Sources of northern fowl mite (Ornithonyssus sylviarum) infestation in Ontario egg production facilities

In the poultry industry, northern fowl mites are generally thought to survive poorly once they have left the bird. However, several researchers have found mites infesting equipment or surviving off-host for up to 2 wk. Our work demonstrated that large numbers of mites can be found on cage equipment in poultry houses, and if an acaricide application is not a part of the cleanout program at the end of the production cycle, there is a good chance that mites will survive to infest the next flock. A province-wide inspection of 16- to 18-wk-old pullets indicated that a new mite infestation was more likely to originate from the production facility than the pullet rearing facility. However, a previous investigation found a pullet flock infested with mites, indicating that pullet facilities were not completely free of responsibility. In order to reduce the chance of future infestations of northern fowl mites, it is necessary to incorporate an acaricidal treatment to prevent them from surviving cleanout procedures in egg production facilities and, if necessary, pullet rearing facilities.