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The hematophagous arthropod, Dermanyssus gallinae (Poultry red mite, PRM) can cause remarkable economic losses in the poultry industry across the globe. Although overall composition of endosymbiotic bacteria has been shown in previous studies, how farm habitats influence the microbiome remains unclear. In the present study, we compared the bacterial communities of D. gallinae populations collected from the cage and free-range farms using next-generation sequences targeting the V3-V4 hypervariable region of the 16S rRNA gene. The QIIME2 pipeline was followed in bioinformatic analyses. Proteobacteria represented a great majority of the total bacterial community of D. gallinae from both farming systems. More specifically, Bartonella-like bacteria (40.8%) and Candidatus Cardinium (21.5%) were found to be predominant genera in free-range and cage rearing systems, respectively. However, the microbiome variation based on farming systems was not statistically significant. In addition, the presence of the five common endosymbiotic bacteria (Wolbachia, Cardinium, Rickettsiella, Spiroplasma, and Schineria) was screened in different developmental stages of D. gallinae. Cardinium was detected in all developmental stages of D. gallinae. On the other hand, Wolbachia and Rickettsiella were only found in adults/nymphs, but neither in the eggs nor larvae. To our knowledge, this study provides the first microbiome comparison at genus-level in D. gallinae populations collected from different farm habitats and will contribute to the knowledge of the biology of D. gallinae. [ABSTRACT FROM AUTHOR]

In the present study, the acaricidal effects of cold atmospheric pressure plasma treatment on poultry red mites of different developmental stages have been investigated under laboratory conditions using a dielectric barrier discharge system. A total of 1890 poultry red mites and 90 mite eggs, respectively, were exposed to the plasma under various parameter settings with a single plasma pulse generated using the gas mixture of the ambient air at atmospheric pressure. The results showed that all developmental stages of the poultry red mite could be killed by cold atmospheric pressure plasma treatment. Plasma exposure to mite eggs resulted in a complete 100% hatch inhibition regardless of the parameter settings. Post-exposure mortality rates of larvae, nymphs and adults showed significant differences after utilization of plasma at 10 W for 1.0 s. In addition, the mortality rate increased with progressing time after plasma exposure. An average mortality rate of 99.7% was observed after 12 h in all mites exposed to plasma, regardless of the selected plasma parameter, developmental stage, and nutritional status of the mites. Cold atmospheric pressure plasma has an acaricidal effect on all developmental stages of Dermanyssus gallinae, suggesting that it could be developed to an effective method for the control of poultry red mites in laying hen husbandry. [ABSTRACT FROM AUTHOR]

Dermanyssus gallinae (poultry red mite, PRM) is a main ectoparasite of poultry that represents a serious economic threat to all farming systems, including cages and backyard flocks. In recent years, economic losses associated with this ectoparasite have progressively increased, mainly because of the lack of information regarding its population dynamics and appropriate control methods. In this study, we used a modified monitoring method to examine the in-house factors affecting the population density of D. gallinae. PRMs have been found in all poultry houses examined in Turkey. The largest population was detected in the front and back parts of the middle rows in cage systems as well as in perches in backyard systems. Relative humidity, light, and temperature might be the most affecting factors on the mite distribution inside the poultry houses. Besides, the mite populations are influenced mainly by the last (chemical) treatment date and the construction materials of the building. Dermanyssus gallinae were found to be the most dominant mite species (98.9%), followed by Cheyletus sp. (Cheyletidae); also some Acaridae (Tyrophagus spp.) and Oribatida were identified. Hence, further research on Cheyletus sp. is required to elucidate their predatory potential and develop future control strategies. This study contributes to understanding the PRM population behavior in poultry houses as well as their monitoring and control methods, which are key components in the appropriate application of integrated pest management programs. [ABSTRACT FROM AUTHOR]

The poultry red mite, Dermanyssus gallinae, is a blood-feeding parasite of layer hens and a potential vector of several avian infectious agents. High infestation with D. gallinae in layer farm buildings could result in economic losses, and the mites may act as a reservoir of avian pathogens within farms. This study aimed to assess the prevalence of D. gallinae in layer farm buildings in Korea and to investigate avian pathogens in the collected mites. The mite samples were collected from 36 Korean layer farm buildings on 21 farms nationwide. Information obtained from each farm building included the flock size, flock age, methods for controlling D. gallinae, and cleaning status. Association between these variables and the population density of D. gallinae was analyzed. Additionally, the presence of 10 avian pathogens was assessed using DNA samples from mites collected in 16 farm buildings. The prevalence of D. gallinae was 75% at the farm building level (90.5% at the farm level). Repetitive cleaning procedures for each building were significantly related with the mite infestation level, and the most influential factor for determining the mite population in the layer farm buildings. In the 16 DNA samples, we detected avian pathogenic Escherichia coli (n = 6), wild-type fowlpox virus (n = 3), wild-type Marek's disease virus (n = 2), chicken anemia virus (n = 1), and fowl adenovirus (n = 1). These findings suggest that repetitive cleaning procedures for the layer farm buildings could decrease the numbers of D. gallinae which may transmit avian pathogens within the farm. [ABSTRACT FROM AUTHOR]

