In vitro, off-host, rearing of the poultry red mite to supply parasites for development of new control methods

Infestation of hen houses with poultry red mites is a major animal welfare and economic problem for the egg-producing industry internationally and multiple groups worldwide are engaged in the development of new control methods for this parasite. Poultry red mites are parasites which need to feed on a bird's blood to survive, develop and reproduce. To supply mites for any research programme, donor hens must be infested with the parasite to provide sufficient numbers of mites for subsequent laboratory or field studies. The aim of the current proposal is to replace the use of mite-infested hens as a source of parasite material by establishing a laboratory colony of mites, using a novel feeding method designed in our group, which is both sustainable for the routine culturing of mites and can be scaled-up for the production of the large numbers of mites required for trials when required. Through a series of preliminary experiments in our laboratory, we have established that poultry red mites will feed on goose blood through a disposable synthetic skin-like membrane. The blood is donated by live geese maintained under very high welfare standards in a dedicated blood-donor flock. Geese are particularly suited to be blood donors for this task as they can supply a much greater volume of blood than hens (approximately 30 times as much in a single donation). We have calculated that, by using this system, we could reduce the number of hens used for the maintenance of poultry red mites by 90% per year and, in addition, increase welfare standards by removing the need for hens to be continuously infested with the parasites for prolonged periods. By following a series of 3 Objectives we will optimise this system for routine mite culturing and scaling up for large numbers of mites required for larger studies:
Objective 1 will establish the optimal conditions for storing goose blood and for feeding poultry red mites on this blood;
Objective 2 will determine if lab-reared mites behave in the same way as field-caught mites when exposed to a hen;
Objective 3 will optimise mite housing and feeding for sustainable expansion of colony numbers.

Infestation of hen houses with poultry red mites (Dermanyssus gallinae) is a major animal welfare and economic problem for the egg-producing industry internationally and multiple groups worldwide are engaged in the development of new control methods for this parasite. Because D. gallinae is an obligate blood-feeding parasite, to supply mites for any research programme, donor hens must be infested with the parasite to provide sufficient numbers of mites for subsequent laboratory or field studies. The aim of the current proposal is to replace the use of mite-infested hens as a source of parasite material by establishing a laboratory colony of mites, using a novel in vitro feeding methodology designed in our group, which is both sustainable for the routine culturing of mites and scalable for the production of the large numbers required for trials (e.g. vaccine studies or the development of novel acaricides) when required. Through a series of preliminary experiments in our laboratory, we have established that poultry red mites will feed, off-host, in an in vitro feeding device containing goose blood which is derived from our donor flock of geese. Geese are particularly suited to be blood donors for this task as they can supply a much greater volume of blood per procedure (bleed) than hens (approximately 30-fold). By following a series of 3 Objectives we will optimize this system for routine mite culturing and scaling up for large numbers of mites required for larger studies:
Objective 1 will establish optimal mite feeding protocols to maintain mite colonies long term through an analysis of multiple nutritional and environmental parameters;
Objective 2 will determine if lab-reared mites behave in the same way as field-caught mites when exposed to a host;
Objective 3 will optimise mite housing and feeding for sustainable expansion of colony numbers.