Scorpion sting envenomation outbreak in Mexico. Strategies for prevention and control.

In Mexico occurs 25% of all worldwide cases of scorpion sting envenomation (SSE). An outbreak of SSE was identified in Villa Unión, Sinaloa, Mexico. The objective of this study is to describe the outbreak, and prevention and control strategies implemented. The design was a cross-sectional study. Eligibility criteria included confirmed cases (n = 425) identified from the date the outbreak was recognized (from November 08, 2023 to July 10, 2023). The cases from Villa Unión (n = 231) were included for the analysis of epidemiological and clinical findings. The research followed the recommendations of the Initiative Reporting of studies Conducted Using Observational Routinely collected Data (RECORD). Of the total cases (n = 425), 398 (93.6%) were from the municipality of Mazatlán, and 231 (58%) were from Villa Unión. The incidence rate was 13.64 per 1000 persons. The average cases per week was 51.5(SD ± 12). The male-to-female ratio was 3:4, the average age was 30.7(SD ± 19) years. Most of cases occurred in the 25-44 age group. The sting occurred mostly inside houses (n = 200, 86.5%). The predominant symptoms were local pain (95.2%), and local paresthesia (75.8%). The Case fatality rate was 0%. Implementation of prevention and control strategies based on field epidemiological research and scientific evidence are necessary to reduce the incidence and prevent fatal complications.

Renal Alterations Induced by the Venom of Colombian Scorpion Centruroides Margaritatus.

BACKGROUND: Scorpion venom causes renal injury and affects vascular ion-channels function. Centruroides margaritatus scorpion is found in Colombia and is frequently the cause of envenomation accidents; however, its renal impact has never been investigated. OBJECTIVE: To evaluate the effects of C. margaritatus venom (CmV) on renal parameters using isolated rat kidney and renal cell culture models. METHODS: Wistar rats (n = 5, weighing 240-300 g) were first perfused with Krebs-Henseleit solution containing 6 g 100 mL-1 bovine serum albumin. After 30 minutes, the kidneys were perfused with CmV to a final concentration of 10 µgmL-1; evaluation was performed by measuring Perfusion Pressure (PP), Renal Vascular Resistance (RVR), Urinary Flow (UF), Glomerular Filtration Rate (GFR), and percentage of electrolyte tubular transport. Moreover, kidney histological analyses and cell cytotoxicity in renal tubule epithelial cells (MDCK) and proximal tubular cells (LLC-MK2) were assessed. RESULTS: CmV increased PP and RVR 60 min after perfusion. On the other hand, UF, GFR, and the percentages of sodium, potassium and chloride tubular transport decreased after experimental envenomation. UF dropped after 120 min, while GFR and percentage of electrolyte tubular transport diminished after 60, 90 and 120 min. CmV was not toxic to MDCK cell line but reduced the viability of LLC-MK2 cells at concentrations ranging from 6.25 to 200 µgmL-1. Histological analyses disclosed hydropic degeneration, edema, and protein deposits. Flow cytometry disclosed that cell death occurred predominantly by necrosis. CONCLUSION: Our results suggest that C. margaritatus venom can trigger renal impairment, mainly in the proximal kidney tubule.

EP80317 Restrains Inflammation and Mortality Caused by Scorpion Envenomation in Mice.

Over 1 million cases of scorpion stings are estimated every year, whereas current treatment is limited to antivenom serum combined with supportive therapy. Tityus serrulatus scorpion venom (TsV) is composed of diverse molecules, including toxins that induce a catecholamine storm and mediate classical symptoms of scorpion envenomation. However, the same toxins promote an intense inflammatory response coordinated by innate immune cells, such as macrophages, contributing significantly to the lung edema and mortality caused by TsV injection. Macrophages sense TsV via innate immune receptors, including TLR2, TLR4, and CD14 that promote inflammation and mortality via PGE2/cAMP/PKA/NF-κB/IL-1ß axis. The scavenger receptor CD36 also recognizes TsV, but in contrast to the other receptors, it drives the production of leukotriene B4 (LTB4). This lipid mediator operates via BLT1 receptor to reduce cAMP production and consequently IL-1ß release, which results in resistance to fatal outcomes of experimental scorpion envenomation. EP80317 is an hexapeptide that serves as a ligand for CD36 and features protective effects under conditions such as atherosclerosis and vascular inflammation. In this study, we evaluated the effects of EP80317 treatment during experimental scorpion envenomation. EP80317 treatment suppressed mouse peritoneal macrophage production of IL-1ß, IL-6, tumor necrosis factor (TNF-α), CCL3, and PGE2 in vitro. EP80317 treatment also boosted the production of LTB4 and IL-10 in response to TsV. Importantly, EP80317 restrained lung inflammation and mortality caused by TsV in vivo. Taken together, these data indicate a strong therapeutic potential of EP80317 as a supportive treatment to control inflammation induced by scorpion envenomation.

