Impact of Poultry Red Mite (Dermanyssus gallinae) Infestation on Blood Parameters of Laying Hens

The poultry red mite Dermanyssus gallinae is commonly acknowledged as a serious biological threat to global poultry breeding. This is mostly because of the inefficiency of acaricidal treatments of poultry houses, which does not eliminate the mite population, only constrains it. However, the impact of D. gallinae on poultry welfare is poorly characterized. The biochemical and cytological characteristics of infection are limited mainly to anaemia, decreased levels of triglycerides in the blood and eosinophilia. For the first time, we report the adverse effects of D. gallinae infestation of industrial poultry houses on the functional state of poultry livers. Treatment of poultry houses with acaricidal powder preparation, Wooran-dust 0.7%, containing synthetic pyrethroids (permethrin, S-fenvalerate and tetramethrin), led to the elimination of the mite population and resulted in normalization of most of the haematological and biochemical blood parameters (haemoglobin, erythrocytes, neutrophils, basophils, lymphocytes and AST). Increased eosinophils and ALT were the only indicators of infection in the blood of laying hens, and they remained above normal range until the 22nd day after the beginning of treatment with the acaricidal agent.