Poultry Red Mite Dermanyssus Gallinae Research Articles

Characterization of Erysipelothrix rhusiopathiae isolates from laying hens and poultry red mites (Dermanyssus gallinae) from an outbreak of erysipelas

Infection with the zoonotic bacterium Erysipelothrix rhusiopathiae causes severe disease outbreaks (erysipelas) in poultry flocks. As this bacterium has been isolated from the poultry red mite (Dermanyssus gallinae), this parasite has been suggested as a possible means of transmission of E. rhusiopathiae on and between poultry farms. To further elucidate the capacity of the mite as a reservoir, we analysed and compared 56 bacterial isolates from laying hens and nine isolates from mites by pulsed-field gel electrophoresis (PFGE), using the restriction enzyme SmaI. The isolates originated from one outbreak in a laying hen flock housed in an indoor litter-based aviary system. Except for two isolates, a homogeneous banding pattern was obtained from all isolates analysed, suggesting that a single strain was the cause of the outbreak. Another finding was that isolates from individual hens could exhibit slightly different PFGE patterns. Mites collected from the same house at the end of the production period of the following flock were negative for the presence of E. rhusiopathiae. An increasing number of erysipelas outbreaks as well as escalating problems with D. gallinae are expected in other European countries related to the forthcoming changes in housing systems for laying hens. Consequently, further studies are needed to investigate the importance of erysipelas in poultry and the importance of D. gallinae in the transmission of E. rhusiopathiae.

Modelling population dynamics and response to management options in the poultry red mite Dermanyssus gallinae (Acari: Dermanyssidae)

The poultry red mite Dermanyssus gallinae is a major pest and widespread ectoparasite of laying hens and other domestic and wild birds. Under optimal conditions, D. gallinae can complete its lifecycle in less than 10 days, leading to rapid proliferation of populations in poultry systems. This paper focuses on developing a theoretical model framework to describe the population dynamics of D. gallinae. This model is then used to test the efficacy and residual effect of different control options for managing D. gallinae. As well as allowing comparison between treatment options, the model also allows comparison of treatment efficacies to different D. gallinae life stages. Three different means for controlling D. gallinae populations were subjected to the model using computer simulations: mechanical cleaning (killing once at a given time all accessible population stages), sanitary clearance (starving the mite population for a given duration, e.g. between flocks) and acaricide treatment (killing a proportion of nymphs and adults during the persistence of the treatment). Simulations showed that mechanical cleaning and sanitary clearance alone could not eradicate the model D. gallinae population, although these methods did delay population establishment. In contrast, the complete eradication of the model D. gallinae population was achieved by several successive acaricide treatments in close succession, even when a relatively low treatment level was used.

In vitro and field studies on the contact and fumigant toxicity of a neem-product (Mite-Stop®) against the developmental stages of the poultry red mite Dermanyssus gallinae

The acaricidal activity of the neem product MiteStop was investigated for its potential use as a botanical acaricide for the control of the poultry red mite Dermanyssus gallinae. This neem product is a special formulation of an extract of the seeds of the neem tree Azadirachta indica A. Juss. The efficacy was tested under laboratory conditions as well as in poultry houses. Four different methods of application were used in a filter paper bioassay to evaluate contact and vapour phase toxicity tests. The neem product proved to be already active in very small doses. In order to investigate the efficacy under field conditions, a poultry house was sprayed twice within a 7-day period using 1:33 and 1:50 diluted MiteStop. Cardboard traps were used to assess the mite population before, during and after the treatment. The mite population could be reduced by 89%. In a second poultry house, the spraying of defined areas with a 1:30, 1:33 or 1:50 dilution of the acaricide proved to be highly efficacious against all mite stages. Three other field trials proved that MiteStop is highly active against the red poultry mite. The most efficient dilution is 1:33 with tap water and spraying two or three times at intervals of 7 days.

Online Reproducible Research: An Application to Multivariate Analysis of Bacterial DNA Fingerprint Data

This paper presents an example of online reproducible multivariate data analysis. This example is based on a web page providing an online computing facility on a server. HTML forms contain editable R code snippets that can be executed in any web browser thanks to the Rweb software. The example is based on the multivariate analysis of DNA fingerprints of the internal bacterial flora of the poultry red mite Dermanyssus gallinae. Several multivariate data analysis methods from the ade4 package are used to compare the fingerprints of mite pools coming from various poultry farms. All the computations and graphical displays can be redone interactively and further explored online, using only a web browser. Statistical methods are detailed in the duality diagram framework, and a discussion about online reproducibility is initiated.

