A comprehensive overview of fish envenomation and venom toxicity in Brazil

Abstract

Background: Brazilian waters are home to various venomous fish species, each with its unique venom composition. Although common, envenomation cases are largely underreported, leading to a lack of public health policies for prevention and treatment. Some of the most clinically relevant fish in Brazil include the stingray <i>Potamotrygon orbignyi</i>, the toadfish <i>Thalassophryne nattereri</i>, the scorpionfish <i>Scorpaena plumieri</i>, and the catfish <i>Pseudoplatystoma fasciatum</i> and <i>Cathorops spixii</i>. Methods: We comprehensively searched reports about accidents involving venomous fish in Brazil and compared the toxic activities of some medically relevant species. Results: From the biochemical and toxicological evaluation, we found that venoms show a hierarchy in the ability to induce local toxic effects in mice, probably related to the venom compound diversity with species-specific toxins. <i>T. nattereri</i> venom presents greater toxicity, causing more severe local responses than that of <i>P. orbignyi</i>, <i>C. spixii</i>, and <i>P. fasciatum</i>, which cause moderate reactions. The <i>S. plumieri</i> venom induced only a moderate level of edema and could not cause nociception or necrosis. These results highlight that envenomation by <i>P. orbigny</i>, <i>C. spixii</i>, and <i>S. plumieri</i> is marked by proteins with intense hemolytic/proteolytic and phospholipase activity. On the other hand, <i>T. nattereri</i> and <i>P. fasciatum</i> offered a broader panel of new toxin families. Conclusion: Knowledge of fish venom biochemical and toxicological activities is crucial to antivenom therapy development and helps endorse the study of venomous fish and their impact on the public health system.