Ornithonyssus Sylviarum Research Articles

Phylogenetic position of the pigeon mite, Ornithonyssus sylviarum, with amplification of its immunogenetic biomarkers in Egypt

Ornithonyssus sylviarum (O. sylviarum) is an obligatory, blood-sucking ectoparasite widely distributed among poultry and other mammals, causing significant economic losses. This study represented the first report of molecular genotypic identification of O. sylviarum from pigeons, Columba livia domestica, in Egypt. PCR and sequencing of the 28S rRNA gene were conducted. The resulting mite sequences were subjected to BLAST analysis, revealing 90–100% similarity to O. sylviarum in all tested samples. The sequences were deposited in GenBank under the accession numbers PP049086 and PP033720. A phylogenetic tree was constructed to compare the obtained species with related species worldwide. Additionally, infected pigeons showed increased expression of IL-1, IL-10, IFN-γ, and TGF-β3 genes and elevated serum levels of stress biomarkers. The increased level of these cytokines indicates there was a disturbance in the immune status of the infected host with parasite compared with control healthy ones. This increases the susceptibility to infection with other pathogens.

In Vivo Characterization of the Anti-Glutathione S-Transferase Antibody Using an In Vitro Mite Feeding Model.

Poultry red mites (Dermanyssus gallinae, PRMs), tropical fowl mites (Ornithonyssus bursa, TFMs), and northern fowl mites (O. sylviarum, NFMs) are blood-feeding pests that debilitate poultry worldwide. Glutathione S-transferase (GST) plays an important role in the detoxification and drug metabolism of mites. However, research on avian mite GSTs as vaccine antigens is still lacking. Therefore, we aimed to evaluate the potential of avian mite GSTs for vaccine development. We identified GST genes from TFMs and NFMs. We prepared recombinant GST (rGST) from TFMs, NFMs, and PRMs, and assessed their protein functions. Moreover, we evaluated the cross-reactivity and acaricidal effect of immune plasma against each rGST on TFMs, NFMs, and PRMs. The deduced amino acid sequences of GSTs from TFMs and NFMs were 80% similar to those of the PRMs. The rGSTs exhibited catalytic activity in conjugating glutathione to the 1-chloro-2,4-dinitrobenzene substrate. Immune plasma against each rGST showed cross-reactivity with rGST from different mite species. Moreover, the survival rate of PRMs fed with immune plasma against the rGST of TFMs and NFMs was significantly lower than that of the control plasma. These results demonstrate the potential application of GST as an antigen for the development of a broad-spectrum vaccine against avian mites.

Advances in Non-Chemical Tools to Control Poultry Hematophagous Mites.

The blood-sucking mites Dermanyssus gallinae ("red mite"), Ornithonyssus sylviarum ("northern fowl mite"), and Ornithonyssus bursa ("tropical fowl mite") stand out for causing infestations in commercial poultry farms worldwide, resulting in significant economic damage for producers. In addition to changes in production systems that include new concerns for animal welfare, global climate change in recent years has become a major challenge in the spread of ectoparasites around the world. This review includes information regarding the main form of controlling poultry mites through the use of commercially available chemicals. In addition, non-chemical measures against blood-sucking mites were discussed such as extracts and oils from plants and seeds, entomopathogenic fungi, semiochemicals, powder such as diatomaceous earth and silica-based products, and vaccine candidates. The control of poultry mites using chemical methods that are currently used to control or eliminate them are proving to be less effective as mites develop resistance. In contrast, the products based on plant oils and extracts, powders of plant origin, fungi, and new antigens aimed at developing transmission-blocking vaccines against poultry mites provide some encouraging options for the rational control of these ectoparasites.

Acarofauna associated with organic matter in laying aviaries of different rearing systems in Brazil.