A pilot study into the chemical and sensorial effect of thyme and pennyroyal essential oil on hens eggs

SummaryPreviously, it has been shown that thyme and pennyroyal essential oils have potential as acaricides against the poultry red mite Dermanyssus gallinae. The effect of these oils on the occurrence of taint in hens’ eggs was investigated using in vitro immersion tests and in vivo methods where poultry huts containing laying hens were sprayed weekly with oil. Analysis of extracts from eggs by gas chromatography mass spectrometry (GCMS) showed that no detectable taint was present in hens’ eggs. However, consumer sniff tests, although restricted and only preliminary in nature, showed a significant negative response to the smell of both unbroken and cracked open eggs between those taken from poultry huts treated with pennyroyal essential oil and all other eggs tested. Some essential oils, such as thyme, may be more suitable as an acaracidal product than others, such as pennyroyal, for the use within a commercial poultry system for laying hens.

In vitro efficacies of oils, silicas and plant preparations against the poultry red mite Dermanyssus gallinae

The aim of this study was to test the effectiveness of physically acting substances (oils and silicas) and plant preparations for the control of the poultry red mite Dermanyssus gallinae (De Geer 1778). Reproduction and survival of fed D. gallinae females were evaluated in vitro for a total of 168 h using the "area under the survival curve" (AUC) to compare survival of the mites between treatments. Four oils (two plant oils, one petroleum spray oil and diesel), one soap, three silicas (one synthetic amorphous silica, one diatomaceous earth (DE) and one DE with 2% pyrethrum extract) and seven plant preparations (derived from Chrysanthemum cineariaefolium, Allium sativum, Tanacetum vulgare, Yucca schidigera, Quillaja saponaria, Dryopteris filix-mas, and Thuja occidentalis) were tested at various concentrations. All the oils, diesel and soap significantly reduced D. gallinae survival. All silicas tested inhibited reproduction. DE significantly reduced mite survival, but amorphous silica was less effective in vitro. Except for pure A. sativum juice and the highest concentration of C. cineariaefolium extract, the plant preparations tested resulted in statistically insignificant control of D. gallinae.

Exploration of the susceptibility of AChE from the poultry red mite Dermanyssus gallinae (Acari: Mesostigmata) to organophosphates in field isolates from France

The red fowl mite Dermanyssus gallinae (De Geer, 1778) is a hematophagous mite species, which is very commonly found in layer facilities in Europe. The economic and animal health impact of this parasite is quite important. In laying hen houses, organophosphates are almost the only legally usable chemicals. Detecting a target resistance can be useful in order to limit the emergence of resistant populations. The acetylcholinesterase (AChE) activity and the enzyme sensitivity to paraoxon was investigated in 39 field samples and compared to a susceptible reference strain (SSK). Insensitivity factor values (expressed as IC50 ratio) obtained from field isolates compared to SSK revealed some polymorphism but not exceeding a 6-fold difference. The kinetic characteristics of AChE from some field samples showed some difference in KM values for acetylthiocholine and inhibition kinetics performed with diethyl paraoxon exhibited a 5.5-fold difference in the bimolecular rate constant in one field isolate. Taken together, these data suggested that differences in AChE susceptibility to organophosphates may exist in D. gallinae but no resistant population was found.

Repellence of plant essential oils to Dermanyssus gallinae and toxicity to the non-target invertebrate Tenebrio molitor

With changes in legislation and consumer demand, alternatives to synthetic acaricides to manage the poultry red mite Dermanyssus gallinae (De Geer) in laying hen flocks are increasingly needed. These mites may cause losses in egg production, anaemia and even death of hens. It may be possible to use plant-derived products as D. gallinae repellents, especially if such products have a minimal impact on non-target organisms. An experiment was conducted with D. gallinae to assess the repellence of a range of plant essential oils, previously found to be of varying toxicity (relatively highly toxic to non-toxic) to this pest. Experiments were also undertaken to assess the toxicity of these products to mealworm beetles ( Tenebrio molitor L.), a non-target invertebrate typical of poultry production systems. Results showed that all seven essential oils tested (manuka, thyme, palmarosa, caraway, spearmint, black pepper and juniper leaf) were repellent to D. gallinae at 0.14 mg oil/cm 3 (initial concentration) during the first 2 days of study. Thyme essential oil appeared to be the most effective, where repellence lasted until the end of the study period (13 days). At the same concentration toxicity to T. molitor differed, with essential oils of palmarosa and manuka being no more toxic to adult beetles than the control. There was neither a significant association between the rank toxicity and repellence of oils to D. gallinae, nor the toxicity of oils to D. gallinae (as previously determined) and T. molitor.

