Envenomations caused by fish in Brazil: an evolutionary, morphological, and clinical vision of a neglected problem

Venomous fish are commonly found in Brazilian waters. The most important marine venomous fish species are stingrays (Dasyatidae, Gimnuridae, Myliobatidae, and Rhinopteridae families), catfish (Ariidae family), scorpionfish and lionfish (both Scorpaenidae family), and toadfish (Batrachoididae family). Meanwhile, Potamotrygonidae stingrays and Pimelodidae catfish are the most important venomous freshwater fish. The mechanisms of envenomation vary and involve various venomous apparatuses and glands. Despite not being highly developed, these venomous apparatuses in fish appear rudimentary, using structures such as fins and rays to inoculate toxins and rarely presenting with specialized structures. Toxins are produced by glandular tissue made up of proteinaceous cells, lacking true glands, and are positioned along the inoculation structures. However, systemic manifestations are rare. No antivenom serum has been developed for any species of American venomous fish. Brazilian venomous fish and their venoms have only recently attracted attention, leading to new studies not only addressing clinical issues in humans, but also exploring the discovery of new active substances with immense pharmacological potential.

Impact of environmental changes on Dermatology.

Urbanization, pollution and the modification of natural landscapes are characteristics of modern society, where the change in human relations with the environment and the impact on biodiversity are environmental determinants that affect the health-disease relationship. The skin is an organ that has a strong interface with the environment and, therefore, the prevalence patterns of dermatoses may reflect these environmental changes. In this article, aspects related to deforestation, fires, urbanization, large-scale agriculture, extensive livestock farming, pollution and climatic changes are discussed regarding their influence on the epidemiology of skin diseases. It is important that dermatologists be aware of their social responsibility in order to promote sustainable practices in their community, in addition to identifying the impacts of environmental imbalances on different dermatoses, which is essential for the prevention and treatment of these diseases.

KAMBÔ: an Amazonian enigma.

The secretions of the Giant Monkey Frog Phyllomedusa bicolor are used by populations in the Amazon regions (mainly the indigenous Katukinas and Kaxinawás). The so-called "toad vaccine" or "kambô" is applied as a medication for infections and to prevent diseases, and also as physical and mental invigorator, and analgesic. Since the 1980s, researchers and companies have been interested in the composition of these secretions. Phyllomedusin, phyllokinin, caerulein and sauvagine are the polypeptides in these secretions that can cause intense effects on smooth muscles, vessels provoking, nausea and vomiting, arterial hypotension, flushing, palpitations, nausea, vomiting, bile secretion and angioedema. These actions are similar to bradykinin. However, the feeling of well-being and improvement of motor skills described by the users seems to be associated with dermorphine, caerulein or deltorphin - peptides with analgesic properties - and their affinity for the opiate receptor systems. Caerulein is a peptide that increases digestive secretions. Phyllomedusin and Phyllokinin lead to blood pressure and digestive effects. Sauvagine release corticotropin and mimics the physiological reactions of exposure to stress. Deltorphins and dermorphins have high affinity for the opiate receptor system and can lead to analgesia. The fame acquired by the therapy motivated the use by individuals from urban areas worldwide, without safety considerations. While in indigenous communities, there is an entire cultural tradition that provides relative safety to the application, however, the extension of use to individuals from urban areas worldwide is a problem, with reports of severe adverse effects and deaths. Undoubtedly, the skin secretions of the Phyllomedusa genus contain substances of intense pharmacological action and that can lead to research for therapeutic uses, but control over their application in rituals outside the forest is needed due the risks presented.

