A Bibliometric Analysis of Scorpionism Epidemiology in Tropical Health

The linear function graph depicts a consistent upward trend in the studies developed and published from 1950 to 2022. Over the eight decades covered by this review study, there was an average of 18.12 publications per decade and a standard deviation of 24.87. However, a notable publication surge (84.82%) is observed, particularly from the 21st century onward. The decade from 2010 to 2019 stands out as the most prolific, contributing 71 publications (48.9%), whereas the 1950s and 1960s only yielded one publication. Surprisingly, despite being incomplete and spanning only two years, the last decade boasts nearly the same number of publications as the sum of the 1980s and 1990s and represents over a third of the total publications recorded from 2000 to 2009 (Figure 2).

Figure 2:
Graphical analysis of the relationship between the number of documents published per year and the absolute frequency of the bibliometric review study on the Epidemiology of Scorpionism, covering the period from 1950 to 2022.

Out of 76 sources of information, the highest number of publications throughout the period was from the journal “Toxicon” (25.0%), accounting for a quarter of all publications during this time frame. Following closely was the “Journal of Venomous Animals and Toxins Including Tropical Diseases” (15.8%) (Figure 3). Assessing publications by authors and co-authors, 611 researchers were accounted for, including eight single-author publications. Authors Semlali, I. and Soulaymani, A. demonstrated the highest productivity, contributing to 9 (6.2%) and 7 (4.8%) of the documents published throughout the entire period, respectively. Most of these works originated from Morocco and were published in the “Journal of Venomous Animals and Toxins Including Tropical Diseases.” Notably, no Brazilian author ranked among the top 10 regarding productivity (Figure ). Of the 32 countries examined, Brazil and Iran emerged as the leading producers in scorpionism epidemiology, with 26 documents (17.93%) and 25 documents (17.24%) of the publications, respectively. The combined output of the other major countries, including Morocco, Algeria, Turkey, the United States, France, Egypt, Mexico, and Saudi Arabia, totaled 70 documents (48.27%) published throughout the study period. The top 10 most productive countries collectively accounted for 84% of the publications during the review period (Figure ).

Figure 3:
Network of co-occurrence of words presented in titles, abstracts and keywords, with 1,601 terms and general information (regarding the top 10 journals, authors, countries and affiliations with the highest productivity) of articles published and selected for the bibliometric review study on the Epidemiology of Scorpionism, during the period from 1952 to 2022.

The analysis revealed that universities represented 80% of the affiliations. The Ahvaz Jundishapur University of Medical Sciences, a medical school in the Khuzestan province of Iran, was the leading contributor in terms of production on the subject, with 11 documents (7.5%). In Brazil, the Federal University of Minas Gerais represented 2.7% of the documents (4), securing the ninth position in the ranking of top affiliations (Figure ).

Analysis of frequent terms extracted from text data, as illustrated in Figure 4, displays terms extracted from the titles, abstracts, and keywords of manuscripts published from 1950 to 2022, indicating locations, times of the year, and themes applied by authors. Comprising 1,601 items categorized into 33 clusters, the network features 64,266 links and an edge strength of 92,776. The five most frequently occurring words throughout the study period were “escorpião” (scorpion) with 136 occurrences, “picada” (sting) with 130, “estudo epidemiológico” (epidemiological study) with 114, “estudo de caso” (case study) with 104, and “person” with 90. The prominence of the term “escorpião” highlights its significance in the literature as the primary focus of various researchers. Through the analysis of these terms, significant regions of the world are identified concerning the topic, including Brazil (29 occurrences), Iran (25), Morocco (15), Turkey (9), Argentina (6), Mexico (5), Tunisia (5), the United States (4), Colombia (2), and France (2) (Figure 3).

Figure 4:
Co-occurrence network of words presented in titles, abstracts and keywords of published and selected articles, for each decade of the bibliometric review study on the Epidemiology of Scorpionism, from 1980 to 2022. The image refers to: (a ) 1980s-1989, (b) 1990s-1999, (c) 2000s-2009, (d) 2010s-2019 and (e) 2020s-2022.

The top 10 most frequent terms collectively represent approximately 52.8% of the network. The 10 clusters with the highest number of items are color-coded as red (120), green (84), dark blue (82), yellow (80), purple (75), light blue (74), orange (69), brown (64), magenta (64), and pink (60). The three primary clusters address different aspects of scorpionism as follows:

Cluster 1: Concentrates on the geographical distribution, primary months of incidents, scorpionism as a public health issue with high incidence, socioeconomic conditions, anthropogenic factors, and the use of analyses and software.

