An Epidemiological Overview of Envenomation Involving Latrodectus sp. and Unidentified Spider Species in Southern Brazil

Background: Spiders of the order Araneae are ecologically significant predators, although only a few species pose a medical threat to humans. Among them, the Latrodectus genus stands out due to its potent venom, which can cause severe systemic symptoms Objective: The aim of this study was to describe the epidemiology of latrodectism and accidents with other spiders in the southern region of Brazil from 2011 to 2022. Methods: Data were collected from DataSUS/Tabnet and analyzed using descriptive statistics, chi-square tests, and principal component analysis (PCA) to describe the epidemiological profile of these accidents. Results: Findings show that Santa Catarina reported the highest number of latrodectism cases (112), followed by Rio Grande do Sul (63) and Paraná (44). Accidents involving unidentified spiders exceeded 247,000 in the region, with Santa Catarina also recording the highest frequency. Seasonal patterns indicated an increase in incidents during warmer months and a decline in winter. Latrodectism was more common among older adults (65–80 years), while accidents with unidentified spiders were more evenly distributed across age groups. This study underscores the importance of accurate species identification in the clinical management of spider bites and in developing effective public health strategies. Moreover, it highlights the need for further research on the Latrodectus genus in Brazil, given its medical relevance and the current gaps in scientific knowledge.