Due to the high density of chickens housed within the same space in aviaries, a large volume of organic matter accumulates on the floor. This large supply of available resources allows the development of arthropods, including organisms that affect poultry productivity and health. This study aimed to evaluate the composition of the mite community associated with organic matter in poultry houses with different rearing systems and the verification of potential predators to be evaluated in clean management techniques, such as biological control. The study was carried out in the state of Rio Grande do Sul (Brazil) in a total of six poultry houses, two of the 'Californian' system (SIG) and four of the 'cage free' system (SIF). In total, 839,459 specimens were collected, of which 358,044 were collected from SIF and 481,415 specimens from SIG. Fifty-two species/morphospecies were found and we observed a grouping of aviaries from the same rearing model. Species of medical veterinary importance were found, such as Dermanyssus gallinae, Megninia ginglymura, Ornithonyssus sylviarum and Tyrophagus putrescentiae. The results demonstrate that the organic matter present in the aviaries harbors a high diversity of mites of medical-veterinary importance and predators, which are influenced by the rearing system.

Characterization of cysteine proteases from poultry red mite, tropical fowl mite, and northern fowl mite to assess the feasibility of developing a broadly efficacious vaccine against multiple mite species.

Infestation with poultry red mites (PRM, Dermanyssus gallinae) causes anemia, reduced egg production, and death in serious cases, resulting in significant economic losses to the poultry industry. As a novel strategy for controlling PRMs, vaccine approaches have been focused upon and several candidate vaccine antigens against PRMs have been reported. Tropical (TFM, Ornithonyssus bursa) and northern (NFM, Ornithonyssus sylviarum) fowl mites are also hematophagous and cause poultry industry problems similar to those caused by PRM. Therefore, ideal antigens for anti-PRM vaccines are molecules that cross-react with TFMs and NFMs, producing pesticidal effects similar to those against PRMs. In this study, to investigate the potential feasibility of developing vaccines with broad efficacy across mite species, we identified and characterized cysteine proteases (CPs) of TFMs and NFMs, which were previously reported to be effective vaccine antigens of PRMs. The open reading frames of CPs from TFMs and NFMs had the same sequences, which was 73.0% similar to that of PRMs. Phylogenetic analysis revealed that the CPs of TFMs and NFMs clustered in the same clade as CPs of PRMs. To assess protein functionality, we generated recombinant peptidase domains of CPs (rCP-PDs), revealing all rCP-PDs showed CP-like activities. Importantly, the plasma obtained from chickens immunized with each rCP-PD cross-reacted with rCP-PDs of different mites. Finally, all immune plasma of rCP-PDs reduced the survival rate of PRMs, even when the plasma was collected from chickens immunized with rCP-PDs derived from TFM and NFM. Therefore, CP antigen is a promising, broadly efficacious vaccine candidate against different avian mites.

Study of Laboratory Diagnosis of Colibasilosis Infection In Local Hen In Surabaya

Background: On November 18, 2022, euthanasia and hen necropsy were conducted (protocol number A-164) in the veterinary pathology laboratory, Faculty Of Veterinary Medicine, Wijaya Kusuma University Surabaya. The hen belongs to a local farmer located at Sawahan, Surabaya. Based on the anamnesis, it is known that the hen was four months old and weighed 1.4 kg. The population consists of eight birds, and one of them was sick, never treated or vaccinated, in a cage made of bamboo, corn fodder, rice bran, and drinking water from tap water. Clinical symptoms show a decreased appetite for the last day, watery eyes, runny nose, lethargy, and diarrhea with feces green mixed with white colors. The initial diagnosis of the chicken was infected with Salmonella sp. with a differential diagnosis of Escherichia coli. Purpose: To diagnose bacterial disease in local chickens with a pathological examination, parasitological examination, microbiological isolation, and clinical pathology for hematology. Result: The results of the anatomic pathology examination showed that the chickens had hemorrhagic tracheitis, hemorrhagic necrotic pneumonia, hemorrhagic necrotic enteritis, hemorrhagic necrotic hepatitis, and hemorrhage in the proventriculus. Parasite identification was found in Raillietina sp. and Ornithonyssus sylviarum. Isolation of bacteria was found in Escherichia coli from the duodenum organ. The chickens had hypoproteinemia, poikilocytosis teardrop and rouleaux, leukocytosis with heterophilia, and monocytosis. Conclusion: Based on the examination associated with the results of anamnesis and examination of clinical symptoms, the chickens were diagnosed with Escherichia coli infection together with Raillietina sp. and Ornithonyssus sylviarum infestations.

