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Envenomation by scorpions of the genus Tityus is an important public health problem in Argentina, involving near 8000 stings and 2 deaths each year. Treatment for envenomation is the use of specific antivenom and intensive hospital care. Antivenom is produced by the Ministry of Health and freely distributed throughout the country. For antivenom production it is necessary to collect scorpion venom, which is a difficult task because although scorpions can be found in Argentina, they are less abundant than in warmer latitudes. For this reason venom collection constitutes a bottleneck for antivenom production. Although in Argentina several species of Tityus can be found, most of the accidents are caused by Tityus trivittatus, and the venom of this scorpion has historically been the venom used for antivenom production. We analyzed retrospectively 26 pools of telson homogenates (6964 telsons) and 37 pools of milked venom obtained by electrical stimulation (equivalent to 6841 milkings). Lethal potencies of samples from different provinces were very similar, although venom from scorpions of Buenos Aires city showed the lowest potency. The venom obtained by milking (median LD50 12.3 µg), provided batches containing LD50s more potent when compared with the venom obtained from telson homogenates (p < 0.0001). Many batches of telson homogenates (30%) showed lower potencies than acceptable for antivenom production and control. In addition to the study of the venom yield, the records of immunization of horses, the potency of the batches and the protein content of each batch of anti-scorpion antivenom produced were analyzed, comparing those produced using milked venom with those using telson homogenates as immunogens. Batches produced using milked venom required a shorter period of immunization (p < 0.0001), rendered higher neutralizing titers (p 0.0350) and possessed lower protein content (p 0.0092). Results clearly showed that the milking of scorpions is a more efficient tool to obtain venom for antivenom production in comparison to the use of telson homogenates.

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En Argentina los accidentes causados por animales venenosos constituyen un problema de salud pública. En este estudio analizamos los accidentes y muertes por envenenamientos por mordedura o picadura de serpientes, escorpiones y arañas, y las muertes causadas por abejas- avispas-avispones, centípedos, animales marinos, otros artrópodos y otros animales venenosos en Argentina, recibidos por las autoridades sanitarias nacionales. Se analizó la información sobre accidentes y muertes producidas por este tipo de animales que fueron recibidas por el Ministerio de Salud de la Nación durante el período 2000-2011. Debido al tipo de sistema de notificación solo se pudieron calcular tasas de morbilidad y letalidad en los accidentes por arañas, escorpiones y serpientes. Contrariamente a lo que se suponía, no fueron estos los grupos que mayor cantidad de muertes causaron en el período de estudio, sino los himenópteros (abejas-avispas- avispones). El actual esquema de notificación de envenenamiento por animales venenosos provee información importante para el sistema sanitario. Sin embargo, deben realizarse modificaciones a fin de mejorar el conocimiento epidemiológico referente a envenenamientos por la mordedura o picadura de animales venenosos. De esta manera, se podrá progresar en la implementación de las medidas de prevención de estas patologías, su atención a nivel del primer nivel asistencial y la planificación de la producción de antivenenos.

In Argentina, accidents by venomous animals are a problem of public health. In this study we analyzed the envenomation caused by the bite or sting of snakes, scorpions and spiders and the deaths produced by the envenomation caused by this animals and the deaths caused by bees-wasp-hornet, centipedes, marine animals, other arthropods and other venomous animals in Argentina, recorded by the National Ministry of Health in the period 2000 ­ 2011. Most of the accidents were caused by scorpions nevertheless the highest lethality was observed in snakebites envenomation. Contrary to the general suppositions, hymenoptera (bee-wasp- hornet) were the responsible for the highest number of deaths. The present system of information of envenomation by venomous animals gives important information. However some modifications should be done to achieve a best knowledge of the epidemiological situation of the envenomation caused by bites or sting of the different venomous animals, in order to improve the prevention measures as well as the attention at the first level of sanitary assistance and the planning of antivenom production.

