Prevalence of mites and their impact on laying hen (Gallus gallus domesticus) farm facilities in Egypt, with an analysis of deltamethrin residues in eggs and tissue.

This study was carried out on six laying hen farms, three mite-infested and three mite-free at Dakahlia and Damietta governorates in Egypt to demonstrate: (i) prevalence of different species of mites on laying hen farms; (ii) effects of mite infestation on chicken health and production; (iii) efficacy of deltamethrin (DMT) on treatment of mite infestation and (iv) residues of DMT in eggs and meat. The results showed that 12 mite species were detected in the mite-infested farms, this is the first record in Egypt, and that Dermanyssus gallinae was the highest identified species from 295 (40.9%) of 720 samples. There was a significant effect (P ≤ 0.05) of mites on the mortality %, feed consumption, egg production % and the tested haematological parameters. DMT had no impact on production performance, while transient respiratory signs post-spraying were recorded. The mites induced severe skin lesions. Egg samples showed the highest residue levels of DMT, followed by muscle and skin at P ≤ 0.05. It can be concluded that the mite species, as a first record, had a deleterious impact on the performance of the Egyptian laying hen farm facilities. Moreover, that DMT (Butox® 50 EC, Intervet Co., France) spraying was ineffective by one-time application, every 1 or 2 months in mite-infested laying hen farms, particularly when heavily infested. Furthermore, DMT residues in laying hen eggs and tissue should be considered to avoid the potential risk for humans.