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© 2020 Elsevier B.V. All rights reserved., Insect Bite Hypersensitivity (IBH) is a common cutaneous disease, affecting a large number of horses worldwide. Several studies have identified Culicoides spp. saliva as a clinically relevant allergen source. The prevalence of IBH in Portugal, particularly in Lusitano horses, is still not known. However, the environmental characteristics of the national territory are favorable to the activity of Culicoides, and several species of this genus can be found, namely C. imicola and C. obsoletus/C. scoticus. In this study we characterized the Culicoides population present in Lusitano stud farms with a history of IBH. Thirteen stud farms with Lusitano horses were selected in several regions of mainland Portugal for having a previous history of IBH-affected horses, with a minimum of 5 affected horses. Culicoides were collected in May and June 2016 using OVI traps, placed in these stud farms, and we were able to identify several Culicoides species. We could also verify that C. obsoletus/C. scoticus, and C. imicola were the ones most frequently found, but other species like C. pulicaris were also found.

Background Insect bite hypersensitivity (IBH) is the most common seasonal pruritic allergic dermatitis of horses occurring upon insect bites. In recent years, a major role for IL‐31 in allergic pruritus of humans, monkeys, dogs, and mice was acknowledged. Here, we investigate the role of IL‐31 in IBH of horses and developed a therapeutic vaccine against equine IL‐31 (eIL‐31). Methods IL‐31 levels were quantified in allergen‐stimulated peripheral blood mononuclear cells (PBMCs) and skin punch biopsies of IBH lesions and healthy skin from IBH‐affected and healthy horses. The vaccine consisted of eIL‐31 covalently coupled to a virus‐like particle (VLP) derived from cucumber mosaic virus containing a tetanus toxoid universal T‐cell epitope (CuMVTT). Eighteen IBH‐affected horses were recruited and immunized with 300 μg of eIL‐31‐CuMVTT vaccine or placebo and IBH severity score was recorded. Results IL‐31 was increased in PBMCs and exclusively detectable in skin lesions of IBH‐affected horses. Vaccination against eIL‐31 reduced delta clinical scores when compared to previous untreated IBH season of the same horses and to placebo‐treated horses in the same year. The vaccine was well tolerated without safety concerns throughout the study. Conclusion TH2‐derived IL‐31 is involved in IBH pathology and accordingly the immunotherapeutic vaccination approach targeting IL‐31 alleviated clinical scores in affected horses., Equine IL‐31 is detectable in insect bite hypersensitivity (IBH) skin lesions upon insect bites and mediates pruritus by targeting peripheral nerves. IL‐31 is absent in skin biopsies from nonlesional or healthy skin. eIL‐31‐CuMVTT vaccine successfully induces autoantibodies against IL‐31 and reduces lesion scores in horses.

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses, an IgE-mediated reaction to Culicoides midges. Causative Culicoides spp. are not indigenous in Iceland resulting in high prevalence of IBH in horses born in Iceland and exported as compared to Icelandic horses born in a Culicoides rich environment. The aims were (i) to compare IgE levels in sera of IBH-affected horses born in Iceland (n = 47) with horses of the Icelandic breed (n = 23) and of other breeds (n = 27) born in Culicoides infested area; (ii) to investigate if barley could be a useful production system of allergens for IBH immunoassays. IgE binding in sera was tested by ELISA on two recombinant Culicoides allergens, rCul n 3 and rCul n 4, each produced in E. coli, insect cells and barley. Significantly more IgE was detected against all allergens in sera from IBH-affected compared to healthy horses. Icelandic-born Icelandic horses stand out with higher IgE levels against the allergens and higher area under the curve (AUC) on rCul n 4 as compared to the European-born horses. The barley and E.coli produced allergens had very similar performance in distinguishing between IBH-affected and healthy horses.

