Veterinarian/Superintendent Chuan Animal Hospital Taipei, Taipei, Taiwan (Republic of China)
Abstract: Background Canine heartworm (HW) disease requires symptomatic treatment and, ideally, parasite clearance. The American Heartworm Society recommends a three-dose melarsomine protocol (AHS). An extended-release injectable moxidectin protocol (MOX) offers a simpler, less expensive, and potentially equally effective alternative. Comparative studies, however, are limited.
Hypothesis/Objectives The MOX protocol is comparable to the AHS-3 protocol in clearing HW infections.
Animals With owner consent, 24 client-owned HW antigen-positive Taiwanese dogs were randomized into two groups of 12.
Methods Prospective, single-blind, randomized 360-day trial, comparing MOX (moxidectin 0.5mg/kg (Proheart 12®, Zoetis), doxycycline, and prednisone) to AHS (three-dose melarsomine 2.5mg/kg (Imiticide®,Boehringer Ingelheim), doxycycline, and prednisone). Moxidectin was repeated at 6-months to HW antigen-positive MOX dogs. Treatment was considered effective when a dog tested HW antigen-negative. Data are presented as mean (SD); The statistical comparison of the time to antigen negativity between groups was conducted using the log-rank test.
Results Eleven dogs (91.67%) in each group achieved antigen-negativity within 360 days. The mean time to HW-negativity was 127 days (median 104; range 89-242 days) and 154 days (median 130; range 86-313; P>0.05) in the AHS and MOX groups, respectively. Three MOX dogs, HW-positive at 180-days, required a second moxidectin injection and 1 remained antigen-positive at Day 360. One AHS dog died suddenly on Day 108. Other than this post-arsenical death, no significant adverse events were noted in either group.
Conclusions and Clinical Importance The MOX protocol is comparable to the AHS-3 protocol, showing promise as an alternative to arsenical therapy for canine HW.
