A nonexhaustive overview on potential impacts of the poultry red mite (Dermanyssus gallinae) on poultry production systems.

Abstract

The poultry red mite (PRM) (Dermanyssus gallinae) is a worldwide problem for the poultry production industry. Prevalence rates of more than 80% are common in many countries (Sparagano et al., 2009; Tomley and Sparagano, 2018). Complete development of D. gallinae, from egg to adult through one larval stage and two nymphal stages, typically occurs over 2 weeks. They usually feed for short periods and retrieve in cracks and crevices to digest blood contrary to other poultry mites. Economic costs associated with both control and production losses due to D. gallinae have been estimated at €130 million per year for the European Union egg industry. There is a relationship between D. gallinae infestation and hen mortality; some reports record a 10-fold increase in death rates following severe infestation in Romania (Cosoroaba, 2001). Although causal factors may vary, in extreme cases D. gallinae numbers may be so high that hens become severely anemic, with mortality resulting from exsanguination. At a sublethal level, mite feeding may result in significant stress to hens, causing an increase in circulating corticosterone and adrenaline and a decrease in β- and γ-globulins. Bird sleep patterns can be disrupted by the need for increased preening, and changes in head-scratching and feather-pecking behavior could also be seen. Increases in aggressive feather-pecking and cannibalistic behaviors have been reported. These mites can survive for weeks if not months without a blood meal and can therefore reappear between flocks. As blood feeders, PRMs could induce anemia with economic losses related to smaller egg size, less eggs per hen per year, and higher mortality. A recent report in Belgium followed various production parameters for fluralaner-treated bird groups compared to control groups, highlighting the positive impact of such treatment (Sleeckx et al., 2019). These mites can harbor key symbionts needed for their survival (de Luna et al., 2009) and can be responsible for the transmission of bacterial and viral diseases such as Salmonella (Valiente Moro et al., 2007; Hamidi et al., 2011; Sylejmani et al., 2016), Avian Influenza (Sommer et al., 2016), Coxiella burnetii, and Borrelia burgdorferi (Raele et al., 2018) which can also decimate flocks in their own rights (Sparagano et al., 2014).