An in vitro efficacy analysis of bothropic antivenom against venoms of different Bothrops species

Antivenoms are the only specific medications available for the treatment of snakebite envenomation, which represents an important global public health concern. The success of treatment depends, in part, on the ability of the antivenom used to bind to and neutralize the toxins present in the venom. To achieve this efficacy, it is important that the immunizing venom pool be representative of the snake fauna to be covered, which is challenging given the inter- and intraspecific variability among snake venoms. In Brazil, snakes of the genus Bothrops are responsible for most snakebite accidents, and the antivenom used in the country is produced from a pool of five different Bothrops venoms (B. jararaca, B. jararacussu, B. alternatus, B. moojeni, and B. neuwiedi). However, quality control of antivenom efficacy during the production process was carried out exclusively against B. jararaca venom. Thus, the aim of this study was to develop and standardize an avidity ELISA for the analysis of serum samples obtained from horses immunized with the Bothrops venom pool against the different venoms that comprise this pool, also including B. atrox venom, as an auxiliary tool for evaluating antivenom efficacy. The avidity ELISA revealed variations in avidity both among the four batches of equine serum samples analyzed (inter-batch variation) and among the six Bothrops venoms included in the study (intra-batch variation).The avidity ELISA showed good applicability for Bothrops venoms and good intra- and inter-plate repeatability, suggesting the potential of this assay for implementation in preliminary efficacy evaluations of Bothrops antivenom production.