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"Black widow" spiders belong to the genus Latrodectus and are one of the few spiders in the world whose bite can cause severe envenomation in humans and domestic animals. In Argentina, these spiders are distributed throughout the country and are responsible for the highest number of bites by spiders of toxicological sanitary interest. Here, we studied the toxicity and some biochemical and immunochemical characteristics of eighteen venom samples from Latrodectus spiders from eight different provinces of Argentina, and the neutralization of some of these samples by two therapeutic antivenoms used in the country for the treatment of envenomation and by a anti-Latrodectus antivenom prepared against the venom of Latrodectus mactans from Mexico. We observed important toxicity in all the samples studied and a variation in the toxicity of samples, even in those from the same region and province and even in the same Latrodectus species from the same region. The therapeutic antivenoms efficiently neutralized all the venoms studied.

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Although the spiders of the genus Phoneutria cause envenomation and their presence has been described in several provinces of the north of Argentina, they are not as common as other spiders of sanitary importance. In the present work, we studied the toxicity of samples of venom of Phoneutria spiders from the provinces of Misiones (where severe envenomation and deaths by Phoneutria have been recorded) and Jujuy (where no deaths have been recorded and severe envenomations are not frequent). To this end, we assessed the lethal potency in mice and guinea pigs and the histopathological alterations caused by both venoms, as well as the neutralization by the commonly used therapeutic antivenom produced by the Butantan Institute in Brazil and by an experimental antivenom developed with venom of P. nigriventer from Misiones. There were no differences in the lethality of the venoms of spiders from both regions. Post mortem examination showed that the heart and lungs were the most affected organs, while important pulmonary edema was seen macroscopically. Histological analysis showed edema, atelectasis, emphysema and cardiac lesion in both experimental models. The antivenoms assayed showed good neutralization of the venoms in the two experimental models. Despite the different geographic origins, the venoms showed similar toxicity and both the experimental antivenom and therapeutic antivenmos were able to neutralize the venoms of Argentinean P. nigriventer.

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. Los escorpiones de importancia médica en el mundo pertenecen mayoritariamente a la familia Buthidae. En Argentina, los miembros de esta familia no son numerosos, siendo mucho mayor el número de especies de la familia Bothriuridae, cuyos miembros hasta el momento no revisten importancia médica. Dentro de los tres géneros de Buthidae que viven en el país, el género Tityus es el que posee especies cuya picadura e inoculación de veneno puede provocar accidentes severos. En general, la diferenciación entre Tityus trivittatus, el escorpión de mayor importancia médica de Argentina, respecto a otros escorpiones, es fácil en las provincias de la zona central del país. Sin embargo, las reglas a utilizar para la diferenciación entre escorpiones de importancia médica de aquellos que no la tienen, no son similares en todo el país. En esta actualización, se brindan elementos sencillos y claros para que el personal de salud pueda diferenciar entre las especies de Tityus de importancia médica de los escorpiones de la familia Bothriuridae, ampliamente distribuidos en la superficie del país. De esta forma, se espera que el diag¡nóstico acertado sobre la especie de escorpión pueda mejorar la atención en el caso de la picadura por animales potencialmente peligrosos. Por otro lado, permitirá diferenciar a los escorpiones sin importancia médica lo que redundará en la mejor utilización de los recursos disponibles en los niveles de atención primaria, ante la emergencia que representa una picadura de alacrán.(AU)

The scorpions of medical importance in the world mostly belong to Buthidae family. In Argentina, members of this family are not numerous, being much most numerous the species from the Bothriuridae family, whose members so far are of no medical importance. Within the three genera of Buthidae that inhabit in the country, only species from Tityus genus can cause severe ac¡cidents. The differentiation between the scorpions of highest medical importance in Argentina (Tityus trivittatus), regarding other scorpions, is easy in the provinces of the central region. However, the rules used for the differentiation of medically important scorpions regarding those not dangerous, is not similar through the country. In this update, we provide simple and clear tools for the health personnel to differentiate between species of Tityus with medical importance and the scorpions from Bothriuridae fam¡ily, widely distributed in the country. Thus it is expected that the accurate diagnosis of the species of scorpions may improve the attention in the case of the sting of potentially dangerous scorpions. On the other hand, the differentiation of the not dangerous scorpions from those with medical importance will result in the best use of the available resources in primary care level, consider¡ing the emergency that represents a scorpion sting.(AU)

