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Table 3 Efficacy of oral moxidectin (24 µg/kg) compared to Heartgard® Plus or Interceptor® Plus (ZoeLA strain)

From: Preventive efficacy of four or six monthly oral doses of 24 µg/kg moxidectin compared to six monthly doses of Heartgard® Plus or Interceptor® Plus against macrocyclic lactone-resistant heartworm (Dirofilaria immitis) strains in dogs

Treatment Oral 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 24, 36, 36, 39, 41, 41 35.6f na
Moxidectin 24 µg/kg 0, 30, 60, 90 5 of 6 0, 1, 1, 1, 2, 3 1.1g 96.8
Moxidectin 24 µg/kg 0, 30, 60, 90, 120, 150 5 of 6 0, 1, 1, 2*, 2, 4 1.4g 96.1
Heartgard® Plus Min. of 6 µg/kgd 0, 30, 60, 90, 120, 150 6 of 6 25, 25, 27, 27, 36, 36 29.0f 18.7
Interceptor® Plus Min. of 500 µg/kge 0, 30, 60, 90, 120, 150 6 of 6 16, 26, 28, 33, 34, 37 28.1f 21.2
  1. aEach dog was inoculated with 50 infective ZoeLA L3 of D. immitis on Day -30, except for one dog (*) treated with six monthly doses of moxidectin which received 49 infective larvae
  2. bGeometric mean counts with the same superscript letters (f-g) are not significantly different (P ≥ 0.05)
  3. cAll dogs were necropsied for recovery of adult D. immitis on Day 243 (273 days post-inoculation)
  4. dHeartgard® Plus (ivermectin + pyrantel pamoate) administered according to commercial label directions which resulted in administration of 6.2–15.5 µg/kg of ivermectin
  5. eInterceptor® Plus (milbemycin oxime + praziquantel) administered according to commercial label directions which resulted in administration of 0.5–1.2 mg/kg milbemycin oxime