Content area
Full Text
Background
There is limited information in the literature regarding ivermectin toxicity in reptiles, especially snakes. Additionally this case represents an important lesson for veterinary clinicians. When treating a collection of prey/food items, it is prudent to wait a few days prior to feeding out to reptiles to make sure the food item is healthy and will not secondarily poison the reptile.
Case presentation
Cases 1 and 2
A colony of feeder rats and mice kept as a food source for a large reptile collection were diagnosed with mite infestation. Rodents were fed an ivermectin-impregnated food, manufactured by a commercial company. The colony was treated only once, when five pellets (weighing 3 g each) were administered to each cage of three rats or four mice. Two hours later animals were clinically normal and three mice were collected and fed to three South American green snakes (Philodryas baroni ). The next day, 80 per cent of all rodents were affected with tremors, hypersensitivity to stimuli, seizures or death. Within 72 hours two of the three snakes were found dead and one was moribund. Over the 72-hour period 98 per cent of the rodents succumbed and the rest were humanely euthanized. It was later discovered that a miscalculation in manufacture resulted in a 100-fold excess in the ivermectin concentration in the rodent feed.
Case 3
The third snake was a seven-year-old male South American green snake (P baroni ) weighing 300 g. It was found depressed, weak and slow to right itself within 72 hours after eating one mouse.
Investigations
The first two snakes (snake 1 and 2) were 10-year-old male South American green snakes (P baroni ) weighing 344 and 334 g respectively. Pathology of the two deceased snakes revealed only benign or age-related changes not associated with intoxication. Brain tissue from both deceased snakes and one affected feeder mouse were submitted for ivermectin testing and revealed ivermectin was present in all three brains. Snake 1 had 1600 ppb and snake 2 had 500 ppb, while the feeder mouse had 270 ppb.
Treatment
There is no specific antidote for treating patients with macrolide toxicity. In cases of overdose, emesis is recommended if ingestion occurred within two hours, as...