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Table 2 Adult D. immitis antigen and microfilariae test results (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 group Days of treatment Individual Day-35 Day 60 Day 180 Day 210 Day 236
Ag MF Ag MF Ag MF Ag MF Ag MF
Placebo 0, 30, 60, 90, 120, 150 1  +   +   +   +   +   + 
2  +   +   +   +   +   + 
3  +   +   +   +   +   + 
4  +   +   +   +   +   + 
5  +   +   +   +   +   + 
6  +   +   +   +   +   + 
Simparica Trio®a 0, 30, 60, 90, 120, 150 1 [−]
2‡  +   +   + 
3
4‡ [−]
5 [−]
6  +   + 
Heartgard® Plusb 0, 30, 60, 90, 120, 150 1  +   +   +   +   +   + 
2  +   +   +   +   +   + 
3  +   +   +   +   +   + 
4  +   +   +   +   +   + 
5  +   +   +   +   +   + 
6  +   +   +   +   + 
Interceptor® Plusc 0, 30, 60, 90, 120, 150 1  +   +   +   +   +   + 
2  +   +   +   +   +   + 
3  +   +   +   +   +   + 
4  +   +   +   +   +   + 
5  +   +   +   +   +   + 
6  +   +   +   + 
  1. aSimparica Trio (24 µg/kg moxidectin + 1.2 mg/kg sarolaner + 5 mg/kg pyrantel) was administered according to commercial label direction, which resulted in the administration of {23.1‡}25.0–44.9 µg/kg of moxidectin
  2. bHeartgard Plus (6 µg/kg ivermectin + 5 mg/kg pyrantel) administered according to commercial label directions, which resulted in administration of {5.62‡} 6.2–11.8 µg/kg of ivermectin
  3. cInterceptor Plus (500 µg/kg milbemycin oxime + 5 mg/kg praziquantel) administered according to commercial label directions, which resulted in administration of 0.5–1.0 mg/kg milbemycin oxime
  4. ‡ Designates individuals that were mis-dosed and altered dosing outside of commercial labeling that resulted
  5. Brackets [] indicate samples heat-treated and adult heartworm antigen tests conducted again that were negative after heat treatment
  6. Ag, adult D. immitis antigen test; MF, D. immitis microfilariae test; Min, minimum; − negative, + positive