Potential of ferritin 2 as an antigen for the development of a universal vaccine for avian mites, poultry red mites, tropical fowl mites, and northern fowl mites.

Poultry red mites (PRMs, Dermanyssus gallinae), blood-sucking ectoparasites, are a threat to the poultry industry because of reduced production caused by infestation. In addition, tropical fowl mites (TFMs, Ornithonyssus bursa) and northern fowl mites (NFMs, Ornithonyssus sylviarum) are hematophagous, distributed in various regions, genetically and morphologically close to PRMs, and cause similar problems to the poultry industry. Vaccine approaches have been studied for PRM control, and several molecules have been identified in PRMs as candidates for effective vaccine antigens. The development of an anti-PRM vaccine as a universal vaccine with broad efficacy against avian mites could improve the productivity of poultry farms worldwide. Molecules that are highly conserved among avian mites and have critical functions in the physiology and growth of mites could be ideal antigen candidates for the development of universal vaccines. Ferritin 2 (FER2), an iron-binding protein, is critical for the reproduction and survival of PRMs and has been reported as a useful vaccine antigen for the control of PRMs and a candidate for the universal vaccine antigen in some tick species. Herein, we identified and characterized FER2 in TFMs and NFM. Compared with the sequence of PRM, the ferroxidase centers of the heavy chain subunits were conserved in FER2 of TFMs and NFMs. Phylogenetic analysis revealed that FER2 belongs to clusters of secretory ferritins of mites and other arthropods. Recombinant FER2 (rFER2) proteins from PRMs, TFMs, and NFMs exhibited iron-binding abilities. Immunization with each rFER2 induced strong antibody responses in chickens, and each immune plasma cross-reacted with rFER2 from different mites. Moreover, mortality rates of PRMs fed with immune plasma against rFER2 from TFMs or NFMs, in addition to PRMs, were higher than those of control plasma. rFER2 from each avian mite exhibited anti-PRM effects. This data suggests that it has the potential to be used as an antigen candidate for a universal vaccine against avian mites. Further studies are needed to access the usefulness of FER2 as a universal vaccine for the control of avian mites.

Laying hen production and welfare in a cage-free setting is impacted by the northern fowl mite

The northern fowl mite ( Ornithonyssus sylviarum ) is a common blood-feeding ectoparasite of poultry that can cause decreased egg production and reduced hen welfare. The blood-feeding behavior of the northern fowl mite (NFM) elicits an immune response in hens that leads to decreased egg production, anemia, irritation to flocks and personnel, profit loss, and death to hens in extreme cases. As the egg industry moves toward extensive housing systems, it is important to consider management implications of this switch, such as the impact of NFM infestations. In the present study, hens were infested with NFM in two trials. Production and welfare parameters were monitored throughout the duration of the trials, beginning at 18 weeks of flock age, and ending at 47 and 49 weeks of age for Trials 1 and 2, respectively. A cannibalism issue in Trial 1 resulted in a severe loss of hens by the end of the trial and a low overall NFM infestation, while Trial 2 had consistent NFM infestation levels. In Trial 1, NFM negatively affected hen-day percentage, body weight, and feather coverage of some body regions. In Trial 2, the NFM infestation negatively affected hen-day percentage, mortality, body weight, shell thickness, and feather coverage of some body regions.

Evaluation of the in vitro acaricidal activity of ethanol extracts of seven Chinese medicinal herbs on Ornithonyssus sylviarum (Acari: Macronyssidae)

