Authors
T Kuester3; D Price1; A J Nisbet1; O Oines2; D P Blake3; F Tomley3; 1 Moredun Research institute; 2 Norwegian Veterinary Institute, Norway; 3 Royal Veterinary College Discussion
Dermanyssus gallinae is the most important ectoparasite affecting egg-laying chickens. Infested birds may suffer from anaemia, dermatitis, weight loss and decreased egg production. The scarcity of effective pesticides has contributed to a significant problem for the layer industry. Commercially available acaricides are not effective in the control of poultry red mite infestations due in part to increased parasite resistance. Additionally, acaricide use is gradually being discontinued as a consequence of public awareness and legislation against chemical residues on food products, and chemical release and accumulation in the environment. The development of an effective vaccine can decrease the occurrence and impact of D. gallinae, thereby improving the general health and welfare of layers without the use of acaricides. Transfection vectors have been developed for genetic complementation of Eimeria tenella, prompting the notion that live-attenuated coccidial parasites could be used as effective vectors for the oral delivery of heterologous vaccine antigens to poultry. In cooperation with two PARAGONE partners we propose to compare the delivery of a defined antigen (cathepsine D1) in three systems, namely DNA vaccination, recombinant protein formulation in montanide and cytosolic, secreted, or membrane-tethered antigen expressed by the Eimeria vector. The immune responses, efficacy, and endurance of the effect of vaccination are being currently investigated. 