Characterization of Erysipelothrix rhusiopathiae isolates from poultry, pigs, emus, the poultry red mite and other animals

Erysipelothrix rhusiopathiae is the causative agent of erysipelas in mammals and birds, especially pigs and poultry. In order to investigate the suitability of different subtyping methods for genetic and phenotypic similarities among Swedish isolates of the organism, 45 isolates from poultry ( n = 23), pigs ( n = 17), emus ( n = 2) and the poultry red mite Dermanyssus gallinae ( n = 3) were investigated by serotyping, pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing. Sequence analysis of the 16S rRNA gene was performed on eleven isolates from nine animal species. The results indicated a random scattering of serotypes throughout the dendrogram based on PFGE banding patterns following SmaI digestion. In three cases, isolates with an identical PFGE pattern were of differing serotypes. No differentiation into subgroups by antimicrobial susceptibility testing by broth microdilution was possible as results were similar for all isolates. The Minimum Inhibitory Concentrations for most antimicrobials, including penicillin and oxytetracycline, were low. The 16S rRNA gene sequences (1443 nts) from eight of eleven selected isolates of Erysipelothrix spp. were identical to that of the type strain E. rhusiopathiae ATCC 19414 T. The other three isolates differed from the type strain by two or three nucleotides. While this method may be useful for identification of Erysipelothrix spp., it is unsuitable for epidemiological investigations. Similarities in PFGE banding patterns between isolates from chickens and mites supported the hypothesis that D. gallinae may act as a reservoir and vector for E. rhusiopathiae. Further PFGE studies on E. rhusiopathiae isolates are appropriate to investigate the epidemiology of poultry erysipelas.

The Poultry Red Mite Dermanyssus gallinae as a Potential Carrier of Vector‐borne Diseases

The poultry red mite Dermanyssus gallinae is an obligatory blood-sucking parasite that is considered to be one of the most important ectoparasites in the poultry industry, mainly because it is responsible for important economic losses, leads to a reduction of welfare of laying hens, and may pose a disease risk to humans. As a result of these problems, much of the current research on this parasite targets new methods of control. Less attention has been paid to the importance of D. gallinae as a carrier of vector-borne diseases. Some authors have mentioned the possible involvement of D. gallinae in the transmission (both in vitro and directly isolated from the mites) of viral and bacterial agents. Our research group has demonstrated the presence of Mycobacterium spp. within D. gallinae. DNA coding for Mycobacterium spp. was successfully amplified from unfed adult D. gallinae, larvae, and eggs by using reverse transcription-polymerase chain reaction targeting the 16S rRNA gene. The results have suggested the possible transovarial and transstadial transmission of pathogens by D. gallinae.

Histamine Release Factor from Dermanyssus gallinae (De Geer): Characterization and in vitro assessment as a protective antigen

A cDNA encoding a 174-amino-acid orthologue of a tick histamine release factor (HRF) was identified from the haematophagous poultry red mite Dermanyssus gallinae. The predicted D. gallinae HRF protein ( Dg-HRF-1) sequence is highly conserved with the tick HRFs (identity 52–54%) and to a lesser degree with translationally controlled tumour proteins (TCTP) from mammals and other invertebrates (range 38–47%). Phylogenetically, Dg-HRF-1 partitions with the tick HRF clade suggesting a shared linage and potentially similar function(s). A recombinant Dg-HRF-1 protein (r Dg-HRF-1) was produced and shown to induce degranulation of rat peritoneal mast cells in vitro, confirming conservation of the histamine-releasing function in D. gallinae. Polyclonal antibodies were generated in rabbits and hens to r Dg-HRF-1. Western blotting demonstrated that native Dg-HRF is a soluble protein and immunohistochemical staining of mite sections revealed that the distribution of Dg-HRF, although ubiquitous, is more common in mite reproductive, digestive and synganglion tissues. A survey of hens housed continuously in a mite-infested commercial poultry unit failed to identify IgY specific for recombinant or native Dg-HRF, indicating that Dg-HRF is not exposed to the host during infestation/feeding and may therefore have potential as a vaccine using the concealed antigen approach. To test the protective capability of r Dg-HRF-1, fresh heparinised chicken blood was enriched with yolk-derived anti- Dg-HRF IgY antibodies and fed to semi-starved mites using an in vitro feeding system. A statistically significant increase in mortality was shown ( P = 0.004) in mites fed with anti- Dg-HRF IgY after just one blood meal. The work presented here demonstrates, to our knowledge for the first time, the feasibility of vaccinating hens with recombinant D. gallinae antigens to control mite infestation and the potential of r Dg-HRF-1 as a vaccine antigen.