Ornithonyssus sylviarum (Acari: Macronyssidae) is a common ectoparasite that feeds on the blood of poultry. Following infestation, this mite will cause symptoms such as weight loss, anemia, and decreased egg production. To explore green and safe drugs for the prevention and treatment of O. sylviarum, this study evaluated the effects of ethanol extracts of seven Chinese medicinal herbs—Leonurus artemisia (motherwort), Illicium verum (star anise), Cinnamomum cassia (cinnamon), Hibiscus syriacus, Artemisia argyi (Chinese mugwort), Taraxacum sp. (dandelion), and Syzygium aromaticum (clove)—on O. sylviarum at different life stages. The results showed that different methods of administration affected the acaricidal efficacy of these plant extracts on O. sylviarum. After 6 h of administration with the fumigation method, the acaricidal efficacy of S. aromaticum on adults, nymphs and larvae of O. sylviarum reached 100%. 30 min after administration with the infiltration method, S. aromaticum, H. syriacus and L. artemisia showed acaricidal effects on adults and nymphs of O. sylviarum reaching 100%. In another experiment evaluating the inhibition of egg hatching of O. sylviarum with alcohol extracts of these seven herbs, at 48 h after treatment, A. argyi and C. cassia showed inhibition rates of 19.4%. The results of this study indicate that S. aromaticum induced mortality at all stages of O. sylviarum, whereas A. argyi was found to be the most effective at inhibiting the mite’s egg hatching among the seven herbs. These herbs can therefore be used as potential substitutes for chemical pesticides to prevent and control O. sylviarum. These results provide practical knowledge for the control of O. sylviarum.

Factors associated with prevalence and intensity of the northern fowl mite (Ornithonyssus sylviarum) in commercial poultry farms of Argentina.

The haematophagous mite Ornithonyssus sylviarum may cause important economic losses in commercial poultry farms whilst also potentially affecting the health of farm workers. The dynamics of this ectoparasite has been linked to several factors, including wild birds, fomites, farm workers, management of hen houses, and host traits. Along two consecutive years, we carried out systematic sampling at three laying hen farms located in Santa Fe province, Argentina, with the aim of identifying factors that may influence O. sylviarum prevalence and intensity. We found that the density of feathers around the hen vent area and the presence of Menoponidae lice were negatively associated with mite abundance. We also found that the density of hens in the cages was negatively associated with mite prevalence, suggesting a possible dilution effect, whereas prior reports found a positive association with hen density. In addition, summer was the season with minimum mite prevalences and intensities, contrary to previous studies in northern farms where warm weather appeared to prompt an increase in mite populations. Another factor associated with mite intensity was age, but this effect varied depending on the season, which hints that the association between hen's age and mites is complex. Basic epidemiological knowledge on O. sylviarum in poultry farms from South America may aid in a more efficient and integrative approach to its control.

De novo transcriptome sequencing of the northern fowl mite, Ornithonyssus sylviarum, shed light on parasitiform poultry mites evolution and its chemoreceptor repertoires.

The northern fowl mite (NFM), Ornithonyssus sylviarum, and the poultry red mite (PRM), Dermanyssus gallinae, are the most serious pests of poultry, both of which have an expanding global prevalence. Research on NFM has been constrained by a lack of genomic and transcriptomic data. Here, we report and analyze the first global transcriptome data across all mite live stages and sexes. A total of 28,999 unigenes were assembled, of which 19,750 (68.10%) were annotated using seven functional databases. The biological function of these unigenes was classified using the GO, KOG, and KEGG databases. To gain insight into the chemosensory receptor-based system of parasitiform mites, we furthermore assessed the gene repertoire of gustatory receptors (GRs) and ionotropic receptors (IRs), both of which encode putative ligand-gated ion channel proteins. While these receptors are well characterized in insect model species, our understanding of chemosensory detection in mites and ticks is in its infancy. To address this paucity of data, we identified 9 IR/iGluRs and 2 GRs genes by analyzing transcriptome data in the NFM, while 9 GRs and 41 IR/iGluRs genes were annotated in the PRM genome. Taken together, the transcriptomic and genomic annotation of these two species provide a valuable reference for studies of parasitiform mites and also help to understand how chemosensory gene family expansion/contraction events may have been reshaped by an obligate parasitic lifestyle compared with their free-living closest relatives. Future studies should include additional species to validate this observation and functional characterization of the identified proteins as a step forward in identifying tools for controlling these poultry pests.

Mites and helminths infestation in Lebanese broiler farming systems.