Cluster 2: Primarily focuses on the results and clinical conditions of individuals affected by scorpion stings.

Cluster 3: Addresses institutions and strategies for monitoring and controlling scorpionism, emphasizing the risk of mortality and morbidity.

Based on the results generated from the co-occurrence networks of terms found in titles, abstracts, and keywords analyzed in each decade, a clear upward trend in the number of terms used is evident, consistently maintaining scorpion, sting, and epidemiological study as the focal points in scorpionism-related research (Figure 4).

The co-word network for the 1980s consisted of 141 terms distributed across 7 clusters, with the most frequent terms being “sting” (8), “scorpion” (7), and “epidemiological study” (5). The top 5 clusters with the highest number of items are color-coded in red (32), green (25), dark blue (25), yellow (18), and purple (16) (Figure 4a).

The co-word network for the 1990s comprises 200 terms distributed among 6 clusters, with the most frequent terms being “scorpion” (7), “sting” (6), and “case study” (6). The top 5 clusters with the highest number of items are color-coded in red (61), green (41), dark blue (32), yellow (27), and purple (23) (Figure4 b).

The co-word network for the 2000s is composed of 592 terms spread across 19 clusters, with the most frequent terms being “scorpion” (38), “sting” (34), and “epidemiological study” (30). The top 5 clusters with the highest number of items are color-coded in red (44), green (44), dark blue (42), yellow (41), and purple (39) (Figure 4c).

The co-word network for the 2010s comprises 1033 terms distributed among 23 clusters, with the most frequent terms being “scorpion” (68), “sting” (67), and “epidemiological study” (61). The top 5 clusters with the highest number of items are color-coded in red (81), green (71), dark blue (66), yellow (66), and purple (64) (Figure 4d).

The co-word network for the 2020s consists of 321 terms distributed across 11 clusters, with the most frequent terms being “scorpion” (14), “sting” (12), and “case study” (12). The top 5 clusters with the highest number of items are color-coded in red (39), green (37), dark blue (34), yellow (33), and purple (33) (Figure 4e).

Based on the analysis of collaboration between countries/territories of 145 documents, the collaboration map among countries highlights Brazil as the primary producer and disseminator of scientific content on the topic at hand, closely followed by Iran. Interestingly, the United States and Mexico (11.11%), as well as Canada and Algeria (11.11%), are the countries with the most significant collaborative efforts (Figure 5).

Figure 5:
Map of Collaboration between countries that protect knowledge about the Epidemiology of Scorpionism, extracted from bibliometric analysis, during the period from 1950 to 2022.

This exchange of knowledge involves 17 countries. For instance, Algeria collaborates with Benin and France, Brazil similarly cooperates with Argentina, Spain, and Venezuela, Colombia establishes relations with France and Mexico, and France collaborates with Mali and Mexico. Iran teams up with the United Kingdom, Morocco, and France, while Turkey collaborates with the United States, and the United States also engages with Egypt. Venezuela shares a collaborative relationship with Spain. It is worth noting that all these collaborations occur with a frequency of 1 (5.5%).

According to the analysis of the Most Cited Studies, the study entitled “An epidemiological and clinical study on scorpionism by the Iranian scorpion Hemiscorpius lepturus”, published in 2007, authored by Mohammad H. Pipelzadeh, Amir Jalali, Mohammad Taraz, Roya Pourabbas and Abbas Zaremirakabadi, obtained the highest number of citations (146). Followed by “Epidemiological and clinical characteristics of scorpion envenomation in Tunisia” published in 1982, by authors M. Goyffon, M. Vachon and N. Broglio, with 124 citations, and “Epidemiological and clinical aspects of scorpionism by Tityus trivittatus in Argentina” 2003, published by Adolfo R de Roodt, Susana I Garcı́a, Oscar D Salomón, Liliana Segre, Jorge A Dolab, Raúl F Funes and Ernesto H de Titto, with 111 citations. The result of the analysis of the most cited works throughout the period represented in the figure below by the top 10, had 70% of publications in the source “Toxicon” (Figure 6).

Figure 6:
Analysis graph of the top 10 cited studies on the Epidemiology of Scorpionism, based on bibliometric analysis, referring to the period 1950-2022.

