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Table 6 Efficacy of oral moxidectin (24 µg/kg) against ML-resistant heartworm strains compared to Heartgard® Plus or Interceptor® Plus: summary

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

Oral treatmenta No. of monthly treatmentsb ZoeLA JYD-34
No. of infected dogsc Adult D. immitis worm counts Efficacy compared to negative control (%) No. of infected dogsc Adult D. immitis worm counts Efficacy compared to negative control (%)
Range Geometric mean Range Geometric mean
Moxidectin 1 Not tested 8 of 8 7–29 16.8 53.2d
Moxidectin 3 1 of 5 0–1 0.1 99.5d 1 of 5 0–2 0.2 98.8d
Moxidectin 4 5 of 6 0–3 1.1 96.8e 5 of 6 0–4 1.3 95.9e
Moxidectin 6 5 of 6 0–4 1.4 96.1e 2 of 6 0–1 0.2 99.3e
Heartgard® Plus 6 6 of 6 25–36 29.0 18.7e 6 of 6 6–18 11.9 63.9e
Interceptor® Plus 6 6 of 6 16–37 28.1 21.2e 6 of 6 10–22 14.9 54.6e
  1. aMoxidectin administered at exact 24 µg/kg dosage. Heartgard® Plus and Interceptor® Plus administered according to commercial label directions which resulted in administration of 6.2–15.5 µg/kg of ivermectin and 0.5–1.2 mg/kg milbemycin oxime
  2. bTreatment administration days: 1 monthly treatment: Day 0; 3 monthly treatments: Days 0, 28 and 56 (studies from data reference 1) or Days 0, 30, and 60 (studies from this paper); 4 monthly treatments: Days 0, 30, 60 and 90; 6 monthly treatments: Days 0, 30, 60, 90, 120 and 150
  3. cEach dog inoculated with 50 D. immitis L3 on Day -30 with adult heartworm recovery at necropsy 133 to 273 days after L3 inoculation
  4. dData reference: McTier et al. [4]
  5. eData reference: this paper