Immunological effects and productivity variation of red mite (Dermanyssus gallinae) on laying hens - Implications for egg production and quality

Red mite (Dermanyssus gallinae; De Geer, 1778) is currently one of the most detrimental ectoparasites in laying birds across several countries. Symptoms of D. gallinae infestation include reduction in production, poor egg quality, increased mortality and also a compromise to welfare. Feeding on its host for only short periods of time, the red mite spends the vast proportion of its short life-cycle hidden deep within the house substructure. For this reason, it is the preference of red mite to occupy free range or barn systems as opposed to caged, since a greater number of potential hiding places can be sought. A problem which will therefore be amplified within the EU with the impending ban on production in laying cages. This, in conjunction with concern over resistance to acaricides, toxicity risks and acaricide withdrawal, make control particularly problematic and financially draining for producers. Therefore alternative methods must be sought, such as vaccine development. However, in order for this to be achieved, an understanding of mite antigenicity must first be established. 
Thus, the purpose of this study was to assess immunological response of humeral antibodies to naturally occurring mite antigens, using enzyme-linked immunosorbent assay (ELISA) and SDS-PAGE. Antibodies were derived from egg yolk and blood sera which were collected from commercial laying farms across the UK with varying levels of red mite infestation and using different production systems (caged, barn and free range). In addition, mites were trapped and counted periodically so as to follow population dynamics over a flock lifespan in conjunction with a series of production measures (Laying percentage, eggs per bird per week, mortality and temperature). The results describe the effect of red mite infestation on production parameters, immunological response and the relationship between them.