Based on the analysis of data extracted from the reading of 14 articles (9.65%) on scorpion epidemiology and associated environmental, climatic and anthropogenic factors, which were examined proportionally (10% of documents) for each decade, it is evident that the Epidemiological aspects of scorpion sting poisoning in different global settings present standardized patterns (Table 2). Almost all studies (92.8%), except for “Classification of Clinical Consequences of Scorpion Stings: Consensus Development,” which focuses solely on clinical symptoms, emphasize the significance of severe clinical symptoms in children under ten and adults over 60. However, mild cases with more frequent local symptoms than systemic ones predominate across all studies. Most articles (85.7%) categorize clinical symptoms into three stages, while only two (14.3%) divide them into four classes, indicating increasing severity yet not necessarily constituting a progression from one to another (Supplementary Table 3).

The most commonly reported symptoms in stage 1 were pain (60%), erythema, and edema (40%). Symptoms like nausea, vomiting, headache, pallor, hyperthermia, sweating, and restlessness were noted in patients at this stage but were less frequent. Nevertheless, two publications (14.3%) describe case studies with clinical symptoms of severity 2 and 3, and two studies (14.3%) do not mention clinical symptoms resulting from scorpion envenomation (Supplementary Table 3).

The body areas at the highest risk of being affected are the extremities, hands, and feet (85.7%). Some studies indicate equal involvement in these areas (42.85%), while others show a more significant occurrence in the feet (57.14%). One study (7.1%) reports the hands and arms being more affected than the legs, and two studies do not provide this information (14.3%). The clinical symptoms are categorized as follows: I. Mild-characterized by local symptoms (pain, swelling, paresthesia, local sweating); II. Moderate-characterized by local symptoms and systemic manifestations such as sialorrhea, sensation of a foreign body (hair) in the throat, generalized sweating, nausea, vomiting, abdominal pain, tachycardia, tachypnea, mild hypertension, restlessness, drowsiness, ataxia, and priapism; III. Severe-which, in addition to moderate symptoms, include hypertensive encephalopathy with seizures, stupor or coma, myocardial failure, electrocardiographic (ECG) changes in the T wave or ST segment, shock or arrhythmia, pulmonary edema or acute respiratory failure secondary to acute respiratory distress syndrome; symptomatic acute pancreatitis, or hemorrhagic gastric ulcer. The publications introducing the fourth clinical stage describe it as a lethal envenomation or neurotoxic phase, with initial symptoms gradually appearing within two hours after the sting. However, complications always occur after this period, marked by abundant vomiting. The course is characterized by shock with cardiovascular collapse, nuclear edema, respiratory distress, high fever (above 39°C), and coma. The ECG is consistently altered, showing signs of myocardial ischemia, ultimately leading to the individual’s death due to sudden shock deterioration and cardiovascular collapse (Supplementary Table 3).

In the realm of the publications reviewed, 78.5% identified antivenom serum as the treatment administered for scorpion stings, with variations based on the severity of the case. Three of the studies (21.4%) should have addressed this aspect. The warmer and rainier months of the summer season, from June to August, were most frequently reported as the peak periods for scorpion sting incidents. Only the studies in Zimbabwe and Argentina reported the months from October to April as having the highest occurrence, a period considered summer in those countries. The severity distribution by gender was either equivalent or slightly different, with most incidents affecting males (50%), while other studies did not show significant differences between the affected genders (35.7%). Four studies (28.5%) observed a higher incidence among women. Different scorpion genera were identified in the studies, with Tityus, Centruroides, Androctonus, Hottentotta, Odontobuthus, and Mesobuthus being the predominant genera. Three studies (21.4%) did not identify the families or species of the arthropods. The genus Tityus was mentioned in studies published in Brazil, Argentina, and French Guiana (Supplementary Table 3).

From the sample of 14 publications, only one (7.1%) established an association between epidemiological aspects and environmental and climatic factors, titled “Pediatric Scorpion Envenomation in Northern Amazonia: A 16-Year Study on Epidemiological, Environmental, and Clinical Aspects,” conducted in 2020 in French Guiana. The study employed the Autoregressive Integrated Moving Average (ARIMA) model to determine the link between environmental conditions and the number of stings or the overall envenomation percentage per month. The study used univariate analysis with variables such as river water level, river flow rate, absolute variation in river level, precipitation, river level variation, sunlight, and temperature, as well as multivariate analysis using variables such as river water level, river flow rate, precipitation, and river level variation through regression analysis (Supplementary Table 3).

The analysis of publication trends by year and term co-occurrences has revealed a notable increase in publications from 1982 to 2022, particularly after 2000. This surge in interest regarding scorpions and technological processes for antivenom production can be attributed to the health risks posed by scorpions (Chippaux et al., 2020; Silva et al., 2005). Additionally, the World Health Organization (WHO) classifies accidents caused by venomous animals, including scorpions, spiders, and snakes, as Neglected Tropical Diseases (NTDs), owing to their impact on socially vulnerable populations with limited access to essential healthcare services.^[31] These findings suggest that the subject is rapidly expanding, indicating a growing need for research to address its associated challenges and concerns.

