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Table 3 Efficacy of oral Simparica Trio® compared to Heartgard® Plus or Interceptor® Plus (ZoeLA strain)

From: Preventive efficacy of six monthly oral doses of Simparica Trio®, Heartgard® Plus, and Interceptor® Plus against a macrocyclic lactone-resistant strain (ZoeLA) of heartworm (Dirofilaria immitis) in dogs

Treatment Oral ML dosage Days of treatment No. of infected dogsa Adult D. immitis worm counts Efficacy compared to negative controlc
Individual worm counts Geometric meanb % Reduction
Negative control na 0, 30, 60, 90, 120, 150 6 of 6 23, 34, 36, 37, 40, 48 35.5 d na
Simparica Triof Min. 24 µg/kg moxidectin 0, 30, 60, 90, 120, 150 5 of 6 0, 1, 1, 1, 1‡, 3‡ 1.0e 97.2
Heartgard plusg Min. of 6 µg/kg ivermectin 0, 30, 60, 90, 120, 150 6 of 6 22, 33, 33, 34, 38, 3‡‡, 8 32.5d 8.5
Interceptor plus Min. of 500 µg/kg milbemycin oxime 0, 30, 60, 90, 120, 150 6 of 6 10, 12, 32, 32, 32, 34 22.8d 35.9
  1. aEach dog was inoculated with 50 infective ZoeLA L3 of D. immitis on day −30
  2. bGeometric mean counts with the same superscript letters (d–e) are not significantly different (P > 0.05)
  3. cAll dogs were necropsied for recovery of adult D. immitis on day 241 (271 days post-inoculation)
  4. fAnalysis excluding underdosed dogs removed two dogs from this group with individual worm counts designated (‡); three of the four dogs remaining were infected with a geometric mean of 0.8 worms and reduction of 98.1%
  5. gAnalysis excluding underdosed dogs removed one dog from this group with an individual worm count designated (‡‡); five of the five dogs remaining were infected with a geometric mean of 31.5 worms and reduction of 11.3%