Efficacy of afoxolaner or a combination of afoxolaner and milbemycin oxime against fleas, ticks, lice and/or intestinal nematodes in dogs naturally infested in two urban areas in Brazil

Infestations with fleas, ticks and intestinal nematodes are commonly identified in domestic dogs and have significant veterinary and public health importances. The study described in this manuscript was conducted to verify the natural parasitism of domestic dogs in two Brazilian regions, and to confirm the efficacy of the isoxazoline afoxolaner, formulated alone (NexGard®) or in combination with the macrocyclic lactone milbemycin oxime (NexGard Spectra®), for the control of fleas and ticks, and to confirm the efficacy of the afoxolaner/milbemycin oxime (MO) combination for the control of intestinal nematodes. This trial was conducted in Mato Grosso (MT) and Maranhão (MA) states, Center-West and Northeast region. Three hundred and forty-five (345) domestic dogs, 170 in MT and 175 in MA, infested with at least one of these parasites, were studied. Dogs were treated once and evaluated approximately two and four weeks later for ectoparasites, and two weeks later for intestinal nematodes. Approximately half (47.5%) of the dogs were infested with more than one parasite, more than one third (38.6%) with intestinal nematodes. All fleas were identified as Ctenocephalides felis, ticks as Rhipicephalus linnaei (previously defined as Rhipicephalus sanguineus s.l.) and intestinal nematodes eggs as Ancylostoma, Toxocara or Trichuris . In Maranhão, 11 dogs were also infested with the chewing louse Heterodoxus spiniger. Both products had a comparable efficacy against fleas (98.4% to 100%), ticks (96.9% to 100%) and lice (100%). The MO formulation had an efficacy of ≥ 97.8% against Ancylostoma , ≥ 94.7% against Toxocara and ≥ 97.7% against Trichuris. This study demonstrated a significant parasitic abundance in domestic dogs in two urban areas in Brazil, and confirmed a high efficacy of afoxolaner against fleas, ticks and lice and a high efficacy of MO against intestinal nematodes.