Molecular characterisation and phylogenetic inference of, Dermanyssus gallinae within an European framework. Cytochrome c oxidase subunit I (COI) diversity in the poultry red mite

The poultry red mite (Dermanyssus gallinae), an obligatory blood feeding ectoparasite, is primarily associated with laying hens where it is predicted to incur losses of ~€231 million per annum from European farmers. Moderate to high infestation levels result in negative impacts on hen welfare, including an increase in cannibalism, irritation, feather pecking, restlessness, hen mortality and anaemia. Acaricides are currently the prevailing method of population control for D. gallinae, although widespread resistance against some classes of acaricide has been reported across the poultry industry. The development of resistance has highlighted a growing need for research into alternative control methods, including the development of a suitable and effective vaccine to protect chickens against D. gallinae. Understanding the genetic structure of D. gallinae populations can improve management of acaricide resistance and the sustainability of future vaccines, but limited data is available. The primary objective of this study was to provide molecular characterisation of D. gallinae isolates from Europe, targeting the cytochrome c oxidase subunit 1 (COI) gene, to gain further insight into population structure and genetic diversity. Dermanyssus gallinae isolates were collected from the United Kingdom, the Netherlands, Belgium, France, Portugal, Italy, Czech Republic, Romania, Croatia, Albania, Greece, Turkey and Denmark. Genomic DNA was extracted from individual adult D. gallinae mites and a 737bp fragment was amplified and sequenced. Phylogenetic analysis revealed three main haplogroups divided into six sub-haplogroups. Analysis demonstrated both inter- and intra-country variation across Europe, which could be the result of differential control measures and husbandry practices.