Dermatites de contato causadas por aroeiras (Anacardiaceae) no estado de São Paulo, Brasil / Contact dermatitis caused by mastic (Anacardiaceae) in the state of São Paulo, Brazil

Contexto e objetivos: Aroeira é o nome popular de árvores da família Anacardiaceae, que inclui plantas sensibilizantes como a poison ivy norte-americana (Toxicodendron radicans), o cajueiro (Anacardium occidentale) e a mangueira (Mangifera indica). Este estudo procura caracterizar o conhecimento sobre as aroeiras e a frequência de manifestações clínicas em camponeses. Desenho e local: Foi realizado estudo retrospectivo e prospectivo com pacientes e acompanhantes residentes em ampla área rural de cerrado no Centro-Oeste paulista. Métodos: A frequência e a relação causal entre a exposição a aroeiras, comuns na região, e a dermatite eczematosa típica foi pesquisada. Para a avaliação, foi utilizado um questionário específico. Resultados: Todos os 39 entrevistados conheciam aroeiras (100%) e 17 deles (43,58%) relataram ter se aproximado ou descansado sob essas árvores. Mais da metade deles (56,41% ou 22 indivíduos) relataram dermatites que relacionaram às arvores. Os demais entrevistados não desenvolveram reações, mas conheciam pessoas que o fizeram (43,59%). Três pacientes, ou 7,69% da amostra, apresentavam lesões de padrão eczematoso, creditando-as ao contato com aroeiras-bravas (Lithraea molleoides). Discussão: Devido à alta frequência com que essas árvores são encontradas no campo (cerrado brasileiro) e aos dados obtidos, percebemos também uma alta frequência de sensibilização nas áreas rurais. Conclusões: É imperativo que as campanhas de orientação e alerta sejam desenvolvidas para aumentar a conscientização sobre riscos potenciais, de modo que o contato com essas árvores seja evitado, evitando condições alérgicas que podem ser tão extensas quanto graves.

Identification of two novel cytolysins from the hydrozoan Olindias sambaquiensis (Cnidaria).

BACKGROUND: Although the hydrozoan Olindias sambaquiensis is the most common jellyfish associated with human envenomation in southeastern and southern Brazil, information about the composition of its venom is rare. Thus, the present study aimed to analyze pharmacological aspects of O. sambaquiensis venom as well as clinical manifestations observed in affected patients. Crude protein extracts were prepared from the tentacles of animals; peptides and proteins were sequenced and submitted to circular dichroism spectroscopy. Creatine kinase, cytotoxicity and hemolytic activity were evaluated by specific methods. RESULTS: We identified two novel cytolysins denominated oshem 1 and oshem 2 from the tentacles of this jellyfish. The cytolysins presented the amino acid sequences NEGKAKCGNTAGSKLTFKSADECTKTGQK (oshem 1) and NNSKAKCGDLAGWSKLTFKSADECTKTGQKS (oshem 2) with respective molecular masses of 3.013 kDa and 3.375 kDa. Circular dichroism revealed that oshem 1 has random coils and small α-helix conformation as main secondary structure whereas oshem 2 presents mainly random coils as its main secondary structure probably due to the presence of W (13) in oshem 2. The hemolysis levels induced by oshem 1 and oshem 2 using a peptide concentration of 0.2 mg/mL were, respectively, 51.7 ± 6.5% and 32.9 ± 8.7% (n = 12 and p ≤ 0.05). Oshem 1 and oshem 2 showed significant myonecrotic activity, evaluated by respective CK level measurements of 1890.4 ± 89 and 1212.5 ± 103 (n = 4 and p ≤ 0.05). In addition, myonecrosis was also evaluated by cell survival, which was measured at 72.4 ± 8.6% and 83.5 ± 6.7% (n = 12 and p ≤ 0.05), respectively. The structural analysis showed that both oshem 1 and oshem 2 should be classified as a small basic hemolytic peptide. CONCLUSION: The amino acid sequences of two peptides were highly similar while the primary amino acid sequence analysis revealed W (22th) as the most important mutation. Finally oshem 1 and oshem 2 are the first cytolytic peptides isolated from the Olindias sambaquiensis and should probably represent a novel class of cytolytic peptides.

Injuries by marine and freshwater stingrays: history, clinical aspects of the envenomations and current status of a neglected problem in Brazil.