This study aims at the identification of endo- and ectoparasites in broiler farms while assessing their prevalence in semi-open and closed rearing systems in Lebanon. Seventeen semi-open and six closed broiler farms were investigated in various Lebanese provinces between March and September 2020 and 2021. Intestinal and composite litter samples were collected and observed for morphological identification of prevalent parasites. Results notably revealed the prevalence of mites in all of the surveyed farms. Moreover, mixed mite-helminth infestation was recorded in 100% of the semi-open farms and 50% of the closed ones. The northern fowl mite Ornithonyssus sylviarum was the predominant chicken parasitic mite in both systems. The poultry red mite Dermanyssus gallinae, was present in 6% of the semi-open farms and was not detected in closed farms. The mammalian itching mite Sarcoptes scabiei and the grain mite Acarus siro were also identified and had similar prevalence pattern as the red poultry mite. Eggs and/or larvae stages of one parasitic helminth species, Ascaridia galli, were detected in half of the semi-open and closed farms while adult worms were not present. This study documents for the first time the prevalence of specific endo- and ectoparasites in Lebanese broiler farms, reflecting managerial problems and poor biosecurity practices. Nevertheless, the identification of specific parasites in this work paves the way towards implementing proper control methods against these overlooked, yet devastating, organisms.

Urban emergence of Dermanyssus gallinae lineage L1 and Ornithonyssus sylviarum in Hungary: phylogenetic differentiation between the roles of migrating vs transported synanthropic birds

BackgroundAmong Dermanyssoidea, the chicken red mite (Dermanyssus gallinae) and the northern fowl mite (Ornithonyssus sylviarum) are considered to be the cause of high economic losses endured by the poultry industry in the Holarctic region, with O. sylviarum predominating in North America and D. gallinae in Europe. Both species have a short life-cycle (thereby allowing a rapid build-up of massive infestations), a wide range of hosts, synanthropic presence and the ability to bite humans. The aim of this study was to analyze dermanyssoid mite specimens, collected in two human dwellings and two racing pigeon premises in different urban areas in Hungary, with molecular–phylogenetic methods.MethodsMite species were identified morphologically. This was followed by DNA extraction and molecular–phylogenetic analyses of selected mites, based on the cytochrome c oxidase subunit I (cox1) and 28S rRNA (28S) genes.ResultsMites that had invaded a home from a pigeon nest and were linked to human dermatitis were morphologically and molecularly identified as D. gallinae special lineage L1. Specimens collected at all other sampling sites were identified as O. sylviarum, including mites that had invaded a home from a house martin (Delichon urbicum) nest, as well as those which were collected from racing pigeons. House martin- or pigeon-associated O. sylviarum specimens showed the highest sequence identity and closest phylogenetic relationship with conspecific mites reported in GenBank from Israel or Canada, respectively.ConclusionsDetailed morphological and molecular–phylogenetic analyses of D. gallinae lineage L1 confirmed its status as a cryptic species within D. gallinae (s.l.). Taking into account the well-documented latitudinal migratory routes of house martins between Hungary and Africa, O. sylviarum associated with this bird species most likely arrived on its host from the eastern Mediterranean region. On the other hand, mites collected from pigeons in Hungary showed cox1 genetic homogeneity with North American O. sylviarum, which can only be explained by a long-distance (west-to-east intercontinental) connection of birds and their mites as part of human activity (e.g. transportation to exhibitions or trading). In summary, this is the first molecularly confirmed and phylogenetically analyzed case of O. sylviarum infestation of birds in Hungary, implicating urban environment and involving distant parts of the country. This is also the first report of D. gallinae lineage L1 in central Europe.Graphical

ORNITHONYSSUS SYLVIARUM (ACARI: GAMASIDA: MACRONYSSIDAE) A CAUSE OF PRURITIC DERMATITIS FOR POULTRY FARM WORKERS IN SOHAG GOVERNORATE, EGYPT