Malnutrition alters the cardiovascular responses induced by central injection of tityustoxin in Fischer rats.

Scorpion envenoming and malnutrition are considered two important public health problems in Brazil, involving mainly children. Both these conditions are more common among the economically stratified lower income portion of the population, thus suggesting that these factors should be analyzed concomitantly. It is known that cardiorespiratory manifestations, as cardiac arrhythmias, arterial hypertension and hypotension, pulmonary edema and circulatory failure are the main "causa mortis" of scorpion envenomation. Additionally, there are evidences in the literature that deficiencies in dietary intake endanger the CNS and modify the cardiovascular homeostasis. Then, the objective of this work is to evaluate the protein malnourished effect on cardiovascular responses induced by tityustoxin (TsTX, an α-type toxin extracted from the Tityus serrulatus scorpion venom). Fischer rats (n = 20) were injected i.c.v. with TsTX and divided in control and malnorished groups, which were, respectively, submitted to a control and a low-protein diet. Arterial pressure recordings were done until death of the animals. Although both groups presented an increased mean arterial pressure after TsTX injection, this increase was smaller and delayed in malnourished rats, when compared to control rats. In addition, heart rate increased only in rats from the control group. Finally, malnourished rats had an increase in survival time (9:9/13.5 vs. 15.5:10.5/18 min; p = 0.0009). In summary, our results suggest that the protein restriction attenuates the cardiovascular manifestations resulting from TsTX action on CNS.

Echocardiographic changes during acute pulmonary edema subsequent to scorpion sting

Acute pulmonary edema (APE) occurring after scorpion sting is the leading cause of death of the victims of scorpion envenomation. The APE origin is still questioned by physicians treating these patients. Based on echocardiographic study of 20 patients with severe envenomation treated in Ouargla Hospital resuscitation ward during the last four years, the APE etiology seems more likely cardiogenic, referring to cardiac symptoms confirmed by echocardiography although other mechanisms may also be involved. This hypothesis is further confirmed by the positive response of patients to the administration of dobutamine.(AU)

Echocardiographic changes during acute pulmonary edema subsequent to scorpion sting

Acute pulmonary edema (APE) occurring after scorpion sting is the leading cause of death of the victims of scorpion envenomation. The APE origin is still questioned by physicians treating these patients. Based on echocardiographic study of 20 patients with severe envenomation treated in Ouargla Hospital resuscitation ward during the last four years, the APE etiology seems more likely cardiogenic, referring to cardiac symptoms confirmed by echocardiography although other mechanisms may also be involved. This hypothesis is further confirmed by the positive response of patients to the administration of dobutamine.(AU)

Envenamiento escorpiónico en El Palmar: estado Bolívar, Venezuela / Scorpion envenomation in El Palmar: state of Bolívar, Venezuela

Se determinó la prevalencia del envenenamiento escorpiónico en el Palmar-Edo. Bolívar durante el período comprendido entre enero 2005 y enero 2007. Hubo un total de 9 casos de escorpionismo (0,75 casos/1000 habitantes), afectando principalmente los miembros superiores de varones menores de 30 años, estudiantes, procedentes de zonas rurales. Los casos registrados ocurrieron durante el período lluvioso, entre los meses de abril y agosto. No se registraron casos mortales. Los hallazgos indican una casuística no despreciable de envenenamiento escorpiónico leve, sugiriendo la posible existencia de escorpiones poco tóxicos en la localidad estudiada

