Investigation of a gamasid mite infestation in a UK textile mill caused by Dermanyssus gallinae (DeGeer, 1778) (Mesostigmata: Dermanyssidae) special lineage L1

Point mutations in the voltage-gated sodium channel gene conferring pyrethroid resistance in China populations of the Dermanyssus gallinae

BACKGROUND

Dermanyssus gallinae, the poultry red mite (PRM), is a worldwide ectoparasite posing significant economic challenges in poultry farming. The extensive use of pyrethroids for PRM control has led to the emergence of pyrethroid resistance. The objective of this study is to detect the pyrethroid resistance and explore its associated point mutations in the voltage-gated sodium channel (VGSC) gene among PRM populations in China.

RESULTS

Several populations of D. gallinae, namely CJF-1, CJP-2, CJP-3, CSD-4 and CLD-5, displayed varying degrees of resistance to beta-cypermethrin compared to a susceptible field population (CBP-5). Mutations of VGSC gene in populations of PRMs associated with pyrethroid resistance were identified through sequencing its fragments IIS4-IIS5 and IIIS6. The mutations I917V, M918T/L, A924G and L925V were present in multiple populations, while no mutations were found at positions T929, I936, F1534 and F1538.

CONCLUSION

The present study confirmed the presence of extremely high levels of pyrethroid resistance in PRM populations in China, and for the first time detected four pyrethroid resistance mutations in the VGSC gene. Identifying pyrethroid resistance in the field population of PRM in China can be achieved through screening for VGSC gene mutations as an early detection method. Our findings underscore the importance of implementing chemical PRM control strategies based on resistance evidence, while also considering the management of acaricide resistance in the control of PRMs. © 2024 Society of Chemical Industry.

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.

Dermanyssus gallinae in non-avian hosts: A case report in a dog and review of the literature

Non-avian attacks of the worldwide distributed mite Dermanyssus gallinae are occasionally reported. However, it is widely accepted that their occurrence is underestimated. The present study aims to describe the first Italian case of dermanyssosis in a dog, to molecularly characterize the mites collected from the patient and the animal enclosure, where poultry and dog were confined, and to review the current literature on the non-avian attacks by D. gallinae. The dog was successfully treated with an oral sarolaner-based product, followed by a spot-on formulation of imidacloprid and moxidectin. The infestation source was likely attributable to poultry and confirmed by molecular identification of D. gallinae sensu strictu. Ten articles on non-avian D. gallinae attacks in domestic animals and wildlife were retrieved, pointing out the need for more awareness amongst practitioners. The therapeutic effect of available antiparasitic drugs, currently used off-label, should also be better explored in non-avian hosts.

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

Background

Among 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.

Methods

Mite 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.

Results

Mites 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.

Conclusions

Detailed 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.

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.