Scorpionism in Ecuador - An updated review

 

Scorpion envenomations are a problem in many countries in South America, but a majority of studies have focused on Brazil. A recent article by Adolfo Borges and co-workers shows that also Ecuador is a hotspot for scorpion envenomations in South America.

The study provides an overview of scorpion stings in Ecuador between 2017 and 2021 and the implications in form of deaths and morbidity. The authors also identify taxa of medical importance and their distribution. Unsurprisingly, two species in the genus Tityus C. L. Koch, 1836 (Buthidae) are probably responsible for the most serious cases.  

Abstract:
This study assessed scorpion envenoming risk in Ecuador at provincial and district levels between 2017 and 2021, estimated national incidence and mortality rates, and identified the likely implicated taxa. Data were obtained from the Ministry of Public Health and aggregated by province and district, with incidence and mortality rates calculated per 100,000 inhabitants using annual population estimates. District-level risk was visualized with choropleth maps, and scorpion diversity and distribution were compiled from updated national inventories. A total of 1,514 scorpion stings were reported between 2017 and 2021. National incidence and mortality rates (per 100,000 inhabitants) averaged 1.75 and 0.02. Regional incidence was highest in the Amazonian region (16.81), followed by the coastal (1.39) and Andean highlands (0.66). Hyperendemic districts (≥95th percentile of risk) included Taisha and Tiwintza (Morona Santiago), Arajuno (Pastaza), Flavio Alfaro (Manabí), and La Concordia (Santo Domingo de los Tsáchilas). Mortality was highest in the Amazonian and piedmont coastal regions, with 10 deaths per region and an Amazonian rate of 0.44 per 100,000 inhabitants. These areas are inhabited by Tityus species from distinct morphological and toxinological groups, notably Tityus cf. rosenbergi in western Ecuador and Tityus cisandinus in Morona Santiago and Pastaza. Geographical variation in incidence and mortality likely reflects both the distribution of noxious taxa and population density. Despite high scorpion endemicity (79.2%), a national lethality rate of 1.32% that appears higher than reported in other countries where scorpionism is a public health concern, and the concentration of fatalities in children (75% in ages 1–9), Ecuador still depends on imported scorpion antivenoms, including that prepared against Centruroides species, which show low reactivity to Tityus toxins. These findings highlight the urgent need for preclinical neutralization studies to evaluate local antivenom efficacy and to investigate regional differences in clinical outcomes, to guide future adjustments to immunotherapy based on the biogeographic distribution of medically important Tityus species.

Reference:
Borges A, De Sousa L, Borja-Cabrera GP, Rivera A. Scorpion Envenoming in Ecuador: District-Level Risk, Updated Scorpion Diversity, and Challenges for Treatment and Public Health. Acta Trop. 2025:107942 (In Press). [Subscription required for full text.]

Thanks to Adolfo Borges for informing me about their new article! 

Are scorpion envenomations a neglected tropical disease?

 

For us who work or have experiences with scorpions, it is well known that some genera and species can cause death and serious morbidity in humans. This is a problem in some countries and regions in the world.

Eduardo Alfonso Hernández Muñoz and co-workers recently published an article summing up the status of scorpionism globally and raise a concern that scorpion envenomations are not given priority as a serious tropical disease today. According to the authors, the serious consequences from scorpion stings in many areas of the world should support that scorpion sting envenomations should be given a status as a neglected tropical disease by health authorities. This will hopefully increase the focus on prevention and treatment of scorpion envenomations.

That article present a table with list of countries and taxa that have potential medical importance.

Abstract:
⇒Each year, scorpion sting envenomation (SSE) leads to thousands of deaths and severe complications, disproportionately affecting vulnerable populations with limited access to timely treatment, especially children under 10 years of age; however, it is not formally recognised by the WHO as a neglected tropical disease (NTD).

⇒ In 2018, the WHO concluded that SSE did not meet the NTD criteria, citing ‘extremely rare mortality, lack of long-term disability and difficulties in defining a broad control strategy’.

⇒ This analysis presents evidence-based arguments for the urgent reconsideration of SSE as an NTD, considering new data that addresses previous objections and underscores its significant and underestimated public health impact.

⇒ Addressing SSE as an NTD is a crucial step towards achieving global health equity and preventing avoidable deaths in vulnerable communities, particularly among children.