RESUMEN

. Los escorpiones de importancia médica en el mundo pertenecen mayoritariamente a la familia Buthidae. En Argentina, los miembros de esta familia no son numerosos, siendo mucho mayor el número de especies de la familia Bothriuridae, cuyos miembros hasta el momento no revisten importancia médica. Dentro de los tres géneros de Buthidae que viven en el país, el género Tityus es el que posee especies cuya picadura e inoculación de veneno puede provocar accidentes severos. En general, la diferenciación entre Tityus trivittatus, el escorpión de mayor importancia médica de Argentina, respecto a otros escorpiones, es fácil en las provincias de la zona central del país. Sin embargo, las reglas a utilizar para la diferenciación entre escorpiones de importancia médica de aquellos que no la tienen, no son similares en todo el país. En esta actualización, se brindan elementos sencillos y claros para que el personal de salud pueda diferenciar entre las especies de Tityus de importancia médica de los escorpiones de la familia Bothriuridae, ampliamente distribuidos en la superficie del país. De esta forma, se espera que el diag­nóstico acertado sobre la especie de escorpión pueda mejorar la atención en el caso de la picadura por animales potencialmente peligrosos. Por otro lado, permitirá diferenciar a los escorpiones sin importancia médica lo que redundará en la mejor utilización de los recursos disponibles en los niveles de atención primaria, ante la emergencia que representa una picadura de alacrán.

The scorpions of medical importance in the world mostly belong to Buthidae family. In Argentina, members of this family are not numerous, being much most numerous the species from the Bothriuridae family, whose members so far are of no medical importance. Within the three genera of Buthidae that inhabit in the country, only species from Tityus genus can cause severe ac­cidents. The differentiation between the scorpions of highest medical importance in Argentina (Tityus trivittatus), regarding other scorpions, is easy in the provinces of the central region. However, the rules used for the differentiation of medically important scorpions regarding those not dangerous, is not similar through the country. In this update, we provide simple and clear tools for the health personnel to differentiate between species of Tityus with medical importance and the scorpions from Bothriuridae fam­ily, widely distributed in the country. Thus it is expected that the accurate diagnosis of the species of scorpions may improve the attention in the case of the sting of potentially dangerous scorpions. On the other hand, the differentiation of the not dangerous scorpions from those with medical importance will result in the best use of the available resources in primary care level, consider­ing the emergency that represents a scorpion sting.

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The venoms of Bothrops (Rhinocerophis) alternatus (B.a.) from different regions of Argentina have shown biochemical, toxicological and immunological variations. Considering these variations, we produced nine experimental antisera (rabbit, IgG) against venoms from snakes of nine different regions and a pool of venom, comprised of equal amounts of venoms from each region. The immunologic studies (ELISA, Westernblot) showed significant cross reactivity among all regional antivenoms with all regional venoms, with no significant differences regarding the specificity of the immunogens used for the production of antivenom. Neutralization of hemorrhage was variable (although all the antivenoms neutralized this activity in all venoms) and the neutralization of coagulant and phospholipase activities were evident in all cases. Some antivenoms neutralized toxic activities that were absent or very low in the venoms used as immunogen, on other non-homologous venoms (e.g. thrombin like activity). Despite the different toxic potencies of regional venoms, antivenoms developed using venoms of snakes from a particular region showed high immunochemical reactivity and cross-neutralizing capacity on snake venoms from different and distant regions, in occasions over those of the homologous antivenoms. These findings could be used to improve the generation of pools of venoms for the production of antivenoms.

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Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.

Los venenos serpientes pueden presentar variabilidad en sus características bioquímicas y toxicológicas aún en ejemplares de una misma especie. La localización geográfica de los ejemplares es uno de los factores que puede influenciar estas variaciones. Por este motivo se estudió el veneno de ejemplares Bothrops (Rhinocerophis) alternatus ("crucera", "yarará grande"), una de las serpientes de mayor importancia médica de Argentina, de tres regiones diferentes de Córdoba. Se estudió la potencia letal, la actividad hemorrágica, coagulante en plasma y trombina símil y el patrón electroforético de ejemplares de Calamuchita, Traslasierras y del Este de la provincia. El veneno de las serpientes de las tres regiones presentó las actividades características de los venenos de la mayoría de las Bothrops, causando hemorragias y alteraciones en el sistema hemostático, afectando tanto al plasma como actuando directamente sobre el fibrinógeno mediante una actividad trombina símil. Las distintas muestras fueron muy similares en cuanto a sus características bioquímicas ya sus potencias tóxicas, a diferencia de lo observado con veneno de ejemplaresB. alternatusde distintas regiones de otras provincias de la Argentina. El antiveneno Bivalente utilizado por el Ministerio de Salud de Córdoba para tratar los accidentes por Bothrops neutralizó, en todos los casos las actividades tóxicas ensayadas en rangos de potencias neutralizantes muy similares.