The objective of this study was to assess the genetic parameters of insect bite hypersensitivity (IBH) in the Old Grey Kladruber horse, an original Czech warmblood horse breed. Insect bite hypersensitivity is a recurrent allergic skin disease affecting horses worldwide. Its etiology is multifactorial. The defect is genetically controlled, and the starting impulse is a bite by midges of the spp. and less frequently spp. Knowledge about the associated genes is limited. Horses were kept by the National Stud in Kladruby (1,146 measurements) and by 10 private breeders (63 measurements). The horses were visually scored by the same inspector over a period of 13 yr from 1996 to 2009. A linear logistic model with a binary variable was used for subsequent statistical analysis. The fixed effects of the farm, year of evaluation, age of evaluation, and sex were significant, and the nonsignificant effect was the intensity of greying. The animals from the National Stud were more strongly affected by IBH than animals from private studs. The National Stud is located near the Labe River, at an altitude of 206 m; there are bottomland pastures in the vicinity, blind river arms, and numerous pools and marshes, and the climate is mild. These conditions are convenient for horse keeping but also for the propagation of . The stallions were less affected than the mares. The occurrence in years of age was influenced by selection; scoring began in the first year of age, and when the young animal was repeatedly positive, it was eliminated from breeding. The estimated h differed significantly from 0, and the direct h were 0.626 in the animal model with a maternal effect, 0.359 in the animal model without a maternal effect, and 0.363 in the animal model without correlation between direct and maternal effect. The maternal h was 0.305. The estimated repeatabilities were 0.636 with a maternal effect, 0.615 without a maternal effect, and 0.623 without correlation. The h of IBH was found to be medium to high, so there is a possibility to reduce the prevalence of IBH by selection.

Culicoides midges are important as vectors of disease, as an irritant with severe effects on human outdoor activities in certain areas and as the cause of insect bite hypersensitivity in domestic animals (most notably horses). Here we report, for the first time, the confirmation of ovine hypersensitivity to Culicoides midges in Hebridean sheep suffering from seasonal allergic skin disease using intradermal allergen testing. The affected sheep formed 40% of the adults in the small flock, and this indication of a potentially high prevalence of a condition with welfare implications is of concern.

Insect bite hypersensitivity (IBH), which is a cutaneous allergic reaction to antigens from Culicoides spp., is the most prevalent skin disorder in horses. Misdiagnosis is possible, as IBH is usually diagnosed based on clinical signs. Our study is the first to employ IgE levels against several recombinant Culicoides spp. allergens as an objective, independent, and quantitative phenotype to improve the power to detect genetic variants that underlie IBH. Genotypes of 200 Shetland ponies, 127 Icelandic horses, and 223 Belgian Warmblood horses were analyzed while using a mixed model approach. No single-nucleotide polymorphism (SNP) passed the Bonferroni corrected significance threshold, but several regions were identified within and across breeds, which confirmed previously identified regions of interest and, in addition, identifying new regions of interest. Allergen-specific IgE levels are a continuous and objective phenotype that allow for more powerful analyses when compared to a case-control set-up, as more significant associations were obtained. However, the use of a higher density array seems necessary to fully employ the use of IgE levels as a phenotype. While these results still require validation in a large independent dataset, the use of allergen-specific IgE levels showed value as an objective and continuous phenotype that can deepen our understanding of the biology underlying IBH. The research leading to these results has received funding fromthe EuropeanUnion's Seventh Framework Programme managed by REA-Research Executive Agency, http://ec.europa.eu/research/rea (FP7/2007-2013) under grant agreement No. 606142.

Adverse reactions to insects occur in both human and veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in all species. In this position paper, we summarize the current knowledge on insect allergy induced via stings, bites, inhalation or ingestion, and compare reactions in companion animals to those in people. With few exceptions, the situation in human insect allergy is better documented than in animals. We focus on a review of recent literature and give overviews of the epidemiology and clinical signs. We discuss allergen sources and allergenic molecules to the extent described, and aspects of diagnosis, prophylaxis, management and therapy. © 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Equine insect bite hypersensitivity (IBH), commonly known as sweet itch or summer eczema, is a frustrating recurrent skin disease in the equine industry involving an immune reaction to the bites of Culicoides spp. midges. To investigate the impact of IBH in the field, an exploratory pilot study was conducted with equine stakeholders in one region of central England. Nine semi-structured, face-to-face interviews were conducted with horse owners and an equine veterinarian. The aim was to gain an understanding of experiences with IBH, and to gauge opinions on the value of the various management strategies horse owners use to control IBH. Awareness of IBH was generally high, particularly in those individuals who had previous experience with the condition. Those with previous experience of IBH commented on the significant effect on daily routines, and the associated cost implications. Most participants supported an integrated approach to hypersensitivity management, and this most commonly involved a combination of physical barriers and chemical repellents, but sometimes included feed supplementation. Overall, attitudes towards IBH suggested that the condition is a notable welfare and economic concern for stakeholders, but veterinary involvement tended to only be in more severe cases. Further research is required in the future to improve understanding, management and potential treatment of this condition.