Reference:
Hernández Muñoz EA, Borges A, Zavala-Sánchez EV, Rojas de Arias A, Oukkache N, de Souza CMV, et al. Scorpion sting envenomation: a neglected tropical disease in the shadow of global health priorities: an urgent call to action. BMJ Glob Health. 2025;10(11):e020682. [Open Access]

Thanks to Dr. Adolfo Borges for sending me their article!

A study of circadian rhythms in two species of cave-dwelling Troglorhopalurus species in Brazil

 

Circadian rhythms are important for all animals including humans in governing the organisms daily activities when it comes to both physiology and activity. These rhythms are controlled by a biological clock that usually are adjusted by external stimuli like light and dark.

Cave-dwelling scorpions like members of the genus Troglorhopalurus Lourenço, Baptista & Giupponi, 2004 (Buthidae) are more or less living in the dark permanently. Priscila Emanuela de Souza and Rodrigo Lopes Ferreira have recently published an article studying locomotor behavior in two species of Troglorhopalurus when exposed to different light-dark regimes. 

Interestingly, their study show that both species were able to retain their normal circadian rhythmicity in all regimes (they were able to "keep the time"), even though this varied between the two species. This can be explained by the different degree of adaptation to cave habitats seen in the two species.

Abstract:
Circadian rhythms, typically synchronized with light–dark cycles, regulate key biological processes in surface organisms. In caves, however, the absence of light may disrupt these rhythms or promote alternative temporal patterns. We examined locomotor activity in two cave-dwelling scorpions with contrasting degrees of subterranean adaptation: Troglorhopalurus translucidus (troglobitic) and Troglorhopalurus lacrau (troglophilic). Activity was monitored under constant darkness (DD), light–dark (LD), and constant light (LL). Both species retained circadian rhythmicity, but with distinct responses: T. translucidus and T. lacrau exhibited diurnal activity under LD and changes in period under DD and LL. These findings demonstrate that circadian regulation persists in cave adapted scorpions, but its expression is shaped by evolutionary pressures, highlighting the plasticity of biological clocks in light-deprived environments.

Reference:
de Souza PE, Ferreira RL. Oscillating in darkness: Circadian rhythms of cave-dwelling scorpions. Chronobiol Int. 2025:1–8. [Subscription required for full text]

An updated look at scorpion envenomations in Namibia

 

Scorpion envenomations and their medical importance in Namibia have been underreported and neglected. Namibia is the home for several Parabuthus Pocock, 1890 (Buthidae) species, a genus known for hosting several species of medical importance.

Francois Theart and co-workers recently published an article with updated information about scorpionism in Namibia. They conclude that scorpions are a health concern in this country and especially the species Parabuthus granulatus (Ehrenberg, 1831), P. villosus (Peters, 1862), kraepelini Werner, 1902 and P. schlechteri Purcell, 1899 can cause death and serious morbidity. No antivenom is available. More research is necessary to understand more about the situation and to develop measures to improve prevention and treatment.

Abstract:
Namibia harbours a rich diversity of scorpions, including seventeen species of the highly venomous genus Parabuthus, although the biology and medical relevance of most species are poorly documented. Severe envenoming is caused by at least P. granulatus, P. villosus, P. kraepelini and P. schlechteri, which are considered to be of particular importance. Data on epidemiology, venom composition and variation, and clinical effects remain scarce. A lack of effective antivenom and long distances to hospitals in rural areas complicate clinical management and compromise patient outcomes.

Reference:
Theart F, Buys C, Lagneau S, Berg P. Scorpion envenoming by Parabuthus is a public health concern in Namibia. Toxicon. 2025;270:108934. [Subscription required for full text]

On the occurence of the medically important scorpion Tityus stigmurus in the São Paulo area in Brazil

 

As mentioned in several other posts, the expanding distribution of medical important Tityus C. L. Koch, 1836 (Buthidae) species in Brazil and other South American countries has had an increasing attention, especially because many of these species are also spreading into urban habitats.

Paulo Goldoni and co-workers have recently published an article looking into the distribution of the medically important scorpion Tityus stigmurus Kraepelin, 1898 (Buthidae) in the municipality of Sorocaba, São Paulo in Brazil. The study conforms that this species is introduced and successfully established on this area.