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Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.

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RESUMEN

Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.

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A phospholipase enzyme was separated by chromatography from the venom of the snake Bothrops (Rhinocerophis) ammodytoides and characterized. The experimentally determined molecular weight was 13,853.65 Da, and the full primary structure was determined by Edman degradation and mass spectrometry analysis. The enzyme contains 122 amino acids residues closely stabilized by 7 disulfide bridges with an isoelectric point of 6.13. Sequence comparison with other known secretory PLA2 shows that the enzyme isolated belongs to the group II, presenting an aspartic acid residue at position 48 (numbered by convention as Asp49) of the active site, and accordingly displaying enzymatic activity. The enzyme corresponds to 3% of the total mass of the venom. The enzyme is mildly toxic to mice. The intravenous LD50 of this phospholipase in CD-1 mice was around 6 µg/g of mouse body weight (more exactly 117 µg/mouse of 20 g) and the minimal mortal dose (MMD) was estimated to be close to 10 µg/g. In contrast, the LD50 of the venom was circa 2 µg/g mouse body weight. Toxicological analyses of the purified enzyme were performed in vitro and in vivo using experimental animals (mice and rats). The enzyme at high doses caused pulmonary congestion, intraperitoneal bleeding, inhibition of clot retraction and muscle tissue alterations with increasing of creatine kinase levels.

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Se describe el caso de un ejemplar de tortuga mordedora (Chelydra serpentina) que fue hallada con los miembros tetanizados en extensión, midriasis y poca respuesta a estímulos externos, en cuyo recinto se encontró un ejemplar de escorpión Tityus trivittatus. Ante el claro cuadro de envenenamiento, se trató al quelonio con antiveneno escorpiónico específico retornando a un estado de relajación muscular a las seis horas y encontrándoselo totalmente normal a las 24 horas sin mostrar secuelas posteriores. Este es el primer comunicado sobre el envenenamiento de quelonios por escorpiones. Se discuten algunos aspectos de este envenenamiento escorpiónico y su tratamiento con antiveneno específico.

We report the case of a snapping turtle (Chelydra serpentina) found tetanized, with the limbs in extension, mydriasis and poor response to external stimuli, in whose terrarium was found a Tityus trivittatus scorpion. Based on the clear clinical picture of envenoming, the turtle was treated with a specific scorpion antivenin, returning to a state of muscle relaxation after six hours of treatment and it was found totally normal at 24 hours, without envenoming sequelae. This is the first report on turtle envenomation by scorpion. The scorpion envenomation in reptiles and the treatment with specific antivenom is discussed.

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Esta Guía tiene como objetivo básico brindar información sobre: - La forma en que se producen estos envenenamientos, - Las características morfológicas más significativas de las especies de interés sanitario en nuestro país, - Los mapas con la distribución geográfica de las principales especies de escorpiones de interés sanitario de Argentina, - Las manifestaciones clínicas que se deben identificar para realizar el diagnóstico y caracterizar el cuadro clínico según la gravedad, - Las medidas que se deben adoptar para tratar a la persona afectada, - Las intervenciones que deben evitarse para impedir las complicaciones, - Las recomendaciones que se pueden hacer a la población para evitar que ocurran estos incidentes. - La modalidad de Vigilancia Epidemiológica. Protocolos para la Notificación de los Envenenamientos por Escorpión. Ficha Epidemiológica - El Directorio de Centros Especializados en Venenos Animales y Centros de Información, Asesoramiento y Asistencia Toxicológica de la Red Argentina de Toxicología.

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