Experimental cantharidiasis in the horse.

The research investigates the effects of cantharidin, a toxic compound in blister beetles, in horses through experimental dosing. The study sought to understand the toxicity effects while observing the physiological changes and clinical signs exhibited by horses after exposure to different cantharidin dosages.

Methodology

• The experiment involved 10 horses partitioned into two groups. The first group included 8 horses (group 1) while the second group had 2 horses (group 2).
• Group 1 horses received a cantharidin dosage of 450 to 489 micrograms/kg of body weight, while the group 2 horses were given higher doses at 720 micrograms/kg. The doses were administered via a nasogastric tube in crystalline form, mixed in alfalfa cake or aqueous suspension.
• Observations were taken and recorded at 6-hour intervals for 36 hours and once again at 48 hours after cantharidin administration.

Findings

• From the experiment’s result, three horses died: two from group 2 and one from group 1.
• In all the horses, significant increments in cardiac rate, respiratory rate, and rectal temperature were observed. There was also a noted decrease in total serum calcium, serum magnesium, and potassium concentrations during at least one 6-hour period post-administration.
• At the 48-hour mark, calcium and magnesium levels were still noticeably low, while other physiological values had normalized. Arterial oxygen tension, total protein, serum creatine kinase, arterial CO2, and plasma bicarbonate were found reduced in surviving horses during one or more periods.
• Clinical signs of the cantharidin dosage included anorexia, depression, severe gingival and oral mucosal erosions, washing of the muzzle in water, a stiff, short-strided gait, and synchronous diaphragmatic flutter.

Conclusion

• The horses’ physiological and biochemical changes, consistent across the group despite dosage differences, suggest a direct relationship between cantharidin and these effects. This gives insight into cantharidin’s toxicity in larger animals like horses and may guide preventive measures against blister beetle intake.