The poultry red mite Dermanyssus gallinae is commonly acknowledged as a serious biological threat to global poultry breeding. This is mostly because of the inefficiency of acaricidal treatments of poultry houses, which does not eliminate the mite population, only constrains it. However, the impact of D. gallinae on poultry welfare is poorly characterized. The biochemical and cytological characteristics of infection are limited mainly to anaemia, decreased levels of triglycerides in the blood and eosinophilia. For the first time, we report the adverse effects of D. gallinae infestation of industrial poultry houses on the functional state of poultry livers. Treatment of poultry houses with acaricidal powder preparation, Wooran-dust 0.7%, containing synthetic pyrethroids (permethrin, S-fenvalerate and tetramethrin), led to the elimination of the mite population and resulted in normalization of most of the haematological and biochemical blood parameters (haemoglobin, erythrocytes, neutrophils, basophils, lymphocytes and AST). Increased eosinophils and ALT were the only indicators of infection in the blood of laying hens, and they remained above normal range until the 22nd day after the beginning of treatment with the acaricidal agent. [ABSTRACT FROM AUTHOR]

The poultry red mite, Dermanyssus gallinae, represents a key threat for the poultry industry worldwide. The control of D. gallinae is mainly achieved by continuous applications of acaricides. However, the fast-growing development of resistance, and the strict laws concerning chemicals admitted for treatments on food animals, highlighted the importance of alternative control tools. Here, we explored the potential of Artemisia sieberi essential oil against D. gallinae. In this study, the A. sieberi essential oil was analyzed using GC and GC-MS. The oil toxicity through contact and fumigant assays on adult mites was evaluated. The oil repellent activity was assessed on adult mites over different time intervals. Lastly, the residual toxicity of various doses of the oil was evaluated on D. gallinae until 14 days post treatment. GC and GC-MS showed that the oil was rich in α-thujone (31.5%), β-thujone (11.92%), camphor (12.3%), and 1,8-cineole (10.09%). Contact toxicity on adult mites showed 50% lethal concentration (LC), LC, and LC of 15.85, 26.63, and 35.42 μg/cm, respectively. In fumigant assays, the oil was toxic on D. gallinae, and mortality was significantly higher in open containers over closed ones, underlining the key role of highly volatile constituents. Repellent assays showed that after 24 h from the treatment, all doses of the A. sieberi essential oil led to significant repellent activity over the control, except for 2 μg/cm. After 48 h, A. sieberi essential oil tested at all doses led to significant repellent activity, if compared to the control. Residual toxicity assays showed that time exposure and concentration tested had a significant impact on mite mortality after 1, 2, 5, and 7 days from the treatment. Notably, mortality remained significantly higher over the control for 7 days after spraying with oil at 2%. Further field assays with selected molecules from the A. sieberi essential oil are ongoing, testing them in synergistic blends, as well as in microencapsulated formulations. [ABSTRACT FROM AUTHOR]

For integrated pest management (IPM) programs to be maximally effective, monitoring of the growth and decline of the pest populations is essential. Here, we present the validation results of a new automated monitoring device for the poultry red mite ( Dermanyssus gallinae), a serious pest in laying hen facilities world-wide. This monitoring device (called an 'automated mite counter') was validated in experimental laying hen cages with live birds and a growing population of D. gallinae. This validation study resulted in 17 data points of 'number of mites counted' by the automated mite counter and the 'number of mites present' in the experimental laying hen cages. The study demonstrated that the automated mite counter was able to track the D. gallinae population effectively. A wider evaluation showed that this automated mite counter can become a useful tool in IPM of D. gallinae in laying hen facilities. [ABSTRACT FROM AUTHOR]

