Phylogenetic Inference Using Cytochrome C Oxidase Subunit I (COI) in the Poultry Red Mite, Dermanyssus gallinae in the United Kingdom Relative to a European Framework

One health approach to study human health risks associated with Dermanyssus gallinae mites

Despite the significant health risks associated with Dermanyssus gallinae infestations in humans, they are often overlooked. This study investigated a household case of D. gallinae infestation and explored the resulting clinical manifestations and risk of infection in family members. Microfluidic PCR was employed for high-throughput screening of pathogens in collected mites and blood samples from both chickens and family members. Morphological and molecular examinations confirmed the identity of the mites as D. gallinae sensu stricto (s.s.), with evidence indicating recent blood feeding. Results indicated that the mites exclusively harbored various pathogens, including Bartonella spp., Ehrlichia spp., Apicomplexa, and Theileria spp. Blood samples from family members and poultry tested negative for these pathogens, suggesting a potential reservoir role for D. gallinae. The study further identified haplotypes of D. gallinae, classifying them into D. gallinae s.s., cosmopolitan haplogroup A. Serological analysis revealed elevated IgE seroreactivity against mite proteins in the family member with bite lesions. Antibodies against Bartonella spp. were detected in this individual, indicating exposure to the pathogen. In summary, this study sheds light on the clinical manifestations, pathogen detection, and genetic characterization of D. gallinae infestations, underscoring the necessity of adopting comprehensive approaches to manage such infestations effectively.

Genetic Characterization of the Poultry Red Mite (Dermanyssus gallinae) in Poland and a Comparison with European and Asian Isolates

(1) Background: The blood-feeding mite Dermanyssus gallinae (De Geer 1778) continues to attract wide interest from researchers and bird breeders. The aim of this study was to evaluate the genetic diversity of D. gallinae populations in five commercial laying hen farms in Poland and to determine their similarity with isolates from other countries. The study involved an analysis of a fragment of the cytochrome c oxidase subunit I gene (COI). A total of 38 isolates obtained from Polish farms and 338 sequences deposited in GenBank were analyzed. (2) Results: Haplotype No. 46 was dominant (90%) in Polish isolates and was homologous with the isolates from Great Britain, the Netherlands, Belgium, Japan, and South Korea. These results are indicative of high genetic homogeneity and common ancestry of the poultry red mite and point to a common source of infestation in the examined farms. (3) Conclusions: The genetic diversity of D. gallinae should be further studied to promote a better understanding of how this parasite is disseminated within and between countries.

Population genetic structure of Neoschongastia gallinarum in South China based on mitochondrial DNA markers

The genetic diversity and differentiation of four geographic populations of Neoschongastia gallinarum were evaluated using concatenated mitochondrial gene sequences (pCOI, pCOII, and pND5). Based on the results, the N. gallinarum populations had high genetic diversity and strong ecological adaptability. Genetic differentiation among paired populations calculated using concatenated mitochondrial gene sequences revealed that geographic isolation resulted in genetic differentiation among the populations of N. gallinarum, and gene flow between populations associated with human trade activities. Systematic development and molecular variance based on haplotypes revealed that genetic variation existed in different haplotypes; however, no clear rule related to geographic region was found. Further, genetic variation was mainly derived from individuals within the population. A neutral test based on concatenated mitochondrial gene sequences and nucleotide pair differences revealed that N. gallinarum did not experience an obvious population expansion in recent historical periods. Accordingly, the population size was relatively stable.

