Long-term efficacy of a drug-loaded polymeric device on lice-infested laying hens

CEBALLOS, L; DOMINGUEZ , P; ALVAREZ, L.

Congreso; Waavp; 2023

Lice infection is an important health problem in aviculture, especially in free-ranged laying hens. However, few specific treatments intended to lice control in aviculture are available. The goal of the current work was to evaluate the long-term efficacy of a drug-loaded polymeric device in lice-infected laying hens. Since lice are obligate parasites, the medicated device was challenged in different groups of lice-infested hens. For that, a cypermethrin/deltamethrin-based polymeric device (ring shape) was placed in the shank of laying hens (n= 6, Group A) infected with lice (Goniocotes gallinae), which shared the pen with other infected non-treated hens (n= 40). Lice were counted pre-treatment, and at different times post-treatment including 1, 4, 7, 14, 21, and 30 days. At this time, ring polymeric devices were removed and placed in a different group (Group B) of lice-infected laying hens. A similar scheme of counting lice to that described for Group A was carried out in Group B. After the month of treatment, the rings were placed in a new group (Group C) of lice-infected hens, and the lice count was repeated as described. Overall, the control of the lice-killing effect of the device was monitored for 3 months. No systemic or local adverse effects were observed in treated animals. The device reached 100% efficacy at 1 day post-treatment in Group A and at 4 days post-treatment in Groups B and C. In all groups, the animals remained free of lice until the time the ring was removed to be placed in a new group of infested hens. Three months after continuous use of the device, all treated animals (Group C) were kept free of lice. The results obtained show that the medicated device was effective for the long-term control (three months) of lice in laying hens.