To assess their potential to control poultry red mites ( Dermanyssus gallinae), we tested selected predaceous mites ( Androlaelaps casalis and Stratiolaelaps scimitus) that occur naturally in wild bird nests or sometimes spontaneously invade poultry houses. This was done under laboratory conditions in cages, each with 2-3 laying hens, initially 300 poultry red mites and later the release of 1,000 predators. These small-scale tests were designed to prevent mite escape from the cages and they were carried out in three replicates at each of three temperature regimes: 26, 30 (constant day and night) and 33-25 °C (day-night cycle). After 6 weeks total population sizes of poultry red mites and predatory mites were assessed. For the temperature regimes of 26 and 33/25 °C S. scimitus reduced the poultry red mite population relative to the control experiments by a factor 3 and 30, respectively, and A. casalis by a factor of 18 and 55, respectively. At 30 °C the predators had less effect on red mites, with a reduction of 1.3-fold for S. scimitus and 5.6-fold for A. casalis. This possibly reflected hen manure condition or an effect of other invertebrates in the hen feed. Poultry red mite control was not negatively affected by temperatures as high as 33 °C and was always better in trials with A. casalis than in those with S. scimitus. In none of the experiments predators managed to eradicate the population of poultry red mites. This may be due to a prey refuge effect since most predatory mites were found in and around the manure tray at the bottom of the cage, whereas most poultry red mites were found higher up in the cage (i.e. on the walls, the cover, the perch, the nest box and the food box). The efficacy of applying predatory mites in the poultry industry may be promoted by reducing this refuge effect, boosting predatory mite populations using alternative prey and prolonged predator release devices. Biocontrol success, however, will strongly depend on how the poultry is housed in practice (free range, cage or aviary systems) and on which chemicals are applied to disinfect poultry houses and to control other pests. [ABSTRACT FROM AUTHOR]

Nestling development and long-term survival in many bird species depend on factors such as parental feeding, time of breeding and environmental conditions. However, little research has been carried out on the effect of ectoparasites on nestling development, and no research on the impact of the trophic structure of arthropods inhabiting the nest (combined effects of ectoparasitic mites and predatory mites feeding on ectoparasites). We assess nestling development of European Starlings ( Sturnus vulgaris) in relation to the number of parasitic mites Dermanyssus gallinae (DG, a blood-sucking mite) and their predators, i.e. Androlaelaps casalis (AC), both dominant species of nidicolous arthropods in Starling nests. DG densities were not associated with nestling body mass or tarsus length during development (10 and 17 days of age), which contradicts our expectation that parasitic mites negatively influence growth. Furthermore, an increase in AC densities was associated with a significant decrease in body mass (not tarsus length) later during nestling development (at day 17-a proxy for nestling age-but not at day 10). The latter seems counterintuitive, but not when the inherent density-dependent delays in Lotka-Volterra predator-prey interactions are taken into account: a high density of predatory mites (AC) always arises after an increase of prey mites (DG). Thus, the high density of predatory mites indicates a preceding peak density of parasitic mites. Clearly, this explanation requires insight in the trophic structure of mites inhabiting Starling nests and bird nests in general. We conclude that multitrophic interactions (between predator, parasite and host) in nests should not be ignored when assessing nestling development. [ABSTRACT FROM AUTHOR]

The vector potential of the poultry red mite, Dermanyssus gallinae De Geer (Acari: Dermanyssidae), in relation to chicken erysipelas was investigated under experimental conditions. Chickens were inoculated intramuscularly with the bacterium Erysipelothrix rhusiopathiae, and mites were allowed to feed on the inoculated chickens for 5 days. After 20 days of starvation, the mites were allowed to feed on healthy chickens to enable transmission of bacteria. Blood samples were collected from the birds and analysed for the presence of E. rhusiopathiae, and ELISA tests were performed for seropositivity. The internal presence of E. rhusiopathiae in the mites after feeding of inoculated birds was also investigated. It could not be demonstrated that mites take up and transmit E. rhusiopathiae under the experimental conditions described. However, since there are case reports as well as other in vitro studies indicating the potential of D. gallinae to act as a reservoir and potential vector for infections agents, we cannot exclude the possibility that the red poultry mite transmits E. rhusiopathiae between chickens under field conditions. [ABSTRACT FROM AUTHOR]

Infestations with ectoparasitic poultry red mites (Dermanyssus gallinae) pose an increasing threat to poultry health and welfare. Because of resistance to acaricides and higher scrutiny of poultry products, alternative and environmentally safe management strategies are warranted. Therefore, we investigated how volatile cues shape the behavior of D. gallinae and how this knowledge may be exploited in the development of an attract-and-kill method to control mite populations. A Y-tube olfactometer bio-assay was used to evaluate choices of mites in response to cues related to conspecific mites as well as related to their chicken host. Both recently fed and starved mites showed a strong preference (84 and 85%, respectively) for volatiles from conspecific, fed mites as compared to a control stream of clean air. Mites were also significantly attracted to 'aged feathers' (that had remained in the litter for 3-4 days), but not to 'fresh feathers'. Interestingly, an air stream containing 2.5% CO2, which mimics the natural concentration in air exhaled by chickens, did attract fed mites, but inhibited the attraction of unfed mites towards volatiles from aged feathers. We conclude that both mite-related cues (aggregation pheromones) and host-related cues (kairomones) mediate the behavior of the poultry mite. We discuss the options to exploit this knowledge as the 'attract' component of attract-and-kill strategies for the control of D. gallinae. [ABSTRACT FROM AUTHOR]

