Field clinical study evaluating the efficacy and safety of an oral formulation containing milbemycin oxime/praziquantel (Milbemax®, Novartis Animal Health) in the chemoprevention of the zoonotic canine infection by Dirofilaria repens

Abstract

BackgroundDirofilaria repens is the causative agent of subcutaneous dirofilariosis of dogs, other animals and humans. This nematode is transmitted by mosquitoes of Aedes, Anopheles and Culex genera. In dogs, the parasite may cause subclinical infection or cutaneous signs. Recently, D. repens has emerged and spread in different geographical areas, with an increase of cases in dogs and humans. Chemoprevention in dogs in endemic areas is the most reliable approach for controlling this infection. This paper describes a randomized, blocked and multicentric clinical field study investigating the efficacy of an oral, chewable formulation containing milbemycin oxime/praziquantel (Milbemax®, Novartis Animal Health) in the chemoprevention of subcutaneous dirofilariosis in dogs.MethodsThis study was conducted in endemic areas of Italy. A total of 249 dogs, at two sites, negative for D. repens, were allocated into two groups (i.e. Treated -T1 vs Untreated-T2) with a ratio of 1:1, and subjected to clinical visits and blood sampling once monthly until the end of the study. All blood samples were microscopically and genetically examined. Animals belonging to T1 group received a minimum target dose of 0.5 mg/kg bodyweight of milbemycin oxime and 5 mg/kg of praziquantel in commercial tablets (Milbemax®) according body weight once every 4 weeks. Animals of group T2 were not treated with Milbemax® but received, when necessary, specific parasiticide treatments. The study duration was 336 ± 2 days for each dog.ResultsA total of 219 dogs completed the study (i.e. 111 in T1 and 108 in T2), while 30 dogs (i.e. 13 in T1, 17 in T2) were withdrawn for a variety of reasons unrelated to administration of Milbemax®. The percentages of animals not showing microfilariae of D. repens were 100% (111 animals) in T1 and 94.7% (108 animals out of 114) in group T2. Milbemax® was shown to be safe in treated dogs.ConclusionsThe results of this study confirm that the monthly use of Milbemax® in dogs is effective and safe for the prevention of subcutaneous dirofilariosis in endemic areas.

Recent advances on Dirofilaria repens in dogs and humans in Europe

“…Finally, milbemycin oxime, another macrocyclic lactone, given orally once per month also proved to be effective in protecting dogs from subcutaneous dirofilariosis in endemic areas and may offer further chemoprevention option [277].…”

Evaluation of the Adulticidal Efficacy of Imidacloprid 10 %/Moxidectin 2.5 % (w/v) Spot-on (Advocate®, Advantage® Multi) against Dirofilaria repens in Experimentally Infected Dogs

“…None of the dogs treated monthly with the recommended dose became microfilaraemic, while 6 of 114 control dogs became infected. All positive dogs were successfully treated with milbemycin oxime, but the exact treatment protocol was not described (Di Cesare et al 2014). Oral and injectable formulations of moxidectin have shown preventive efficacy against D. repens in field studies (Rossi et al 2002(Rossi et al , 2004, and the efficacy of an injectable sustained-release formulation was confirmed in experimentally infected dogs (Genchi et al 2010).…”

Field Implementation of a Monthly Multi-Modal Prophylactic Strategy (Dinotefuran-Permethrin-Pyriproxyfen and Milbemycine Oxime-Praziquantel) Against Canine Vector-Borne Diseases in Corsica

“…In addition, the synergistic effect due to the simultaneous combination of a macrocyclic lactone and a parasiticide-repellent product provides better protection against CVBDs and in particular against MBHs, with respect to which both products are active. The combination milbemycin oxime/praziquantel, like other macrocyclic lactones, was designed to prevent dirofilarial infections in dogs [33]. DPP has a proven record of effectiveness in preventing a broad spectrum of vectors such as ticks, mosquitoes, sandflies, stable flies, fleas and triatomes [15][16][17], and this partly explains the successful prevention of the other CVBDs in the present study.…”