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Background Psoroptic mange, caused by infestation with the ectoparasitic mite, Psoroptes ovis , is highly contagious, resulting in intense pruritus and represents a major welfare and economic concern for the livestock industry Worldwide. Control relies on injectable endectocides and organophosphate dips, but concerns over residues, environmental contamination, and the development of resistance threaten the sustainability of this approach, highlighting interest in alternative control methods. However, development of vaccines and identification of chemotherapeutic targets is hampered by the lack of P. ovis transcriptomic and genomic resources. Results Building on the recent publication of the P. ovis draft genome, here we present a genomic analysis and transcriptomic atlas of gene expression in P. ovis revealing feeding- and stage-specific patterns of gene expression, including novel multigene families and allergens. Network-based clustering revealed 14 gene clusters demonstrating either single- or multi-stage specific gene expression patterns, with 3075 female-specific, 890 male-specific and 112, 217 and 526 transcripts showing larval, protonymph and tritonymph specific-expression, respectively. Detailed analysis of P. ovis allergens revealed stage-specific patterns of allergen gene expression, many of which were also enriched in “fed” mites and tritonymphs, highlighting an important feeding-related allergenicity in this developmental stage. Pair-wise analysis of differential expression between life-cycle stages identified patterns of sex-biased gene expression and also identified novel P. ovis multigene families including known allergens and novel genes with high levels of stage-specific expression. Conclusions The genomic and transcriptomic atlas described here represents a unique resource for the acarid-research community, whilst the OrcAE platform makes this freely available, facilitating further community-led curation of the draft P. ovis genome.

Background Psoroptic mange, caused by Psoroptes ovis mites, is affecting Belgian Blue cattle’s welfare and production potential. The Belgian Blue cattle—known for its high degree of muscling, low feed conversion ratio and high beef quality—is highly susceptible for this disease. Results In this study, we phenotyped 1975 Belgian Blue cattle from more than 100 different groups on commercial beef farms for their psoroptic mange susceptibility. Substantial individual differences were observed within these management groups, with lesion extent differences up to ± 15%. Animal models showed that estimated heritabilities were low for lesion extent and severe lesion extent (0.07 and 0.09, respectively) and 0.12 for the number of mites. A genome wide association study for mange susceptibility revealed signals on BTA6, BTA11, BTA15 and BTA24. In these regions, candidate genes GBA3 , RAG2 , and TRAF6 were identified. Conclusions Despite the challenges in phenotyping for psoroptic mange due to the timing of screening, the continuous evolution of lesions and different management conditions, we successfully conducted a study on the genetic susceptibility to psoroptic mange in Belgian Blue cattle. Our results clearly indicate that psoroptic mange is under polygenic control and the underlying candidate genes should be studied more thoroughly. This is the first study providing candidate genes for this complex disease. These results are already valuable for Belgian Blue breeding, however, further research is needed to unravel the architecture of this disease and to identify causal mutations.

Psoroptes ovis is a mite species that feeds on sheep, cattle, other ungulates, rabbits, and horses, which can develop into a severe exudative dermatitis known as psoroptic mange. The macrocyclic lactone (ML) family of acaricides are commonly used to control psoroptic mange. However, certain strains of cattle and sheep mites have developed resistance against MLs, which has led to reduced treatment efficacy and even treatment failure. Here we investigated the genetic basis of ML resistance in P. ovis mites collected from cattle across Belgium. We compared gene expression between susceptible and resistant mites before and after exposure to ivermectin and genetic diversity between a single susceptible and resistant populations. We generated chromosomal genome assemblies of P. ovis derived from sheep and cattle respectively and correlated genomic diversity of susceptible and resistant P. ovis populations sampled across Belgium. Gene expression data revealed constitutive over-expression of a cytochrome P450 monooxygenase (CYP) gene and two tandemly located UDP-glucuronosyltransferase (UGT) genes among others. On investigation of the genomic data, we observed copy number variation at both loci in population genomic data. The CYP gene is not amplified in the susceptible population but occurs in multiple copies in all resistant populations and is associated with a peak in F st between resistant and susceptible populations indicative of selection. By contrast, the two UGT genes are massively and tandemly amplified in all populations including the susceptible dataset with weaker F st between populations than the amplified CYP gene. Hence, distinct mechanisms of amplification and gene regulation are occurring at these putative resistance loci in P. ovis.

