group, T. serrulatus, T. bahiensis, T. stigmurus and T. obscurus are the most dangerous ones. Other species such as T. metuendus, T. silvestres, T. brazilae, T. confluens, T. costatus, T. fasciolatus and T. neglectus are also found in the country, but the incidence and severity of accidents caused by them are lower. The main effects caused by scorpion venoms - such as myocardial damage, cardiac arrhythmias, pulmonary edema and shock - are mainly due to the release of mediators from the autonomic nervous system. On the other hand, some evidence show the participation of the central nervous system and inflammatory response in the process. The participation of the central nervous system in envenoming has always been questioned. Some authors claim that the central effects would be a consequence of peripheral stimulation and would be the result, not the cause, of the envenoming process. Because, they say, at least in adult individuals, the venom would be unable to cross the blood-brain barrier. In contrast, there is some evidence showing the direct participation of the central nervous system in the envenoming process. This review summarizes the major findings on the effects of Brazilian scorpion venoms on the central nervous system, both clinically and experimentally. Most of the studies have been performed with T. serrulatus and T. bahiensis. Little information is available regarding the other Brazilian Tityus species.

Epidemiological study of scorpion stings in the Rio Grande do Norte State, Northeastern Brazil

This communication is a retrospective epidemiological study of the scorpion sting cases recorded from 2007 to 2014 in the Rio Grande do Norte State, Northeastern Brazil. The data was collected from the Injury Notification Information System database of the Health Department of Rio Grande do Norte State. A total of 20,555 cases were studied. The cases were distributed over all months of the period studied and occurred mainly in urban areas. Victims were predominantly 20-29 year-old women. Most victims were stung on the foot and received medical care within 1-3 h after being stung. The cases were mostly classified as mild and progressed to cure. Scorpion stings in Rio Grande do Norte State are an environmental public health problem that needs to be monitored and controlled throughout the year.