The review identified Brazil and Iran as the leading contributors to scientific research on scorpion-related topics, including the prevalence of scorpion genera.^[32,21] Countries located in tropical regions experience a high incidence of scorpion envenomation cases.^[22,33–35] Scorpions are predominantly found in tropical and subtropical zones characterized by high temperatures and humidity.

Iran is home to a wide variety of scorpion species, with different genera and species found throughout the country. It is estimated that Iran hosts scorpions from at least five genera, including Mesobuthus, Compsobuthus, Hottentotta, Orthochirus, Androctonus, and Hemiscorpius. Among these, Hemiscorpius lepturus is particularly significant, as it is one of the main species responsible for stings and envenomations in the country (Radmanesh, 1990). The geographic distribution of these scorpions varies depending on environmental factors such as temperature, humidity, and soil characteristics, which support the survival of these animals. In addition to Hemiscorpius lepturus, other scorpion species such as Androctonus crassicauda, Mesobuthus eupeus, Odontobuthus doriae, Hottentotta saulcyi, Hottentotta schach, Compsobuthus matthiesseni, Orthochirus scrobiculosus, Apistobuthus pterigocercus, and Olivierus caucasicus are also among the leading causes of scorpion envenomations in Iran.^[32,21] These species are found in various regions of the country, often associated with hot and dry climates typical of arid and semi-arid zones.

In Brazil, scorpion envenomation ranks as the second most frequently reported epidemiological condition, with over 140,000 cases reported across the country’s regions in recent years, surpassing snakebite cases.^[36] Brazil is a country with a great diversity of ecosystems, which supports the presence of various scorpion species. These animals are predominantly found in tropical and subtropical regions, such as the North, Northeast, and Southeast, but they are also present in other parts of the country, including urban areas.

The most important species in terms of envenomation in Brazil is Tityus serrulatus, a yellow scorpion known for its highly toxic venom. This species is responsible for the majority of severe scorpionism cases in the country. Tityus serrulatus is primarily found in urban and suburban areas, where the warm and humid conditions favor its proliferation. Other species of the Tityus genus, such as Tityus bahiensis and Tityus stigmurus, are also common and can cause envenomations, although with fewer fatal cases. Scorpionism in Brazil has become a public health concern, particularly due to the rising number of reported cases and the high incidence in urban areas. This trend is attributed to uncontrolled urban growth, which alters the natural habitats of these animals and increases human-scorpion contact. Epidemiological studies indicate that scorpion envenomations are one of the leading causes of incidents involving venomous animals in Brazil, second only to snakebites. In 2019, over 140,000 cases of scorpion stings were recorded in the country, surpassing the number of incidents involving snakes and spiders, according to data from the Notification of Injury Information System (SINAN).

Scorpionism has a significant impact on global health systems, primarily due to the large diversity of venomous scorpions and the high incidence of accidents involving these animals. Scorpion stings are common, especially in rural areas and arid climates, where scorpions find shelter in dark, warm places such as burrows, rocks, and poorly maintained structures. The severity of scorpion envenomations can range from mild to severe, depending on the species, the amount of venom injected, and the victim’s overall health. In some cases, the effects of the venom can be fatal, particularly if there is no quick access to antivenom or proper medical treatment. Additionally, extreme weather conditions and environmental changes can worsen the situation. Human populations in rural areas, who often live in poor infrastructure conditions and have limited access to healthcare services, are the most vulnerable.

Toxicon is a highly relevant scientific journal in the field of studies on toxins derived from animals, plants, and microorganisms. Published by Elsevier since 1962, with Ray Norton as the editor-in-chief, the journal serves as an international platform for disseminating original research, innovative discoveries, and reviews on the properties and effects of natural toxins. With an impact factor of 3.033 in 2020, according to the Journal Citation Reports, Toxicon has become one of the main sources of information for scientists and professionals in the field of toxicology. The journal covers a wide range of topics, including venoms from scorpions, snakes, spiders, and other venomous animals, making it a key reference for studies on scorpionism and its medical and therapeutic implications. Among the most cited and significant articles in the journal are those that address the characterization of specific toxins, the development of antivenoms, and the impact of toxins on various biological systems, which have greatly contributed to the advancement of applied toxicology and the treatment of envenomations.