An outbreak of Psoroptes sp.-caused mange was detected in a llama herd of Larcas, Jujuy province, Argentina. Infested llamas showed alopecia, erythema, hyperpigmentation, hyperkeratosis, and inflammation of the ear pinnae, as well as crusts and serous, serosanguineous, or purulent drainage with unpleasant smell in the external ear canal. Microscopic evaluation of skin scrapings revealed 0.5- to 0.7-mm-long acari identified as Psoroptes sp. based on their morphology. Histology showed a typical allergic reaction with perivascular to periadnexal mixed inflammatory infiltrate. Phylogenetic tree analysis showed that the cytochrome c oxidase subunit I gene sequences analyzed from the sampled acari clustered into a single P. ovis clade including sequences isolated from rabbits and bighorn sheep, with P. natalensis as a sister taxon that infested bighorn sheep from the USA. Phylogenetic analysis of cytochrome b sequences showed three well-supported clades, one of which contained the sequences of the Larcas llamas and US bighorn sheep isolates. This is the first report on P. ovis infestation of llamas raised in their original location. Investigations on mange etiological agents acting on South American camelids and their distribution are necessary to implement control strategies to mitigate the negative impacts of these parasitic infections.

Species delimitation of Psoroptes spp. and identity of the parasite in water buffaloes remain poorly defined. In this study, Psoroptes infestation on three water buffalo farms in Egypt was examined based on morphometric characteristics, especially the opisthosomal setae of adult male mites. Clinical investigations showed that 28% (196/700) of the sampled animals had mange infestation. Microscopic examinations of 80 skin scrapings indicated the occurrence of Psoroptes mites in 17 (21.3%) samples, Sarcoptes mites in 27 (33.7%) samples, and the concurrence of both in 36 (45.0%) samples. Morphologically, the Psoroptes parasite was identified as Psoroptes natalensis. DNA sequence analysis of the second internal transcribed spacer (ITS2) in 11 representative samples confirmed the diagnosis and suggested the presence of a distinct variety of Psoroptes natalensis in Egypt.

Background Psoroptes ovis , the causative agent of psoroptic mange, affects a wide range of domestic and wild animals, causing substantial economic losses and threatening wildlife survival. However, the underlying pathogenesis of this ectoparasitic disease remains poorly understood. Methods In this study, we comprehensively characterized the sequence conservation and excretory–secretory properties of P. ovis calreticulin (PsoCRT) using sequence alignment, immunoblotting, and immunofluorescence assays. To investigate the functional impact of recombinant PsoCRT (rPsoCRT), we conducted in vitro studies assessing its effects on keratinocyte proliferation, migration, differentiation, and the expression of immune regulatory factors. In addition, we employed rabbit ear intradermal injections of rPsoCRT to histologically observe tissue changes and confirm alterations in the expression profiles of immune regulatory factors. Results PsoCRT was expressed across all developmental stages of P. ovis , with peak expression observed in adult males. Notably, PsoCRT was excreted and secreted into the host epidermis, primarily localizing within the stratum granulosum and spinosum. Intriguingly, sera from rabbits infested with P. ovis did not recognize PsoCRT. In vitro studies revealed that rPsoCRT significantly inhibited keratinocyte proliferation and migration, promoted differentiation, and upregulated the expression of interleukin (IL)-1β, IL-6, IL-36, C–C motif chemokine ligand 27 (CCL27), and vascular endothelial growth factor (VEGF) in vitro, without altering the levels of interferon (IFN)-γ or tumor necrosis factor (TNF)-α. In vivo, rabbit ear intradermal injections of rPsoCRT induced epidermal cell differentiation, immune cell infiltration, and an upregulation of IL-6, CCL27, and VEGF expression. Conclusions PsoCRT disrupted the physical and immune barriers of keratinocytes, leading to skin dysfunction and facilitating a microenvironment conducive to P. ovis parasitization, thereby highlighting its important role in the pathogenesis of psoroptic mange. Graphical abstract