This study investigated the endosymbiotic bacteria living inside the poultry red mite collected from five samples of one commercial farm from the UK and 16 farms from France using genus-specific PCR, PCR-TTGE and DNA sequencing. Endosymbiotic bacteria are intracellular obligate organisms that can cause several phenotypic and reproductive anomalies to their host and they are found widespread living inside arthropods. The farm sampled from the UK was positive for bacteria of the genera Cardinium sp. and Spiroplasma sp. From France, 7 farms were positive for Cardinium sp., 1 farm was positive for Spiroplasma sp., 1 farm was positive for Rickettsiella sp. and 2 farms were positive for Schineria sp. However, it was not possible to detect the presence of the genus Wolbachia sp. which has been observed in other ectoparasites. This study is the first report of the presence of endosymbionts living inside the poultry red mite. The results obtained suggest that it may be possible that these bacterial endosymbionts cause biological modifications to the poultry red mite. [ABSTRACT FROM AUTHOR]

Dermanyssus gallinae (De Geer), the poultry red mite, is a blood-feeding ectoparasite that infests many bird species. We have used an in vitro feeding assay to allow the identification of protective D. gallinae antigens that may have potential as vaccine candidates. Homogenised mites were extracted sequentially with PBS, Tween 20, Triton X100 and urea giving four protein fractions. Five experimental groups of Lohmann Brown hens were used to generate antibodies; four groups were injected with one of each of the protein fractions in QuilA adjuvant and a control group was injected with adjuvant only. Booster injections were administered 2 and 4 weeks after initial immunisation. Eggs were collected throughout the experiment and soluble IgY antibodies were extracted from a pool of egg yolks collected at week six post-injection. Western blots, performed using post vaccination antibodies from test and control groups, revealed a strong antibody response against a range of injected proteins. Fresh chicken blood, supplemented with antibodies raised against these protein fractions, was fed to mites in an in vitro feeding assay in order to determine whether the antibodies had an anti-mite effect. Although there was variability in the numbers of feeding mites, it was found that the strongest anti-mite effect was seen with the PBS protein fraction, which had a cumulative average mortality of 34.8% 14 days after feeding compared with 27.3% for the control group (P = 0.043). [ABSTRACT FROM AUTHOR]

The poultry red mite, Dermanyssus gallinae, is currently a significant pest in the poultry industry in Europe. Biological control by the introduction of predatory mites is one of the various options for controlling poultry red mites. Here, we present the first results of an attempt to identify potential predators by surveying the mite fauna of European starling (Sturnus vulgaris) nests, by assessing their ability to feed on poultry red mites and by testing for their inability to extract blood from bird hosts, i.e., newly hatched, young starlings and chickens. Two genuine predators of poultry red mites are identified: Hypoaspis aculeifer and Androlaelaps casalis. A review of the literature shows that some authors suspected the latter species to parasitize on the blood of birds and mammals, but they did not provide experimental evidence for these feeding habits and/or overlooked published evidence showing the reverse. We advocate careful analysis of the trophic structure of arthropods inhabiting bird nests as a basis for identifying candidate predators for control of poultry red mites. [ABSTRACT FROM AUTHOR]

The results of this study suggest that certain eucalyptus essential oils may be of use as an alternative to synthetic acaricides in the management of the poultry red mite, Dermanyssus gallinae. At a level of 0.21 mg/cm2, the essential oil from Eucalyptus citriodora achieved 85% mortality in D. gallinae over a 24 h exposure period in contact toxicity tests. A further two essential oils from different eucalyptus species, namely E. globulus and E. radiata, provided significantly (P\0.05) lower mite mortality (11 and 19%, respectively). Notable differences were found between the eucalyptus essential oils regarding their chemical compositions. There appeared to be a trend whereby the essential oils that were composed of the fewer chemical components were the least lethal to D. gallinae. It may therefore be the case that the complexity of an essential oil's chemical make up plays an important role in dictating the toxicity of that oil to pests such as D. gallinae. [ABSTRACT FROM AUTHOR]