People urban areas have shared environment with pets and animals, mainly birds and rodents.These animals harbor zoonotic parasites, as mites of the suborder Mesostigmata. The miteswere Dermanyssus gallinae (the poultry red mite) and Ornithonyssus sylviarum & O. bursa,the primary hosts are Rattus norvegicus and Rattus rattus. These species of mites may beharmful to animals, as well as to people working in the shops or potential pet owners. Thestudy dermatological and parasitological evaluated the workers (n=30) in a poultry farming atEl-Kawther, Sohag Governorate for mite pruritus and to identify mites in the period from Julyto October 2019. Detailed history was taken from all workers. Full examination was done.Workers gave history of exposure to insects bite in the poultry farm where they work. Workerswere advised to collect any insects that can bite them or come in contact with their skin,which were referred to Parasitology unit, Sohag University, for identification both by lightmicroscopy and SEM. Examination of all workers revealed that 70% (21/30) of them complainedof itching of variable intensity. Age of participants ranged from 38-41 years all ofthem were males. About pruritus, all cases had insidious onset of pruritus, commonly insummer season (16/21 & 76.19%), especially at night (18/21 & 85.7%), Recurrence of thesymptoms after treatment occurred (11/21 & 52.18%). Patients’ examination showed that skinlesions were more on the exposed sites forming excoriated papules (71.4%) and urticarial lesions(28.6%). Insects collected where examined by using light and SE microscope. Arthropodswere identified as O. sylviarum in all cases.O. sylviarum is a causative agent of human mite dermatitis in Sohag Governorate. The identificationof the cryptic species should be tolerable by amalgamating morphological study withmolecular analyses of mitochondrial DNA sequence.

Common generalist mites do not transmit from foster parents to brood parasitic chicks

AbstractInteractions between avian brood parasites, their hosts and their parasites provide an ideal model system for studying coevolutionary processes across multiple hierarchical levels. Despite this, how brood parasitism affects the ecology and transmission of bird ectoparasites is not well known. Here, we examined the mite fauna of great reed warbler Acrocephalus arundinaceus nests successfully parasitized and unparasitized by the common cuckoo Cuculus canorus to find whether there is vertical transmission of northern fowl mites Ornithonyssus sylviarum, a generalist blood‐feeding parasite of birds, through infected nests. Although there was no difference in the prevalence of mites between successfully parasitized and unparasitized nests, the former nests exhibited two times lower mite abundances than the latter nests. Importantly, none of the common cuckoo nestlings examined shortly before fledging carried mites, whereas the great reed warbler nestlings were infested in almost half of the contaminated nests. Thus, our results indicate that, despite their high dispersal abilities, northern fowl mites may be unable to survive or reproduce on the common cuckoo nestlings. Factors that can contribute to the observed patterns are discussed.

Collecting and Monitoring for Northern Fowl Mite (Acari: Macronyssidae) and Poultry Red Mite (Acari: Dermanyssidae) in Poultry Systems.

The two most economically important poultry ectoparasites are the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the poultry red mite, Dermanyssus gallinae (De Geer). Both mites are obligate blood feeders but differ in where they reside. Sampling methods thus focus on-host, especially the vent feathers, for northern fowl mite and off-host, especially cracks and crevices near the nighttime roosting areas, for poultry red mite. Much remains unknown, however, about the basic biology and ecology of both mites. Here we discuss mite detection, quantification, and decision making and provide thoughts on future directions for research.

An efficient high-welfare feeding device for assessing northern fowl mite interventions in vivo: an improved method for the identification of protective antigens/systemic acaricides/repellent effect

The northern fowl mite (NFM), Ornithonyssus sylviarum, is an obligate hematophagous ectoparasite of domestic and wild birds, and it is an economic pest of laying hen in North America, China, India, Australia, Myanmar, and Brazil. Such an economically important pest remains neglected in many parts of the world, including Asian countries. Therefore, concerted action is required in both basic and applied research directed at the biology and control of this destructive pest. In the present study, we have developed a novel, high-welfare in vivo feeding capsule that would permit pre-screening of new interventions, repellency and deterrence effects of plant-derived products and other semiochemical compounds before proceeding to large-scale field experiments/bioassays, while the minimum number of animals is required to obtain results. Mites were fed on the birds through either a mesh or without a mesh. The average feeding rates of mites was significantly higher when fed directly on chickens, whereas 106 μm nylon mesh was the top-performing mesh when compared with 125 μm aperture nylon mesh. For optimal feeding, the feeding capsules contain NFM and are attached to the skin of the chicken’s thigh for 6 h. This is a simple, reproducible, and easy approach and can be adapted to facilitate many aspects of bioassays.