Phylogenetic Diversity of Dermanyssus gallinae (Dermanyssidae) based on Mitochondrial Cytochrome Oxidase-1 Gene Sequence Collected from Different Bird Species in Iran

A wide range of hosts, especially birds, can be infested with Dermanyssus gallinae (D. gallinae), as an obligate hematophagous mite. In this study, cytochrome oxidase 1 (CO1) gene sequences were employed to perform molecular and phylogenetic analyses of D. gallinae collected from different bird species in Iran. Adult mites were collected from the body surface and cage material of ornamental and wild birds in industrial farms located in the Western and Northwestern regions of Iran. The infestation was identified in layer poultry farming by inspecting the eggs and the whole surfaces of the birds' bodies. The holding area and body surface of the ornamental and wild birds were also thoroughly examined. The D. gallinae samples were assigned to two subgroups of haplogroup A (i.e., A1 and A2). The phylogenetic tree suggested that the D. gallinae samples collected from wild birds in the A1 sub-haplogroup should be placed beside Japanese, Norwegian, Italian, and French samples isolated from wild birds in the A2 sub-haplogroup. Additionally, the highest phylogenetic similarity in the A2 sub-group was observed between mites isolated from ornamental and industrial birds in Australia. The findings of the present study suggest that crows and sparrows may play an important role in the transmission of D. gallinae infestation to other species of wild birds due to their high population, as well as their presence in most areas.

Biochemical and molecular mechanisms of acaricide resistance in Dermanyssus gallinae populations from Turkey

The poultry red mite, Dermanyssus gallinae, is the most important blood sucking ectoparasite of egg laying hens and causes economic losses in poultry farms worldwide. Although various management methods exist, the control of poultry red mites (PRMs) mainly relies on acaricides such as pyrethroids and organophosphates (OPs) in many regions of the world. However, repeated use of these synthetic chemicals has resulted in resistance development causing control failure of PRM. In this study, we investigated acaricide resistance mechanisms of Turkish PRM populations. First, we obtained the COI sequence from 30 PRM populations from different regions in Turkey and identified four different COI haplotypes. Toxicity assays showed that four field-collected PRM populations were highly resistant to the pyrethroid alpha-cypermethrin, with resistance ratios (RRs) varying between 100- and 400-fold, while two of these populations had a RR of more than 24-fold against the OP acaricide phoxim. Biochemical assays showed a relatively higher activity of glutathione-S-transferases and carboxyl-cholinesterases, two well-known classes of detoxification enzymes, in one of these resistant populations. In addition, we also screened for mutations in the gene encoding the voltage-gated sodium channel (vgsc) and acetylcholinesterase 1 (ace-1), the target-site of pyrethroids and OPs, respectively. In all but two PRM populations, at least one vgsc mutation was detected. A total of four target-site mutations, previously associated with pyrethroid resistance, M918T, T929I, F1534L, F1538L were found in domain II and III of the VGSC. The T929I mutation was present in the vgsc of almost all PRM populations, while the other mutations were only found at low frequency. The G119S/A mutation in ace-1, previously associated with OP resistance, was found in PRM for the first time and present in fourteen populations. Last, both alive and dead PRMs were genotyped after pesticide exposure and supported the possible role of target-site mutations, T929I and G119S, in alpha-cypermethrin and phoxim resistance, respectively. To conclude, our study provides a current overview of resistance levels and resistance mutations in Turkish PRM populations and might aid in the design of an effective resistance management program of PRM in Turkey.

A Rickettsiella Endosymbiont Is a Potential Source of Essential B-Vitamins for the Poultry Red Mite, Dermanyssus gallinae

Many obligate blood-sucking arthropods rely on symbiotic bacteria to provision essential B vitamins that are either missing or at sub-optimal levels in their nutritionally challenging blood diet. The poultry red mite Dermanyssus gallinae, an obligate blood-feeding ectoparasite, is a serious threat to the hen egg industry. Poultry red mite infestation has a major impact on hen health and welfare and causes a significant reduction in both egg quality and production. Thus far, the identity and biological role of nutrient provisioning bacterial mutualists from D. gallinae are little understood. Here, we demonstrate that an obligate intracellular bacterium of the Rickettsiella genus is detected in D. gallinae mites collected from 63 sites (from 15 countries) across Europe. In addition, we report the genome sequence of Rickettsiella from D. gallinae (Rickettsiella - D. gallinae endosymbiont; Rickettsiella DGE). Rickettsiella DGE has a circular 1.89Mbp genome that encodes 1,973 proteins. Phylogenetic analysis confirms the placement of Rickettsiella DGE within the Rickettsiella genus, related to a facultative endosymbiont from the pea aphid and Coxiella-like endosymbionts (CLEs) from blood feeding ticks. Analysis of the Rickettsiella DGE genome reveals that many protein-coding sequences are either pseudogenized or lost, but Rickettsiella DGE has retained several B vitamin biosynthesis pathways, suggesting the importance of these pathways in evolution of a nutritional symbiosis with D. gallinae. In silico metabolic pathway reconstruction revealed that Rickettsiella DGE is unable to synthesize protein amino acids and, therefore, amino acids are potentially provisioned by the host. In contrast, Rickettsiella DGE retains biosynthetic pathways for B vitamins: thiamine (vitamin B1) via the salvage pathway; riboflavin (vitamin B2) and pyridoxine (vitamin B6) and the cofactors: flavin adenine dinucleotide (FAD) and coenzyme A (CoA) that likely provision these nutrients to the host.

