Experimental Bothrops atrox envenomation: Efficacy of antivenom therapy and the combination of Bothrops antivenom with dexamethasone

Abstract

Bothrops atrox snakes are the leading cause of snake bites in Northern Brazil. The venom of this snake is not included in the antigen pool used to obtain the Bothrops antivenom. There are discrepancies in reports on the effectiveness of this antivenom to treat victims bitten by B. atrox snakes. However, these studies were performed using a pre-incubation of the venom with the antivenom and, thus, did not simulate a true case of envenomation treatment. In addition, the local lesions induced by Bothrops venoms are not well resolved by antivenom therapy. Here, we investigated the efficacy of the Bothrops antivenom in treating the signs and symptoms caused by B. atrox venom in mice and evaluated whether the combination of dexamethasone and antivenom therapy enhanced the healing of local lesions induced by this envenomation. In animals that were administered the antivenom 10 minutes after the envenomation, we observed an important reduction of edema, dermonecrosis, and myonecrosis. When the antivenom was given 45 minutes after the envenomation, the edema and myonecrosis were reduced, and the fibrinogen levels and platelet counts were restored. The groups treated with the combination of antivenom and dexamethasone had an enhanced decrease in edema and a faster recovery of the damaged skeletal muscle. Our results show that Bothrops antivenom effectively treats the envenomation caused by Bothrops atrox and that the use of dexamethasone as an adjunct to the antivenom therapy could be useful to improve the treatment of local symptoms observed in envenomation caused by Bothrops snakes.

Antivenom therapy: efficacy of premedication for the prevention of adverse reactions

“…Recently, Santos-Barreto et al [ 29 ] experimentally studied the combination of antivenom and dexamethasone and concluded that the use of this glucocorticoid as an adjunct to the antivenom therapy could be useful to improve the treatment of local symptoms observed in Bothrops envenomation.…”

Venom complexity of Bothrops atrox (common lancehead) siblings

“…In fact, B. atrox exhibits a dynamic use of its habitat, being known as one of the most active hunters of the Bothrops genus [9,11,12]. B. atrox venom causes mainly local damage, such as edema, hemorrhage and necrosis, apart from systemic effects, including blood coagulation disorders [13,14]. In lethal cases, hemorrhage leads to cardiovascular shock and acute renal failure secondary to acute tubular necrosis and occasionally glomerulonephritis [7,15].…”

Insights into the Mechanisms Involved in Strong Hemorrhage and Dermonecrosis Induced by Atroxlysin-Ia, a PI-Class Snake Venom Metalloproteinase

“…The identification of a potent dermonecrotic factor in B. atrox venom has a clinical implication explaining why some patients bitten by B. atrox present more severe local lesions. Moreover, dermonecrosis induced by B. atrox venom in mice is not neutralized by antivenom, except if the antivenom is administrated soon after venom injection [ 49 ]. Thus, our results are important since they indicate that dermonecrosis is a direct effect of toxins and Atroxlysin-Ia may contribute greatly to the patient’s local condition thus deserving special attention for its neutralization by antivenoms.…”