Venomous Bites, Stings and Poisoning by European Vertebrates as an Overlooked and Emerging Medical Problem: Recognition, Clinical Aspects and Therapeutic Management.

Europe presents a high number of venomous and poisonous animals able to elicit medically relevant symptoms in humans. However, since most of the accidents involving venomous or poisonous animals in Europe are unreported, their incidence and morbidity are severely overlooked. Here we provide an overview of the European vertebrate species of greatest toxicological interest, the clinical manifestations their toxins can cause, and their treatment. We report the clinical symptoms induced by envenomations and poisoning caused by reptiles, fishes, amphibians and mammals in Europe, ranging from mild, local symptoms (e.g., erythema, edema) to systemic and potentially deadly. The present work constitutes a tool for physicians to recognize envenomation/poisoning symptoms caused by the most medically relevant European vertebrates and to decide which approach is the most appropriate to treat them.

Action of heparin and acetylcholine modulators on the neurotoxicity of the toad Rhinella schneideri (Anura: Bufonidae) in Brazil / Acción de la heparina y moduladores de acetilcolina en la neurotoxicidad del sapo Rhinella schneideri (Anura: Bufonidae) en Brasil

Abstract Introduction: Rhinella schneideri is a toad widely distributed in South America and its poison is characterized by inducing cardiotoxicity and neurotoxicity. Objective: In this work, we investigated pharmacological strategies to attenuate the peripheral neurotoxicity induced by R. schneideri poison in avian neuromuscular preparation. Methods: The experiments were carried out using isolated chick biventer cervicis preparation subjected to field stimulation for muscle twitches recordings or exposed to acetylcholine and potassium chloride for contracture responses. Results: Poison (10 μg/ml) produced complete neuromuscular blockade in chick biventer cervicis preparation within approximately 70 min incubation (times for 50 and 90 % blockade: 15 ± 3 min and 40 ± 2 min, respectively; P < 0.05, N= 5); contracture responses to exogenous acetylcholine and KCl were unaffected by poison indicating no specificity with postsynaptic receptors or myotoxicity, respectively. Poison (10 μg/ml)-induced neuromuscular blockade was not prevented by heparin (5 and 150 IU/ml) under pre- or post-treatment conditions. Incubation at low temperature (23-25 °C) abolished the neuromuscular blockade; after raising the temperature to 37 °C, the complete neuromuscular blockade was slightly slower than that seen in preparations directly incubated at 37 °C (times for 50 and 90 % blockade: 23 ± 2 min and 60 ± 2.5 min, respectively; P < 0.05, N= 4). Neostigmine (3.3 μM) did not reverse the neuromuscular blockade in BC preparation whereas 3,4-diaminopyridine (91.6 μM) produced a partial and sustained reversal of the twitch responses (29 ± 7.8 % of maximal reversal reached in approximately 40 min incubation; P < 0.05, N= 4). Conclusions: R. schneideri poison induces potent peripheral neurotoxicity in vitro which can be partially reversible by 3,4-diaminopyridine.

Resumen Introducción: Rhinella schneideri está ampliamente distribuida en Suramérica y su veneno es caracterizado por inducir cardiotoxicidad y neurotoxicidad. Objetivo: En este trabajo, investigamos estrategias farmacológicas para atenuar la neurotoxicidad periférica inducida por el veneno de R. schneideri en preparaciones neuromusculares de aves. Métodos: Los experimentos fueron realizados usando preparaciones de biventer cervicis de pollos sometidas a estimulación de campo para el registro de las contracciones musculares o expuestas a la acetilcolina y al cloruro de potasio para la respuesta contractural. Resultados: El veneno (10 µg/ml) provocó un bloqueo neuromuscular completo en las preparaciones después de aproximadamente 70 min de incubación (tiempos para 50 y 90 % de bloqueo: 15 ± 3 min y 40 ± 2 min, respectivamente; P < 0.05, N = 5); las contracturas en respuesta a la acetilcolina y el KCl exógenos no fueron afectadas por el veneno, indicando que no hay una interacción especifica con receptores postsinápticos o miotoxicidad respectivamente. El bloqueo neuromuscular causado por el veneno (10 µg/ml) no fue prevenido por la heparina (5 y 150 UI/ml) bajo condiciones pre y post-tratamiento. La incubación a bajas temperaturas (23-25 ºC) abolió el bloqueo neuromuscular; después de aumentar la temperatura a 37 ºC, el bloqueo neuromuscular total fue levemente más lento que el visto en preparaciones directamente incubadas a 37 ºC (tiempos para 50 y 90 % de bloqueo: 23 ± 2 min y 60 ± 2.5 min, respectivamente; P < 0.05, N= 4). Neostigmina (3.3 µM) no revirtió el bloqueo neuromuscular, mientras que 3.4-diaminopiridina (91.6 µM) produjo una reversión parcial y sostenida de las respuestas neuromusculares (29 ± 7.8 % de la reversión máxima alcanzada en aproximadamente 40 min de incubación; P < 0.05, N = 4). Conclusiones: El veneno de R. schneideri indujo neurotoxicidad periférica potente in vitro, el cual puede ser revertido por 3.4-diaminopiridina.