Scorpionism in the Amazon: Evidence, Challenges and Actions for Controlling a Neglected Disease.

Scorpion sting envenomations impose an increasing burden in the Amazon and result in a considerable impact on public health. The genus Tityus accounts for nearly all clinically relevant cases, with T. metuendus, T. silvestris and T. obscurus being responsible for most of envenomations in the region. In the state of Amazonas, Manaus and Apuí account for most of cases reported, with an evident expansion to other regions, including the Solimões River region and the Upper Negro River region, where most of the exposed population is found in Indigenous and riverine communities. The increasing burden and high severity rates of scorpion stings in the Amazon may result from the capacity of adaptation of the endemic species to the environmental changes and limitations in providing adequate healthcare to patients. The clinical profile of patients stung by different species has similar local and systemic manifestations. In Manaus, T. metuendus is the species that is most commonly responsible for severe cases observed in children, due to them presenting circulatory collapse and acute respiratory distress, while T. apiacas and T. silvestris present systemic neurological manifestations, characterized by generalized muscle spasms described as the sensation of receiving an electric shock, apparently not reversed by the available antivenom. Scorpionism in the Amazon combines the biological complexity and variability of Tityus species and their venoms, social and environmental determinants and healthcare challenges. These features require solutions of interinstitutional, interdisciplinary networks that are capable of integrating biology, venomics, clinical medicine, public health, environmental sciences and the social sciences.