Who Is Dermanyssus gallinae? Genetic Structure of Populations and Critical Synthesis of the Current Knowledge

Despite the economic and animal welfare importance of the Poultry Red Mite Dermanyssus gallinae, its genetic structure has been studied in a scattered way so far. The prophylaxis and control of such a globally distributed ectoparasite can be significantly improved by understanding its genetic population structure (composition in species and intraspecific variants). The present study aims to establish a rigorous framework for characterizing the neutral genetic structure of D. gallinae based on a literature review combined with an integrative analysis of the data available in GenBank on population-level nucleotide sequence diversity supplemented by a new dataset. The integrative analysis was conducted on sequence data extracted from GenBank coupled with new sequences of two fragments of the mitochondrial gene encoding Cytochrome Oxidase I (CO1) as well as of an intron of the nuclear gene encoding Tropomyosin (Tpm) from several PRM populations sampled from European poultry farms. Emphasis was placed on using the mitochondrial gene encoding CO1 on which the main universal region of DNA barcoding in animals is located. The species D. gallinae sensu lato is a species complex, encompassing at least two cryptic species, i.e., not distinguishable by morphological characters: D. gallinae sensu stricto and D. gallinae L1. Only D. gallinae s.s. has been recorded among the populations sampled in poultry farms worldwide. Current knowledge suggests they are structured in three mitochondrial groups (haplogroups A, B, and C). Haplogroup A is cosmopolitan, and the other two present slightly contrasted distributions (B rather in the northern part of Europe, C most frequently found in the southern part). Recent data indicate that a dynamic geographic expansion of haplogroup C is underway in Europe. Our results also show that NUMT (nuclear mitochondrial DNA) pseudogenes have generated artifactual groups (haplogroups E and F). It is important to exclude these artifact groups from future analyses to avoid confusion. We provide an operational framework that will promote consistency in the analysis of subsequent results using the CO1 fragment and recommendations for future analyses.

Case of Human Infestation with Dermanyssus gallinae (Poultry Red Mite) from Swallows (Hirundinidae)

Dermanyssus gallinae (the poultry red mite, PRM) is an important ectoparasite in the laying hen industry. PRM can also infest humans, causing gamasoidosis, which is manifested as skin lesions characterized by rash and itching. Recently, there has been an increase in the reported number of human infestation cases with D. gallinae, mostly associated with the proliferation of pigeons in cities where they build their nests. The human form of the disease has not been linked to swallows (Hirundinidae) before. In this report, we describe an incident of human gamasoidosis linked to a nest of swallows built on the window ledge of an apartment in the island of Kefalonia, Greece. Mites were identified as D. gallinae using morphological keys and amplifying the Cytochrome C oxidase subunit I (COI) gene by PCR. Bayesian phylogenetic analysis and median-joining network supported the identification of three PRM haplogroups and the haplotype isolated from swallows was identical to three PRM sequences isolated from hens in Portugal. The patient was treated with topical corticosteroids, while the house was sprayed with deltamethrin. After one week, the mites disappeared and clinical symptoms subsided. The current study is the first report of human gamasoidosis from PRM found in swallows’ nest.