Stingrays are a group of rays - cartilaginous fish related to sharks - that have whiplike tails with barbed, usually venomous spines and are found around the world, especially the marine species. Despite recent reports of accidents involving these fish, they are not aggressive, reacting only when stepped on or improperly handled. Injuries by stingrays are seldom mentioned by historians, although they have always been present in riverine communities of inland waters and in South American coasts. Indeed, envenomations by stingrays are quite common in freshwater and marine fishing communities. Although having high morbidity, such injuries are neglected because they have low lethality and usually occur in remote areas, which favor the use of folk remedies. In the present review article, historical aspects of injuries caused by stingrays in Brazil and their distribution on the coast of São Paulo state and riverine communities of the North, Midwest and Southeast regions were studied. In addition, other aspects were analyzed such as clinical features, therapeutic methods, preventive measures and trends in occurrence of these accidents in the country, particularly in areas in which freshwater stingrays had not been previously registered, being introduced after breaching of natural barriers.

Injuries by marine and freshwater stingrays: history, clinical aspects of the envenomations and current status of a neglected problem in Brazil

Stingrays are a group of rays – cartilaginous fish related to sharks – that have whiplike tails with barbed, usually venomous spines and are found around the world, especially the marine species. Despite recent reports of accidents involving these fish, they are not aggressive, reacting only when stepped on or improperly handled. Injuries by stingrays are seldom mentioned by historians, although they have always been present in riverine communities of inland waters and in South American coasts. Indeed, envenomations by stingrays are quite common in freshwater and marine fishing communities. Although having high morbidity, such injuries are neglected because they have low lethality and usually occur in remote areas, which favor the use of folk remedies. In the present review article, historical aspects of injuries caused by stingrays in Brazil and their distribution on the coast of São Paulo state and riverine communities of the North, Midwest and Southeast regions were studied. In addition, other aspects were analyzed such as clinical features, therapeutic methods, preventive measures and trends in occurrence of these accidents in the country, particularly in areas in which freshwater stingrays had not been previously registered, being introduced after breaching of natural barriers.

Injuries by marine and freshwater stingrays: history, clinical aspects of the envenomations and current status of a neglected problem in Brazil

Stingrays are a group of rays - cartilaginous fish related to sharks - that have whiplike tails with barbed, usually venomous spines and are found around the world, especially the marine species. Despite recent reports of accidents involving these fish, they are not aggressive, reacting only when stepped on or improperly handled. Injuries by stingrays are seldom mentioned by historians, although they have always been present in riverine communities of inland waters and in South American coasts. Indeed, envenomations by stingrays are quite common in freshwater and marine fishing communities. Although having high morbidity, such injuries are neglected because they have low lethality and usually occur in remote areas, which favor the use of folk remedies. In the present review article, historical aspects of injuries caused by stingrays in Brazil and their distribution on the coast of São Paulo state and riverine communities of the North, Midwest and Southeast regions were studied. In addition, other aspects were analyzed such as clinical features, therapeutic methods, preventive measures and trends in occurrence of these accidents in the country, particularly in areas in which freshwater stingrays had not been previously registered, being introduced after breaching of natural barriers.(AU)

Envenenamento por baiacus (peixes-bola): revisão sobre o tema / Poisoning by pufferfish (ballfish): review on the topic

A ingestão de algumas espécies de baiacus pode causar graves envenenamentos por tetrodo-toxina, uma potente neurotoxina presente na pele, ovários, fígado e intestinos desses peixes. A tetrodotoxina bloqueia canais de sódio na junção neuromuscular, causando impossibilidade de condução do impulso nervoso para os músculos, sendo considerada uma das mais potentes toxinas encontradas na natureza.Vários animais apresentam tetrodotoxina e derivados em órgãos e tecidos para sua defesa. A toxina parece ser apenas armazenada, sendo produzida por bactérias.Intoxicações por tetrodotoxina causam paralisia muscular progressiva que atinge sua máxima intensidade em cerca de 24 horas. O grande risco é a morte por insu?ciência respiratória.Não existe tratamento especí?co para a intoxicação por tetrodotoxina; a lavagem gástrica é importante nas primeiras seis horas do quadro e, em fases posteriores, o recurso de?nitivo é a assistência ventilatória mecânica, mas o índice de óbito é alto mesmo assim.