Freshwater stingrays: study of epidemiologic, clinic and therapeutic aspects based on 84 envenomings in humans and some enzymatic activities of the venom

Freshwater stingrays are very common in the Parana, Paraguay, Araguaia, and Tocantins Rivers and tributaries in Brazil. This study presents the clinical aspects of 84 patients injured by freshwater stingrays. Intense pain was the most conspicuous symptom. Skin necrosis was observed in a high percentage of the victims, mostly fishermen and bathers. The initial therapeutic procedures, like immersion of the affected member in hot water were effective in the initial phases of the envenoming, especially in the control of the acute pain; however, they did not prevent skin necrosis. By SDS-PAGE, the freshwater stingray (Potamotrygon falkneri) venom extract presented a major band of approximately 12 kDa. Several other components distributed between 15 and 130 kDa were detected in the venom extract. Many components with molecular mass above 80 and 100 kDa have gelatinolytic and caseinolytic activities, respectively. Hyaluronidase activity was detected only in a component around 84 kDa in P. falkneri venom extract. Our results demonstrated that the presence of these enzymes could explain partially the local clinical pictures presented by patients wounded by freshwater stingray. (C) 2004 Elsevier Ltd. All rights reserved.

Arraias em rios da região Sudeste do Brasil: locais de ocorrência e impactos sobre a população

INTRODUÇÃO: No presente trabalho objetivamos descrever o processo de colonização da Bacia do Alto Paraná, Sudeste do Brasil, por arraias, demonstrando sua atual situação e provável tendência, os impactos gerados e discutindo algumas ações de manejo e medidas mitigadoras. MÉTODOS: Foram realizadas entrevistas com ribeirinhos e profissionais de saúde para o levantamento de informações sobre a ocorrência de arraias e acidentes associados a estes animais, além de coletas e observações subaquáticas de potamotrigonídeos, entre 2004 e 2009, em localidades situadas nos Estados de São Paulo, Paraná e Mato Grosso do Sul, no Sudeste, Sul e parte do Centro-Oeste do Brasil. RESULTADOS: Três espécies de arraias foram identificadas na área de estudo, demonstrando utilizar os caminhos abertos pela Hidrovia Tietê-Paraná para se dispersarem. Dezesseis vítimas de acidentes envolvendo esses animais foram encontradas, notadamente banhistas e pescadores, chamando a atenção pelo fato dos casos não serem notificados e apresentarem elevada morbidade, com marcante incapacidade temporária para o trabalho. CONCLUSÕES: Este é o primeiro relato de invasão biológica envolvendo espécies de elasmobrânquios conhecido na literatura e, pelas arraias estarem colonizando áreas densamente povoadas e ampliando sua área de distribuição a cada ano, é de se esperar que sua interação negativa com humanos se intensifique, provocando alterações importantes no perfil epidemiológico dos acidentes por animais peçonhentos ocorridos no sudeste brasileiro.

The 5S rDNA family evolves through concerted and birth-and-death evolution in fish genomes: an example from freshwater stingrays

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stirring, charging, and picking: hunting tactics of potamotrygonid rays in the upper Paraná River

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Registro de ocorrência de duas espécies de potamotrigonídeos na região do Alto Rio Paraná e algumas considerações sobre sua biologia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ingestion of catfish by freshwater stingray: possible mistake or inexperience

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biological and biochemical properties of the Brazilian Potamotrygon stingrays : Potamotrygon cf. scobina and Potamotrygon gr. orbignyi

Stingrays of the family Potamotrygonidae are widespread throughout river systems of South America that drain into the Atlantic Ocean. Some species are endemic to the most extreme freshwater environment of the Brazil and cause frequent accidents to humans. The envenomation causes immediate, local, and intense pain, soft tissue edema, and a variable extent of bleeding. The present study was carried out in order to describe the principal biological and some biochemical properties of the Brazilian Potamotrygon fish venoms (Potamotrygon cf. scobina and P. gr. orbignyi). Both stingray venoms induced significant edematogenic and nociceptive responses in mice. Edematogenic and nociceptive responses were reduced when the venom was incubated at 37 or 56 degrees C. The results showed striking augments of leukocytes rolling and adherent cells to the endothelium of cremaster mice induced by both venoms. The data also presented that injection of both venoms induced necrosis, low level of proteolytic activity, without inducing haemorrhage. But when the venoms of both stingray species were injected together with their mucus secretion, the necrotizing activity was more vigorous. The present study provided in vivo evidence of toxic effects for P. cf. scobina and P. gr. orbignyi venoms. (c) 2006 Elsevier Ltd. All fights reserved.