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

Table 1 Efficacy of oral moxidectin against ML-resistant heartworms compared to Heartgard® Plus or Interceptor® Plus: study designs

Group	Treatment	Oral dosage	No. of dogs	Day of L₃D. immitis inoculation^a	Days of treatment	Days of blood microfilariae and adult D. immitis antigen testing^b	Day of necropsy and adult D. immitis worm recovery
T01	Negative control	na	6	-30	0, 30, 60, 90, 120, 150	-36 or -30, 60, 180, 210, 236 or 243	237 or 243
T02	Moxidectin	24 µg/kg	6	-30	0, 30, 60, 90
T03	Moxidectin	24 µg/kg	6	-30	0, 30, 60, 90, 120, 150
T04	Heartgard® Plus	Min. of 6 µg/kg^c	6	-30	0, 30, 60, 90, 120, 150
T05	Interceptor® Plus	Min. of 500 µg/kg^c	6	-30	0, 30, 60, 90, 120, 150

^aEach dog was inoculated with 50 infective L₃ of D. immitis of either ZoeLA (Study 1) or JYD-34 (Study 2)
^bDay 180 testing only conducted in Study 2
^cHeartgard® Plus and Interceptor® Plus administered at their approved dosages according to their commercial label directions

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