Abstract:
Tityus stigmurus (Thorell, 1876) is among the most venomous scorpion species in Brazil. It occurs mainly in the northeastern region, particularly within the Caatinga biome, where it represents a major public health concern, with several fatal envenomation cases reported. The species has also been recorded as introduced in urban areas of São Paulo, confirming its establishment in a colder and more humid environment than its native range in the country. During the 2010s and 2020s, records of T. stigmurus were also reported from Sorocaba, about 100 km from São Paulo city. Here, we confirm the successful establishment of the species in Sorocaba, based on 53 examined specimens (41 females and 12 juveniles) collected between 1997 and 2025 and deposited in the arachnid collection of the Instituto Butantan (IBSP). Although no envenomation cases have been reported for this species in the municipality, our findings underscore the need for strengthened surveillance of T. stigmurus in Sorocaba and surrounding areas, as this and other Tityus species already confirmed in the region represent a major public health concern.

Reference:
Goldoni PA, Ennser JRP, Iniesta LF, Brescovit AD. Long-term surveillance and monitoring of Tityus stigmurus (Thorell, 1876): a study in the municipality of Sorocaba, São Paulo, Brazil. Studies in Environmental and Animal Sciences. 2025;6(3):e21937.

Thanks to Paulo Goldoni for sending me their article!

 

A new species of Androctonus from Saudi Arabia

 

Ersen Yagmur and co-workers recently described a new species of Androctonus Ehrenberg, 1828 (Buthidae) from Najd Plateau of Saudi Arabia.

Androctonus najdensis Yagmur, Alqahtani & Badry, 2025 

The article also provides an identification key for the genus Androctonus in the Middle East, Turkey, and Iran.

Abstract:
A new scorpion species, Androctonus najdensis sp. nov., is described and illustrated from Saudi Arabia. It is compared with existing species from the Middle East and Iran, notably A. crassicauda (Olivier, 1807) and the recently described A. tihamicus Alqahtani, Yağmur & Badry, 2023. Molecular analysis using the COI mitochondrial gene revealed a genetic divergence of 7.0 to 11% between A. najdensis sp. nov. and A. crassicauda sensu lato samples from Saudi Arabia, Iraq, and Iran. The combination of molecular and morphological data supports the recognition of the Najd populations as a distinct species. Additionally, an identification key for Androctonus species in Iran and the Middle East is provided.

Reference:
Yagmur EA, Alqahtani AR, Badry A. A new species of Androctonus from the Najd Plateau of Saudi Arabia (Scorpiones, Buthidae). ZooKeys. 2025(1262):33–59. [Open Access]

Thanks to Ersen Yagmur, Gerard Dupre and Matt Simon for all sending me a link to this new article! It is easy to stay updated with so much great help from all of you! :)

Family Buthidae 

New study on the Buthus species in Tunisia with the description of a new species

 

Sarra Hajri and co-workers have recently published an article looking into the genetics and morphology of the known species Buthus Leach, 1815 (Buthidae) in Tunisia. Most known species are confirmed and a new species is described from the country.

Buthus saidnouirai Hajri, Bahri & Harris, 2025 

Abstract:
The taxonomy of the scorpion genus Buthus is complex due to the considerable increase in newly reported species, their high degree of similarity, and consequently, the great difficulty in their morphological differentiation. Tunisian species are not exempt from this issue, with several references highlighting the need for taxonomic revisions. This study integrates DNA sequence data and morphological assessments to investigate the diversity present in Tunisia and to provide morphological details that facilitate species identification. The results show that most Tunisian specimens are distributed within two clades. One clade comprises four subclades corresponding to B. tunetanus Herbst, 1800, B. paris C. L. Koch, 1839, B. chambiensis Kovařík 2006 and a southern group corresponding probably to B. lourencoi Rossi, Tropea & Yağmur, 2013. The second clade represents a new species described in this study as B. saidnouirai Hajri, Bahri & Harris, sp. nov. No evidence of B. dunlopi Kovařík 2006 have been recorded in the studied samples. Distances between all five species exceed the minimum divergence thresholds for Buthus species. The greatest distance was observed between B. saidnouirai. sp. nov. and the southern group, while the smallest distance was between B. tunetanus and B. paris. Although the genetic differences revealed considerable divergence of the new group from the four remaining species, the morphological assessment did not identify the same pattern. These five species demonstrate a morphological shape gradient in which B. paris and the southern group represent the two extremes, with B. paris being the most ornamented and the latter the least. The new species presents an intermediate morphology. The geographic distributions of the five reported species are discussed in this work according to the topography and orography of the region. Additional lineages known from Algeria may also enter the western fringes of Tunisia.

Reference:
Hajri S, Bahri L, Harris DJ. New Insights on Genetic and Morphological Divergence Among a Buthus Species Complex From Tunisia With the Identification of a New Species. Ecology and evolution. 2025;15(12):e72556. [Open Access]

Thanks to Gerard for sending me this article!

Family Buthidae