An analysis of the authorship of publications identified Ilham Semlali as the most prolific author in the field of scorpionism epidemiology. Semlali, affiliated with the Centre Anti venin et pharmacovigilance de Maroc in Agdal Rabat, Morocco, is followed by Abdelmajid Soulaymani from the Université Ibn Tofail, Kenitra, Morocco. The significant contributions of these researchers, demonstrated by the high number of citations in related studies, highlight the importance of collaboration in advancing research in this field. It is noteworthy that only eight researchers are responsible for individual studies, indicating a strong culture of collaboration and a highly cooperative research environment within this scientific domain.

The analysis of scientific publications on scorpionism highlights the importance of universities in both Iran and Brazil as key research centers for advancing knowledge in this field. In Iran, the Ahvaz Jundishapur University of Medical Sciences stands out for its strong contribution to studies on scorpionism, particularly regarding endemic species such as Hemiscorpius lepturus, which causes numerous envenomations in the country. A significant example of this contribution is the study “An Epidemiological and Clinical Study of Scorpionism by the Iranian Scorpion Hemiscorpius lepturus,” published by Pipelzadeh et al., (2007), which has received a high number of citations, demonstrating its impact on the field of toxicology and scorpion envenomation epidemiology in Iran. In Brazil, the Federal University of Minas Gerais ranks ninth among the leading affiliated institutions, also standing out for its relevant scientific research on scorpionism. Although the volume of publications is smaller compared to Iran, Brazil has proven to be an important contributor, with a focus on studies related to urban scorpionism and species responsible for envenomations, such as Tityus serrulatus. Cooperation between researchers from different countries is evident, as many publications, including those on Iranian and Brazilian scorpions, are published in prominent journals like Toxicon, which has served as a key platform for disseminating new findings on venoms and antivenoms, publishing 27 of the most cited manuscripts. These observations emphasize international collaboration and the central role of universities in both Iran and Brazil in generating scientific knowledge on scorpionism, while also highlighting the importance of specialized journals such as Toxicon and the Journal of Venomous Animals and Toxins in disseminating critical discoveries for the treatment and prevention of scorpion envenomations in both countries.

When reviewing the literature on scorpionism epidemiology, certain aspects warrant further investigation, particularly the association between environmental, anthropogenic, and climatic variables that may influence the increasing incidence of scorpion-related diseases over the decades. Additionally, it is crucial to explore other factors that may play a role in the evolutionary patterns of scorpion stings. Another consideration is the methodological limitation related to the number of documents from which metadata was extracted, which necessitates a more comprehensive analysis of the documents retrieved. However, the increase in publications between 1950 and 2022, particularly from 2000 onwards, may reflect the growing global interest in scorpionism due to the rising number of reported cases.

In this proposed article, statistical and mathematical analyses have revealed a progressive trend in scorpionism epidemiology worldwide over the past 70 years, primarily associated with clinical aspects in children. This assertion is substantiated by the increasing publication of articles, especially since 2000. Moreover, this article is a pioneering work in employing bibliometric tools to assess the construction and evolution of scientific production concerning scorpionism. It is worth noting, however, that there needs to be more research productivity concerning environmental, climatic, and anthropogenic factors associated with scorpionism. These factors provide additional insights into these creatures, including their distribution and behavior, crucial for effective prevention and treatment measures. The growing application of bibliometric tools in studies has contributed to the dissemination of knowledge, simultaneously highlighting research efforts and facilitating global access to the work conducted.

Scorpionism in Brazil and Iran is a significant public health issue, impacting various regions of both countries, particularly those that are tropical and subtropical. The distribution of scorpions is closely linked to climatic and environmental conditions such as heat, humidity, and unchecked urbanization. The high incidence of scorpion accidents, combined with increasing urbanization and the growing vulnerability of populations in peripheral areas, underscores the importance of public policies focused on prevention, early diagnosis, and treatment of envenomations, as well as public awareness campaigns. Ongoing research on species distribution and venom effects is crucial for developing more effective control strategies and producing appropriate antivenoms.

This comprehensive review underscores the growing concern over scorpion-related incidents worldwide, reaffirming the imperative need to comprehend the underlying causes and establish new preventive measures and policies to reduce the incidence, prevalence, morbidity, and mortality rates attributable to these venomous arachnids. Given the high occurrence rates of scorpion envenomations and the insights gained from this study, we reiterate the importance of seeking early medical assistance in such cases. This not only helps alleviate the suffering of the affected individuals but also plays a pivotal role in minimizing the overall impact of scorpionism on public health.

This study was financed in part by the Coordination for the Improvement of Higher Education Personnel-Brazil (CAPES)-Financial Code 001.