E. Castilla-Castaño1, A. Vischi2, C. Navarro3, LA. Lecru1, S. Pradier2, MC Cadiergues1

1 - Dermatology Unit, Toulouse Veterinary School, 23 chemin des Capelles 31076 Toulouse cedex 3, France 2- Equine Unit, Toulouse Veterinary School, 23 chemin des Capelles 31076 Toulouse cedex 3, France 3- Companion Animal Medical Department - Virbac group 13ème rue - LID – 06511 Carros, France

AIM OF THE STUDY AIM OF THE STUDY

To evaluate the clinical efficacy and the tolerance of a deltamethrin 10 mg/mL pour-on, as a single application, on lice burden and associated clinical lesions in horses naturally infected by Damalinia equi in south-west of France. This study was designed as a single treatment, open-controlled study.

SUMMARY SUMMARY

This study evaluated the efficacy and the tolerance of a 10 mg/mL deltamethrin-based pour-on solution (Deltanil®; Virbac, Carros, France) in 11 horses with natural Damalinia equi infestation. Seven horses received 10 mL of the solution from the mane to the tail head on D0. Four horses, living separately, served as non-treated controls. Lice burden was recorded by parting the coat bilaterally, over the neck, shoulder, withers, barrel, buttock and quarter, and counting the number of live parasites. Lesional score was based on alopecia, crusts, papules/pustules, nodules/plaques, scales and wounds, each assessed on a 0-3 scale on the same regions. Evaluation was performed on D0 and subsequently weekly until D56 in treated horses and on D0 and D56 in control horses. The response to treatment was assessed as the change from baseline to each examination day for parasite and lesional scores. No adverse event was recorded. In control horses, parasite and lesional scores were maintained on D56, mean [SD]: D0 46 [8.5], 3 [0] and D56 51 [15.6], 3 [0]; respectively. Parasite scores of the treated horses were reduced by 98% on D7 and 100% from D15 to D56 (mean [SD]: D0 44 [58.4]). Lesional score in treated horses was reduced by 24%, 82%, 47%, 91%, 96%, 93%, 93% and 100% on D7, 15, 21, 28, 35, 42, 50 and 56, respectively (mean [SD]: D0 3.1 [1.8]).

A single application of the 10mg/mL deltamethrin preparation was effective and safe in the treatment of lice infestation in these horses.

MATERIAL AND METHODS MATERIAL AND METHODS

Animals: Seven horses naturally infested with D. equi living in outdoor conditions. Four horses living separatly in the same geographic area served as non-treated controls on days 0 and 56.

Product: 10 mg/mL deltamethrin based-pour-on (Deltanil® ; Virbac, Carros, France) at the single dose of 10 ml per animal from the mane to the tail head at D0 after parasite and lesional score evaluations.

Parasite score was recorded according to the European Medicines Agency’s method for ruminants (EMEA/CVMP/625/03 final) parting the coat bilaterally, over the neck, shoulder, withers, barrel, buttock and quarters (fig 1) and counting the number of live parasites at D7, 15, 21, 28, 35, 42, 50 and 56.

Lesional score was based on alopecia, crusts, papules/pustules, nodules/plaques, scales and wounds, each assessed on a 0-3 scale on the same regions, on the same days of parasite score, always performed by the same two persons.

Data analysis The response to treatment was assessed as the change from baseline to each examination day for parasite and lesional scores.

Fig. 1: anatomic regions where scoring was performed

RESULTS RESULTS

Me

an

no

. of

lice

± s

d

days

Parasite scores of the treated horses were reduced by 98% on D7 and 100% from D15 to D56 (mean [SD]: D0 44 [58.4])

Parasite scores from D0 to D56

days

Lesional scores from D0 to D56

Lesional score in treated horses was reduced by >90% from D28 to D56 (mean [SD]: D0 3.1 [1.8]).

CONCLUSION CONCLUSION

A single application of the 10mg/mL deltamethrin preparation was effective and safe in the treatment of lice infestation in these horses.

D0

D0

D56

D56