Background The efficacy of fluralaner for the treatment of Otodectes cynotis infestations in dogs and cats was evaluated after oral (dogs) or topical administration (dogs and cats). Twenty-four dogs and sixteen cats were experimentally infested with O. cynotis and randomly allocated to equal sized groups ( n  = 8/group). Dog groups were treated once, either orally with fluralaner at a minimum dose of 25 mg/kg body weight, topically with fluralaner at a dose of 25 mg/kg body weight or topically with saline solution (control). Cat groups were treated once, either topically with fluralaner at a dose of 40 mg/kg body weight or topically with saline solution. Ears of all animals were examined otoscopically for live visible mites and the amount of debris and cerumen before, and 14 and 28 days after treatment. Twenty-eight days after treatment, animals were sedated and both ears were flushed to obtain the total number of live mites per animal. The efficacy was calculated, based on the results of the ear flushing, by comparing mean live mite counts in the fluralaner treated groups versus the saline solution treated group. Results A single topical treatment of cats with fluralaner reduced the mean mite counts by 100% ( P  < 0.001) at 28 days after treatment. Similarly, a single oral or topical treatment of dogs with fluralaner reduced the mean mite counts by 99.8% ( P  < 0.001) at 28 days after treatment. Cats treated topically with fluralaner had no mites visible during otoscopic examination at either 14 or 28 days after treatment. All dogs treated orally or topically with fluralaner had no mites visible during otoscopic examination at 28 days after treatment. At 14 days after treatment, only 1–2 mites were visible in three dogs (oral treatment: 2 dogs, topical treatment: 1 dog). All fluralaner-treated animals showed improvement in the amount of cerumen exudation compared with observations performed before treatment. No treatment related adverse events were observed in any dogs or cats enrolled in these studies. Conclusions In this study, fluralaner administered topically to cats and orally or topically to dogs was highly effective against Otodectes cynotis mite infestations.

Parasites and obesity are health problems worldwide. Rabbits are production animals yielding one of the healthiest meats, also taking advantage of skin, hair, limbs and excreta. It is among the most frequent pets in some countries and widely used as animal model in research. Psoroptes cuniculi is a mite of high transmission rate, affecting welfare and production and obesity causes multiple metabolic, endocrine and immunological disorders, being an emerging problem in domestic animals. Obesity and acarosis are prolonged stressors, modifying the activity of the hypothalamic-pituitary-adrenal axis that can induce metabolic and behavioral disorders. Alterations caused by comorbidities could be similar to or different from those induced by each morbidity separately. We analyzed the influence of obesity on the infection degree with P . cuniculi and on behavior and production. Rabbit does induced to obesity were infected and mated; behaviors in the open field test, obesity estimation indices and productive parameters at delivery and weaning were analyzed. The acarosis induced a decrease in feed intake and a decrease in body weight, a decrease in locomotor, exploratory and chinning behaviors in normal weight and obese does. The infection induced 23% mortality at birth, obesity 45% and comorbidity 74%, while in normal weight rabbits a 6.5% was observed. Weight gain from birth to weaning was lower in the comorbid group, reaching a litter weight of 4.5±0.13 kg in healthy normal weight does and 2.6±0.67 kg in comorbid does. The disturbances induced by the comorbidity were magnified in both behavioral and productive parameters.

Some classifications recognize a number of species in the scab-mite genus, Psoroptes, mites that are of considerable importance in livestock production and veterinary medicine. However, modern studies suggest that populations from some host species are not morphologically or genetically distinct, creating taxonomic confusion with older names, which treated mites from different hosts as separate species. We review the taxonomy and nomenclature of the genus and the two oldest binomens, most recently known as Psoroptes ovis and Psoroptes equi. Prior authors have attributed these names to various authorities, with most attributing both names to Hering (Nova Acta Phys-Med Acad Caesar Leopold-Carol Nat Curios 18(2):573–624, 1838). In particular, the priority between these names was recently a point of contention, with P. ovis being treated as junior synonym of P. equi. A review of all relevant nineteenth and twentieth century publications indicates, however, that these binomens should be cited as P. ovis (Viborg in Veterinair-Selskabets Skrifter 2:139–152, 1813) and P. equi (Raspail in Bull gener Theraput Med Chir 7:169–184, 1834), with the former having priority over the latter assuming their conspecificity. We also clarify attribution of the authorship and the type species of the genus Psoroptes.