Background Many common and relevant diseases affecting equine welfare have yet to be tested regarding structural variants such as copy number variations (CNVs). CNVs make up a substantial proportion of total genetic variability in populations of many species, resulting in more sequence differences between individuals than SNPs. Associations between CNVs and disease phenotypes have been established in several species, but equine CNV studies have been limited. Aim of this study was to identify CNVs and to perform a genome-wide association (GWA) study in Friesian horses to identify genomic loci associated with insect bite hypersensitivity (IBH), a common seasonal allergic dermatitis observed in many horse breeds worldwide. Results Genotypes were obtained using the AxiomÂŽ Equine Genotyping Array containing 670,796 SNPs. After quality control of genotypes, 15,041 CNVs and 5350 CNV regions (CNVRs) were identified in 222 Friesian horses. Coverage of the total genome by CNVRs was 11.2% with 49.2% of CNVRs containing genes. 58.0% of CNVRs were novel (i.e. so far only identified in Friesian horses). A SNP- and CNV-based GWA analysis was performed, where about half of the horses were affected by IBH. The SNP-based analysis showed a highly significant association between the MHC region on ECA20 and IBH in Friesian horses. Associations between the MHC region on ECA20 and IBH were also detected based on the CNV-based analysis. However, CNVs associated with IBH in Friesian horses were not often in close proximity to SNPs identified to be associated with IBH. Conclusions CNVs were identified in a large sample of the Friesian horse population, thereby contributing to our knowledge on CNVs in horses and facilitating our understanding of the equine genome and its phenotypic expression. A clear association was identified between the MHC region on ECA20 and IBH in Friesian horses based on both SNP- and CNV-based GWA studies. These results imply that MHC contributes to IBH sensitivity in Friesian horses. Although subsequent analyses are needed for verification, nucleotide differences, as well as more complex structural variations like CNVs, seem to contribute to IBH sensitivity. IBH should be considered as a common disease with a complex genomic architecture.

Background Many common and relevant diseases affecting equine welfare have yet to be tested regarding structural variants such as copy number variations (CNVs). CNVs make up a substantial proportion of total genetic variability in populations of many species, resulting in more sequence differences between individuals than SNPs. Associations between CNVs and disease phenotypes have been established in several species, but equine CNV studies have been limited. Aim of this study was to identify CNVs and to perform a genome-wide association (GWA) study in Friesian horses to identify genomic loci associated with insect bite hypersensitivity (IBH), a common seasonal allergic dermatitis observed in many horse breeds worldwide. Results Genotypes were obtained using the Axiom® Equine Genotyping Array containing 670,796 SNPs. After quality control of genotypes, 15,041 CNVs and 5350 CNV regions (CNVRs) were identified in 222 Friesian horses. Coverage of the total genome by CNVRs was 11.2% with 49.2% of CNVRs containing genes. 58.0% of CNVRs were novel (i.e. so far only identified in Friesian horses). A SNP- and CNV-based GWA analysis was performed, where about half of the horses were affected by IBH. The SNP-based analysis showed a highly significant association between the MHC region on ECA20 and IBH in Friesian horses. Associations between the MHC region on ECA20 and IBH were also detected based on the CNV-based analysis. However, CNVs associated with IBH in Friesian horses were not often in close proximity to SNPs identified to be associated with IBH. Conclusions CNVs were identified in a large sample of the Friesian horse population, thereby contributing to our knowledge on CNVs in horses and facilitating our understanding of the equine genome and its phenotypic expression. A clear association was identified between the MHC region on ECA20 and IBH in Friesian horses based on both SNP- and CNV-based GWA studies. These results imply that MHC contributes to IBH sensitivity in Friesian horses. Although subsequent analyses are needed for verification, nucleotide differences, as well as more complex structural variations like CNVs, seem to contribute to IBH sensitivity. IBH should be considered as a common disease with a complex genomic architecture. Electronic supplementary material The online version of this article (10.1186/s12863-018-0657-0) contains supplementary material, which is available to authorized users.

