Perinatal Screening of Crotalus durissus terrificus Venom and Antivenom in Rats

Crotalid envenomation carries the highest snakebite mortality rate in Brazil, yet its impact on the fetus during pregnancy remains unclear. In this study, we examined the effects of a moderate, nonlethal dose of Crotalus durissus terrificus venom (vCdt) on pregnant rats on gestational days 5 (V5, embryogenesis phase) and 10 (V10, organogenesis phase). We also evaluated whether antivenom could neutralize these effects. Exposure at V5 tended to increase the average weight of male and female fetuses, as well as the weight of their kidneys and livers. Some fetuses exhibited incomplete cranial ossification and supernumerary rib fragments. All of these effects were fully reversed by antivenom. Exposure at V10 reduced overall fetal weight and tended to increase placental weight while reducing the weights of the kidneys, liver, and heart in male and female fetuses. Antivenom only partially reversed these effects. Thus, vCdt is embryotoxic during embryogenesis and organogenesis, though antivenom therapy is more effective in the early stages of gestation.