The prevalence of scorpion envenomation in El Palmar, State of Bolivar, was determined from January 2005 to January 2007. There were 9 cases of scorpion envenomation (0.75 cases/1000 inhabitants), affecting mainly the superior members of male students less than 30 years old that came from rural regions. Registered cases occurred in the rainy season between April and August. No fatalities were registered. Findings indicate a non-negligible prevalence of trivial scorpion envenomation, suggesting the possible existence of low toxicity scorpions in the locality under study

Análise de variáveis relacionadas à evolução letal do escorpionismo em crianças e adolescentes no estado de Minas Gerais no período de 2001 a 2005 / Analysis of variables related to fatal outcomes of scorpion envenomation in children and adolescents in the state of Minas Gerais, Brazil, from 2001 to 2005

OBJETIVOS: Descrever e avaliar os acidentes escorpiônicos notificados no estado de Minas Gerais, em crianças e adolescentes, no período de 2001 a 2005, e calcular incidência e mortalidade e identificar fatores relacionados à evolução para óbito. MÉTODOS: Estudo de 14.406 fichas de notificação obrigatória do escorpionismo em Minas Gerais, de pacientes de 0 a 19 anos. Após análise univariada, com fatores relacionados a mortalidade (p < 0,25), foi realizada regressão logística para análise multivariada. RESULTADOS: Houve aumento das notificações dos acidentes escorpiônicos ao longo dos anos. A faixa etária em que mais ocorreu acidente foi de 5 a 9 anos. Dor local esteve presente em 95 por cento dos casos. A maioria dos casos foi classificada como leve (60 por cento), com utilização do soro em 42 por cento dessa população. A letalidade média foi de 0,7 por cento. O município de maior ocorrência do acidente foi a capital Belo Horizonte. O atraso de cada 1 hora até o primeiro atendimento representou aumento de 9 por cento na razão de chance de evolução para óbito, que foi 46 vezes maior no grupo grave do que nos grupos moderado e leve. Para cada ano a menos na idade do paciente houve um aumento de 13 por cento na razão de chance de evolução para óbito. CONCLUSÕES: Houve aumento do número de notificações ao longo dos anos estudados. Foram identificados como fatores com maior razão de chance de evoluir para óbito: atraso para o primeiro atendimento, ser classificado como grave e menor idade.

OBJECTIVES: To describe and evaluate notified scorpion envenomation incidents in children and adolescents in the Brazilian state of Minas Gerais between 2001 and 2005, and to calculate the incidence and mortality and identify factors related to fatal outcomes. METHODS: Analysis of 14,406 mandatory notifications of scorpion envenomation involving patients aged 0 to 19 years in Minas Gerais. After performing a univariate analysis of factors related to mortality (p < 0.25), multivariate analysis was carried out using logistic regression. RESULTS: The number of notifications of accidents involving scorpions increased over the period. The age group that suffered most accidents was 5 to 9 years. Local pain was reported in 95 percent of cases. The majority of cases were classified as mild (60 percent) and antivenom was given to 42 percent of this population. The mean mortality rate was 0.7 percent. The state capital, Belo Horizonte, was the municipality with the greatest occurrence of incidents. Each hour's delay before receiving first medical care was associated with a 9 percent increase in the odds ratio for the likelihood of death, which was 46 times greater in the severe group than in the moderate and mild groups. A decrease of 1 year in patient age was associated with a 13 percent increase in the odds ratio for the likelihood of death. CONCLUSIONS: There was an increase in the number of notifications over the period studied. The following factors were identified as linked with a higher odds ratio for the likelihood of death: delayed first medical care, being classified as a severe case, and younger age of victim.

Epidemiological study of scorpion stings in Saudi Arabia between 1993 and 1997

This investigation evaluated the epidemiological aspects of scorpion stings in different areas of Saudi Arabia. A total of 72,168 cases of scorpion stings recorded in Ministry of Health Medical Centers in 11 selected areas of Saudi Arabia were analyzed based on area, age, sex, time of sting, sting site, treatment outcome, time of year, and scorpion species. Stings occurred throughout the year; the highest frequency was in June (15.08%), the lowest in February (2.52%). Most patients were male (61.8%); the majority of which were more than 15 years old (65.4%). Nocturnal envenomation (47.74%) was more common than diurnal (43.91%); most stings were in exposed limbs (90.95%), mainly in the lower limbs (63%). Most envenomings were mild (74.48%) and all evolved to cure, except for one death. Envenomation was characterized by local pain, erythema, headache, vomiting, and anxiety. This study found that the Leiurus quinquestriatus (Ehrenberg 1828), Androctonus crassicauda (Olivier 1807), and Apistobuthus pterygocercus (Finnegan 1807) were responsible for most of the stings, indicating their medical importance in Saudi Arabia. The study shows low threat to life despite the high number of stings; this is a result of the availability of medical facilities and the multi-center antivenom use in different areas of Saudi Arabia.

