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

The poultry red mite (PRM), Dermanyssus gallinae (De Geer), and the northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago), 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 transcriptome data for this species. 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 predicted 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 helps 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.

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.

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.

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.

Ornithonyssus sylviarum (Acari: Macronyssidae) parasitism among poultry farm workers in Minas Gerais state, Brazil

ABSTRACT: Ornithonyssus sylviarum is a hematophagous mite present in wild, domestic, and synanthropic birds. However, this mite can affect several vertebrate hosts, including humans, leading to dermatitis, pruritus, allergic reactions, and papular skin lesions. This study evaluated the epidemiological characteristics of O. sylviarum attacks on poultry workers, including data on laying hens, infrastructure and management of hen houses, and reports of attacks by hematophagous mites. In addition, a case of mite attack on a farm worker on a laying farm in the Midwest region in Minas Gerais is presented. It was found that 60.7% farm workers reported attacks by hematophagous mites. Correspondence analysis showed an association between reports of mite attacks in humans with (1) presence of O. sylviarum in the hen house, (2) manual removal of manure by employees, and (3) history of acaricide use. The specimens collected from the location were confirmatively identified as O. sylviarum. O. sylviarum attacks ave not been reported when manure was removed in a shorter time interval and did not use acaricide in the sheds when the removal was done by manure conveyor belt. Parasitism by O. sylviarum should be considered a relevant occupational hazard affecting employees working in direct contact with commercial egg-laying hens in Minas Gerais. We emphasized the need to monitor hen infestations by this mite to improve the development of mite control strategies.

Molecular characterization and genetic diversity of Ornithonyssus sylviarum in chickens (Gallus gallus) from Hainan Island, China

Background The northern fowl mite (NFM), Ornithonyssus sylviarum, is an obligatory hematophagous ectoparasite of birds and one of the most important pests in the poultry industry on several continents. Although NFM poses a serious problem, it remains a neglected pest of poultry in China and other Asian countries. Therefore, a molecular analysis was conducted to provide baseline information on the occurrence, genetic diversity and emergence of NFM in poultry farms from China. Methods This study focused on morphological description and identification of adults based on electron microscopy, molecular sequencing of the mitochondrial cox1 gene and phylogenetic analysis. We have also used the DNA sequences of the cox1 gene to study the genetic diversity, population structure and demographic history. The neutrality tests were used to analyze signatures of historical demographic events. Results The mites collected were identified as the northern fowl mite Ornithonyssus sylviarum based on external morphological characterization using electron microscopy. Molecular analysis using a 756-bp long partial fragment of the cox1 gene revealed 99–100% sequence identity with NFM and phylogenetic inferences showed a bootstrap value of 99% indicating a well-supported monophyletic relationship. Molecular diversity indices showed high levels of haplotype diversity dominated by private haplotypes, but low nucleotide divergence between haplotypes. The Tajima’s D test and Fu’s Fs test showed negative value, indicating deviations from neutrality and both suggested recent population expansion of mite populations supported by a star-like topology of the isolates in the network analysis. Our genetic data are consistent with a single introduction of NFM infestations and the spread of NFM infestation in Hainan poultry farms and a private haplotype dominance, which suggest that infestations are recycled within the farms and transmission routes are limited between farms. Conclusions To our knowledge, this is the first time a molecular report of NFM in chicken from China including other Asian countries using DNA barcoding. The findings have potential implications with respect to understanding the transmission patterns, emergence and populations trends of parasitic infestations of poultry farms that will help for setting the parameters for integrated pest management (IPM) tactics against mite infestations.