Simparica Trio® kills Ctenocephalides felis on dogs and provides month-long protection against the transmission of Dipylidium caninum.

BACKGROUND

The cestode Dipylidium caninum is known to infect dogs via the ingestion of an intermediate flea host, typically Ctenocephalides felis. Simparica Trio® is an oral combination drug product for dogs effective in the treatment and prevention of fleas, including C. felis. Here, we report two laboratory studies evaluating the efficacy of a single administration of Simparica Trio at the minimum label dosage of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin, and 5 mg/kg pyrantel (as pamoate salt) in preventing D. caninum infection in dogs for 1 month through killing of C. felis.

METHODS

A total of 20 dogs (n = 10 per group) proven to be suitable hosts for C. felis were used in each of the two studies. Treatment occurred on day 0, with each dog given either the placebo or Simparica Trio. On days 0 (after treatment), 7, 14, 21, and 30, dogs were infested using 200 (± 5) unfed D. caninum-infected C. felis. Live flea counts were conducted on day 33 (72 ± 2 h after day 30 infestation). All dogs were euthanized on day 58, and each dog was necropsied for the recovery of D. caninum scolexes from the gastrointestinal tract.

RESULTS

Placebo-treated dogs had adequate flea infestations and cestode infections in both studies. Simparica-Trio-treated dogs were free of fleas on day 33 (100% efficacy) and had significantly lower mean flea counts compared with placebo-treated dogs (P ≤ 0.0007). Scolex counts in Simparica-Trio-treated dogs were also significantly decreased compared with placebo-treated dogs in both studies. The efficacy of Simparica Trio against D. caninum based on least squares mean scolex counts was 100% (P < 0.0001) in study 1 and 92.1% (P = 0.0033) in study 2.

CONCLUSIONS

The efficacy provided by Simparica Trio against C. felis at the minimum dosage of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin, and 5 mg/kg pyrantel (as pamoate salt) prevented D. caninum infection in dogs for 1 month.