Field study on the efficacy of an extract of neem seed (Mite -Stop®) against the red mite Dermanyssus gallinae naturally infecting poultry in Egypt

Infestations with the poultry red mite Dermanyssus gallinae represent a major ectoparasite problem in poultry and affects egg and meat production worldwide. The effects of the neem seed product Mite-Stop against the red poultry mite were investigated. Five primitive poultry farms in two small villages in the Nile Delta and Giza district were selected for the study. The neem extract was diluted 1:40 and 1:50 with tap water just prior to use. Application of the two dilutions of the provided product was performed to soil, cracks and crevices of the examined area as well as to mite-infested birds on day 0 and day 7. Two hours after treatment soil dust was collected from sprayed regions of the stable and from unsprayed control regions of the same stable. The treated chickens were also checked for mites 2 h after each treatment. The examination of the chickens 2 h after spraying showed that they were free of mites. The examination of treated soil with the Tullgren funnel apparatus 2 h after the first spraying on day 0 already showed a considerable reduction of living mites compared to controls. Seven days after the first treatment of the soil the number of living mites was reduced for 80% in the treated soil and decreased even more after the second spraying, since those larvae that had hatched from eggs in the meantime were killed. The 1:40 dilution of the neem seed extract with tap water was superior to the 1:50 dilution. These results clearly show a very high killing rate of the extract, if the mites come in direct contact with the compound. However, in order to obtain extinction also of hidden and freshly hatched stages repeated spraying should be done three times within 8-10 days.

Field efficacy of phoxim 50% (ByeMite®) against the poultry red mite Dermanyssus gallinae in battery cages stocked with laying hens

Infestations with the poultry red mite Dermanyssus gallinae represent a major ectoparasite problem in poultry and can affect egg layers worldwide. There is presently a lack of an ectoparasiticide in Europe for poultry which can assure a 0-day withholding period for eggs. In this study, ByeMite® (phoxim 50%, Bayer HealthCare, Animal Health Division) was administered to treat a D. gallinae infestation in a poultry house stocked with egg-laying hens kept in a cage system. A layer house was sprayed twice within a 7-day interval using a solution containing 2000ppm phoxim and a similar layer house was used as an untreated control unit. Specially developed D. gallinae traps made of cardboard were used to assess the mite density in both layer houses during a 49-day period after the treatment. In order to collect mites, the traps were placed on days −1, 2, 6, 9, 13, 20, 34 and 48 and always removed after 24h. The collected mites were counted and differentiated according to their developmental stage (mite eggs, larvae, nymphs, adults). Three days after the first spray treatment, the efficacy against all mite stages (larvae, nymphs, adults) was 96.1%, and from day 7 post-treatment until the end of the trial (day 49) the efficacy exceeded 99%. In contrast, in the untreated layer house (negative control group) the mite population showed a 400% increase. No treatment-related side effects in chickens were detectable. It is concluded that two administrations of ByeMite® within a 7-day interval are highly effective against D. gallinae infestations in a stocked poultry house.

Assessment of susceptibility of the poultry red mite Dermanyssus gallinae (Acari: Dermanyssidae) to some acaricides using an adapted filter paper based bioassay

A previously described bioassay was modified to assess the response of the poultry red mite, an important ectoparasite of fowl, to a selected group of acaricides. The adapted bioassay is simple to use, escape-proof and provides data that can be subjected to probit analysis. The reproducibility of the method was assessed by three tests with α-cypermethrin against a reference strain, which produced dose-response lines that did not differ significantly ( χ 2 = 1.39, 2 d.f., p = 0.50), and had a derived common slope of 1.89. In addition, a limited evaluation study enabled assessment of response to commercial formulations of bifenthrin, bifenthrin + malathion and cypermethrin by field populations of the poultry red mite.

Determination of phoxim residues in eggs by using high-performance liquid chromatography diode array detection after treatment of stocked housing facilities for the poultry red mite (Dermanyssus gallinae)

The poultry red mite Dermanyssus gallinae is the most important ectoparasite of poultry in several European countries. Phoxim is a well-known antiparasitic agent in wide use. Initial studies indicated that this compound could successfully be applied to eliminate D. gallinae in egg-laying birds and in henhouses by treating the cages and the equipment with it. In order to investigate whether phoxim residues are present in eggs from laying hens, we developed a selective and sensitive high-performance liquid chromatography method employing a simple water/acetonitrile gradient system. The amount of phoxim was determined by UV detection at 281nm, and the presence of the residue was confirmed by diode array detection. The eggs were homogenized for sample pretreatment and extracted with acetonitrile and partitioned with n-hexane. The acetonitrile extract was further purified with silica gel column chromatography. Recovery rates (performed at the 5–120μgkg−1 level) were in the range of 86.0–92.1% with relative standard deviations between 3.1% and 16.3%. Based on a signal to noise ratio of 3, the limit of detection of the assay was approximately 2μgkg−1. The day-to-day variation in the concentration of phoxim in four contaminated eggs (5.7–51.6μgkg−1) was generally less than 20%. The decision limit (CCα) and the detection capability (CCβ) were 62.0 and 68.7μgkg−1, respectively. The applicability of the method was demonstrated in eggs from three clinical trials and from a field study. In these investigations, all animals were kept in conventional battery cages. No sample was found containing more than the maximum residue level of 60μgkg−1 for phoxim in eggs as given in Annex I of Council Regulation (EEC) No. 2377/90.