Abstract
BackgroundNorthern fowl mites (Ornithonyssus sylviarum) are obligate hematophagous ectoparasites of both feral birds and poultry, particularly chicken layers and breeders. They complete their entire life-cycle on infested birds while feeding on blood. Infestations of O. sylviarum are difficult to control and resistance to some chemical classes of acaricides is a growing concern. The contact susceptibility of O. sylviarum to a new active ingredient, fluralaner, was evaluated, as well as other compounds representative of the main chemical classes commonly used to control poultry mite infestations in Europe and the USA.MethodsSix acaricides (fluralaner, spinosad, phoxim, propoxur, permethrin, deltamethrin) were dissolved and serially diluted in butanol:olive oil (1:1) to obtain test solutions used for impregnation of filter paper packets. A carrier-only control was included. Thirty adult northern fowl mites, freshly collected from untreated host chickens, were inserted into each packet for continuous compound exposure. Mite mortality was assessed after incubation of the test packets for 48 h at 75% relative humidity and a temperature of 22 °C.ResultsAdult mite LC50 /LC99 values were 2.95/8.09 ppm for fluralaner, 1587/3123 ppm for spinosad, 420/750 ppm for phoxim and 86/181 ppm for propoxur. Permethrin and deltamethrin LC values could not be calculated due to lack of mortality observed even at 1000 ppm.ConclusionsNorthern fowl mites were highly sensitive to fluralaner after contact exposure. They were moderately sensitive to phoxim and propoxur, and less sensitive to spinosad. Furthermore, the tested mite population appeared to be resistant to the pyrethroids, permethrin and deltamethrin, despite not being exposed to acaricides for at least 10 years.
Highlights
Northern fowl mites (Ornithonyssus sylviarum) are obligate hematophagous ectoparasites of both feral birds and poultry, chicken layers and breeders
Two major ectoparasite species severely affect the poultry industry worldwide: the northern fowl mite, Ornithonyssus sylviarum, and the poultry red mite, Dermanyssus gallinae [1, 2]. Both mite species are obligate hematophagous parasites able to complete their life-cycles within about 1 week under optimal conditions [2,3,4]
Mite populations can become dense very quickly in commercial poultry facilities reducing hen performance and profitability [5, 6]. They differ mainly in that all stages of O. sylviarum mites live on the host fulltime, occupying and laying eggs in the fluffy feathers mostly of the vent region [1] (Fig. 1), while D. gallinae lives predominantly off-host, hidden in cracks and crevices, and comes out nocturnally to feed on the birds [2]
Summary
Northern fowl mites (Ornithonyssus sylviarum) are obligate hematophagous ectoparasites of both feral birds and poultry, chicken layers and breeders They complete their entire life-cycle on infested birds while feeding on blood. Two major ectoparasite species severely affect the poultry industry worldwide: the northern fowl mite, Ornithonyssus sylviarum, and the poultry red mite, Dermanyssus gallinae [1, 2] Both mite species are obligate hematophagous parasites able to complete their life-cycles within about 1 week under optimal conditions [2,3,4]. A complicating factor for both mite species is that they can persist without hosts for weeks and perhaps months in the environment [7, 8] Their very small size makes them a difficult target for spray treatments and subsequent disinfestation of poultry houses between flocks. These acaricidal sprays must penetrate the feather layer from under the birds (vent region) to treat O. sylviarum onhost, which make it difficult to spray birds in enrichedcage or cage-free systems
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