Mesostigmatid mites (Acari: Mesostigmata) at the domestic-wildlife interface: Poultry and passerine birds of central Argentina

Wild birds may be considered a possible source of parasitic mesostigmatid mites for poultry, but only few studies explored this hypothesis. In addition, there is very little information about the parasitic mites present in commercial poultry systems from southern South America. To contribute with data on parasitic mesostigmatid mites at the domestic-wildlife interface, we conducted a study in which samples were systematically collected from laying hens and wild birds (adults and nestlings), for two years at three commercial laying hen farms. The occurrence of mesostigmatid mites were compared among hosts. A proportion of the collected mites were morphologically identified to the species level, finding that host preference varied greatly depending on mite species: laying hens were only parasitized by Ornithonyssus sylviarum, wild bird nestlings were mostly parasitized by Ornithonyssus bursa, and in small proportion, by O. sylviarum, while adult passerines were parasitized by both Ornithonyssus species, and sporadically by Pellonyssus cf. reedi and Dermanyssus cf. triscutatus. In laying hens, there was intra- and inter-annual variability in mite occurrence, but no consistent seasonal pattern, whereas in adult wild birds, mites showed the highest prevalence in spring and the lowest in summer. Not coinciding with this general pattern, the occurrence of O. bursa matched the reproductive activity of wild birds. A phylogenetic analysis based on a fragment of the 16S rRNA gene was carried out for a subsample of the mites collected, showing that the O. sylviarum mites present on adult wild birds and laying hens had the same haplotype (100% identity). Additionally, mites obtained from wild birds morphologically identified as O. bursa presented two distinctive haplotypes (89.8% identity), one phylogenetically related to O. sylviarum and the other to O. monteiroi. These findings show that in central Argentina commercial laying hens are parasitized mainly by O. sylviarum while wild birds are also hosts to other mite species. Adult wild passerines, especially house sparrows, may be a source of O. sylviarum for commercial poultry.

Parasitic mites alter chicken behaviour and negatively impact animal welfare

The northern fowl mite, Ornithonyssus sylviarum, is one of the most common and damaging ectoparasites of poultry. As an obligate blood feeding mite, the northern fowl mite can cause anaemia, slower growth, and decreased egg production of parasitized birds. However, the impact of mites or other ectoparasites on hen behaviour or welfare is not well studied. Here, we use activity sensors (three-axis accelerometers) affixed to individual birds to continuously record hen movement before, during, and after infestation with mites. Movements recorded by sensors were identified to specific bird behaviours through a previously trained algorithm, with frequency of these behaviours recorded for individual birds. Hen welfare was also determined before, during, and after mite infestation of hens using animal-based welfare metrics. Northern fowl mites significantly increased hen preening behaviour and resulted in increased skin lesions of infested birds.

DETERMINATION OF THE PRESENCE OF Ornithonussus spp. IN BREEDER HENS AND ROOSTERS IN THREE GENETIC LINES ON A FARM IN SOLANO COUNTY, CALIFORNIA, USA

Acarosis in birds may cause irritation, stress, reduction of food intake and, consequently, reduction in egg production and quality. In this sense, the Ornithonyssus sylviarum mite is considered one of the most aggressive mites to bird health due to its permanent behavior. The objective of this work is to determine the presence of Ornithonyssus spp. in three genetic lines of pedigree breeding chickens and roosters on a farm in the state of California, USA, and identify the species of Ornithonyssus spp. present in the three genetic lines studied. A sampling of 103 pedigree chickens and roosters was carried out to determine the presence of Ornithonyssus spp. The samples were collected from the feathers under the cloaca, preserved in 70% alcohol, then rinsed with 10% sodium hydroxide and evaluated, by direct observation through the microscope and stereoscope, in order to visualize and identify their morphological characteristics. The results show the presence of Ornithonyssus spp. in 99.0% (102/103) of the birds, identifying an average of 135, 121 and 30 mites per bird according to lines A, B and C, respectively. The species identified were Ornithonyssus sylviarum, Ornithonyssus bursa and Ornithonyssus bacoti in 89.8%, 1.4% and 0.8% respectively, with 8.1% Ornithonyssus spp. In conclusion, Ornithonyssus spp. was present in the pedigree breeding chickens and roosters in the three genetic lines. Ornithonyssus sylviarum was the predominant species.