Development of an acute cutaneous swine model for Loxosceles envenomation

To develop an acute cutaneous swine model for Loxosceles envenomation which could be used to objectively compare various treatment modalities.

Nine weanling, mixed-breed domestic piglets.

Piglets were injected intradermal in the hindlimb with Loxosceles deserta venom in increasing doses and concentrations until consistently large lesions were obtained. A minimum of 3 injections/venom preparation were carried out, with no more than 2 injections/animal. Repeat injections in the same animal were separated by 8 d.

All lesions were measured daily for erythema and necrosis for 7 consecutive days. Data are reported as individual and mean maximal values. The piglets receiving 0.1, 0.2 or 0.3 ml of 5 microliters venom/ml saline developed small inconsistent lesions, with the largest necrotic lesion 5 mm. Those injected with 0.3 ml of venom diluted 15 microliters/ml saline developed small necrotic lesions (mean 4 mm, maximal 10 mm). All piglets injected with 25 microliters of venom diluted to 0.3 ml developed large necrotic lesions (mean 33 mm) with substantial erythema (mean 177 mm).

Intradermal injection of 0.1 ml of 25 microliters purified Loxosceles deserta venom diluted to 0.3 ml with sterile saline produced large necrotic lesions in piglets. This model may be used to study Loxosceles envenomation and treatment.