Epidemiological study of scorpion stings in Saudi Arabia between 1993 and 1997

This investigation evaluated the epidemiological aspects of scorpion stings in different areas of Saudi Arabia. A total of 72,168 cases of scorpion stings recorded in Ministry of Health Medical Centers in 11 selected areas of Saudi Arabia were analyzed based on area, age, sex, time of sting, sting site, treatment outcome, time of year, and scorpion species. Stings occurred throughout the year; the highest frequency was in June (15.08%), the lowest in February (2.52%). Most patients were male (61.8%); the majority of which were more than 15 years old (65.4%). Nocturnal envenomation (47.74%) was more common than diurnal (43.91%); most stings were in exposed limbs (90.95%), mainly in the lower limbs (63%). Most envenomings were mild (74.48%) and all evolved to cure, except for one death. Envenomation was characterized by local pain, erythema, headache, vomiting, and anxiety. This study found that the Leiurus quinquestriatus (Ehrenberg 1828), Androctonus crassicauda (Olivier 1807), and Apistobuthus pterygocercus (Finnegan 1807) were responsible for most of the stings, indicating their medical importance in Saudi Arabia. The study shows low threat to life despite the high number of stings; this is a result of the availability of medical facilities and the multi-center antivenom use in different areas of Saudi Arabia.

THE MOUSE AS AN EXPERIMENTAL MODEL FOR TITYUS SERRULATUS SCORPION ENVENOMING

The scorpion toxin induces a number of physiological parameters alterations, as disturbance of cardiac rhythm, heart failure, shock, pancreatic hypersecretion, abortion, respiratory arrhytmias and pulmonary edema. As the purification of the venom fractions is a laborious process, one alternative for this would be the utilization of small animals. We utilized in the present study thity-six mice that received progressive doses of scorpion toxin TsTX), i.p. or i.v., and were observed for three hours or sacrificed, and the pulmonary alterations were determined by the lung-body index and by histological analysis of the lungs in order to determine if the mouse can be an esperimental model for scorpion envenomation. The data were analyzed by One Way analysis of variance with p 0,05 indicating significance. These experiments showed no differences in clinical signs of scorpion envenomation between mice and other mammalians, the effects were dose-dependent and the i.v. administration needed less quantity to produce the same changings. In the pulmonary histology we observed septal but not alveolar edema, and we presumed that these differences are due to species-specific variations.

A toxina do escorpião induz a várias alterações fisiológicas, como disturbio do ritmo cardíaco, insuficiência cardíaca, choque, hipersecreção pancreática, aborto, arritmias respiratórias e edema pulmonar. A purificação de frações do veneno é um processo trabalhoso. Como alternativa utilizam-se animais pequenos. No presente estudo utilizou-se 36 camundongos que receberam doses progressivas de toxinas do escorpião (TsTX), intraperitoneal ou intravenosa e foram observados por tres horas ou sacrificados. As alteraçòes pulmonares foram determinadas pela fórmula peso do pulmão x 100/ peso corporal e pela análise hitológica dos pulmões a fim de determinar que o camundongo pode ser um modelo experimental do envenenamento pelo escorpião. Os dados foram analizados pela análise de variância considerando-se p 0,05 indicando significancia. Os experimentos não mostraram diferença nos sinais clínicos do envenenamento comparando-se o camundongo com outros mamíferos. Os efeitos foram dose-dependente e que pela via venosa necessita-se menos quantidade para produzir as mesmas alterações. Nos aspectos histológicos pulmonares observou-se edema septal e não alveolar. Presume-se que as diferenças observadas são devidas a variações específicas das espécies.