Early onset of pre-lethal effects of lotilaner (Credelio®) on Amblyomma americanum ticks on experimentally infested dogs

Parasites & Vectors

Madeline C. Burke¹  Martha J. Wenger¹  Lauren Miller¹  Kathryn E. Reif¹  Brian H. Herrin¹  Sydnie Reeves¹  Debra Ritchie¹  Vicki Smith¹  Cameron Sutherland¹  Makaela Hedberg¹  Casey Locklear²  Todd M. Kollasch²  Anthony J. Rumschlag²  Livvy Jones³  William G. Ryan⁴ 

[1] Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA;Elanco Animal Health Inc, 2500 Innovation Way, Greenfield, IN, USA;Ellen Jones, Manhattan, KS, USA;Ryan Mitchell Associates LLC, 16 Stoneleigh Park, Westfield, NJ, USA;

关键词: Acaricide;    Amblyomma americanum;    Canine;    Credelio;    EthoVision XT;    Isoxazoline;    Lone star tick;    Lotilaner;    Motility;   

DOI  :  10.1186/s13071-021-04817-z

来源: Springer

【 摘 要 】

BackgroundThe speed with which acaricides paralyze and kill ticks is relevant to impeding pathogen transmission. The objective of this study was to assess early-onset lotilaner effects on the motility and weights of Amblyomma americanum ticks collected from treated dogs.MethodsTwelve healthy dogs were randomized between two groups to receive either lotilaner (Credelio®) on Day 0 or to be sham treated. On Day 7, 25 male and 25 female A. americanum were placed under bandages, two on each flank of each dog. After 30 or 45 min, all unattached ticks were removed and T = 0 was set. At T = 2, 4, 8 and 24 h post attachment, 5 attached ticks removed from each bandage on each dog were weighed, assessed by blinded observers for righting ability and movement recorded.ResultsAfter the infestation period significantly fewer treated than control dogs had 20 ticks attached (50.0% versus 91.7%, P = 0.0015). At 24 h post attachment, mean weights of ticks from treated dogs (males 1.69 mg; females 2.72) were significantly less than ticks from controls (males 2.66 mg; females 4.67) (Pmale = 0.0002; Pfemale < 0.0001). Mean tick weights from the treated group were significantly lower at 24 h than at earlier time points (Pmale < 0.0307; Pfemale = 0.0021). At 4 and 8 h, significantly fewer ticks from treated (14.3%, 0.0%, respectively) than from control dogs could right (73.3%, 70.0%) (P4h < 0.0001; P8h = 0.0024) (at 24 h, all ticks from treated dogs were dead), and distance moved was significantly less at all time points (P2h = 0.0413; P4h, P8h < 0.0001). Mean and maximum velocity of ticks from treated dogs were significantly lower, relative to controls, at 4 and 8 h (P ≤ 0.0001). Within the treated group, collected ticks had significantly lower mean and maximum velocities at 4 and 8 h compared to 2 h (Pmean < 0.0042; Pmax < 0.0194).ConclusionThe observed changes indicate that lotilaner may disrupt tick attachment. In ticks that attached, a progressive impairment of neuromuscular processes began within 2 h. Those irreversible changes could substantially reduce the risk of pathogen transmission from tick to host.

【 授权许可】

CC BY