Insect bite hypersensitivity (IBH) is a type I allergy of horses with production of IgE and release of inflammatory mediators. It is caused by bites of midges of the genus Culicoides. The disease is a recurrent dermatitis characterized by pruritic skin and hair loss, which can result in secondary infections. All breeds of horses can be affected, but horses born in Iceland and exported are more frequently affected than Icelandic horses born abroad. Allergens have been identified at the molecular level from three Culicoides spp., C. sonorensis, C. nubeculosus and C. obsoletus. They have all been produced in E. coli and some in insect cells and barley. The aim of the study was to develop immunotherapy for IBH using vaccination with purified allergens in adjuvants and a method to treat horses via the oral mucosa with transgenic barley expressing allergens. Different injection routes and adjuvants were tested for development of prophylactic immunotherapy. Healthy Icelandic horses were vaccinated intradermally or intralymphatically with a small amount of purified allergens with or without a Th1 adjuvant. The intradermal and the intralymphatic vaccinations with adjuvant resulted in significant generation of allergen specific IgG1 and IgG4/7, the highest response being observed following intralymphatic vaccination. Furthermore, the antibodies produced after intralymphatic vaccination with the allergens in an adjuvant were able to partly inhibit binding of IgE to the allergens, an important mechanism of allergen immunotherapy. The intralymphatic route was employed to compare the immune response induced after vaccination with purified allergens in Alum alone or in a mixture of Alum and Monophosphoryl lipid A (MPLA). The vaccinated horses mounted a strong IgG1 and IgG4/7 response and the antibodies had the capacity to block the binding of IgE to the allergens. The adjuvant groups only differed with regard to the cytokine response but not in the antibody response. Compared to unvaccinated control horses, the IFNγ and IL-10 induced following in vitro restimulation of peripheral blood mononuclear cells (PBMCs) with an allergen was significantly higher in the Alum/MPLA but not in the Alum group. This indicated an increased Th1/Treg response after vaccination with Alum/MPLA. A spiral bit and a barley flour mixture were developed to treat horses via the mucosa of the mouth. Healthy Icelandic horses were treated with barley expressing the Cul n 2 allergen. The horses receiving the Cul n 2 barley mounted a specific IgG1 and IgG4/7 response in the sera and saliva. The antibodies induced were able to partly inhibit binding of IgE to Cul n 2 as well as to Cul o 2, the corresponding allergen from C. obsoletus. For evaluation of the benefit of immunotherapy as well as to confirm the diagnosis of IBH it is important to have recombinant allergens with similar three-dimensional structure and post-translational modification to the native proteins which can be easily purified. Barley grains are an excellent source of proteins and ideal for stable storage. Two allergens produced in barley showed similar performance in ELISA to that of the corresponding proteins expressed in E. coli and insect cells. In conclusion, intralymphatic vaccination with purified allergens in the adjuvant mixture Alum/MPLA is a promising approach for development of a prophylactic and probably also therapeutic immunotherapy against IBH. Furthermore, a first study has demonstrated that oral immunotherapy with barley expressing allergens could be an attractive alternative to conventional allergen immunotherapy, avoiding the expensive purification of recombinant allergens and the need of injection., Sumarexem er ofnæmi af gerð I í hrossum með framleiðslu á IgE mótefnum sem leiða til losunar á bólguþáttum. Ofnæmið orsakast af biti smámýs af ættkvísl Culicoides. Sumarexem er ítrekuð húðbólga og einkennist af kláða, hárlausum svæðum, sáramyndun og jafnvel sýkingum í sárunum. Útfluttir íslenskir hestar fá sumarexem í um 50% tilfella, séu þeir óvarðir á flugusvæðum, en önnur hestakyn og íslenskir hestar fæddir á flugusvæðum fá sumarexem í tíðninni 5-10%. Ofnæmisvakar úr þremur smámýs tegundum, C. sonorensis, C. nubeculosus og C. obsoletus hafa verið skilgreindir, tjáðir í E.coli og nokkrir í skordýrafrumum og byggi. Markmiðið með verkefninu var að þróa ónæmismeðferð gegn sumarexemi; bólusetningu með hreinsuðum ofnæmisvökum í ónæmisglæðum og meðhöndlun um munnslímhúð með erfðabreyttu byggi sem tjáir ofnæmisvaka. Við þróun á ofnæmisvakasértækri ónæmismeðferð voru mismunandi sprautunarstaðir og ónæmisglæðar prófaðir. Heilbrigðir íslenskir hestar voru sprautaðir í húð og í eitla með litlu magni af ofnæmisvökum með eða án Th1 stýrandi glæðis. Bólusetning í eitla og í húð með ónæmisglæði örvaði myndun á sértækum IgG1 og IgG4/7 mótefnum. Bólusetning í eitla með glæði gaf ívíð sterkara svar og mótefnin sem mynduðust hindruðu að hluta til bindingu IgE við ofnæmisvaka. Í næstu tilraun voru íslenskir hestar sprautaðir í eitla með ofnæmisvökum í Alum eða blöndu af Alum og Monophosphoryl lipid A. Bólu-setningin örvaði sterka IgG1 og IgG4/7 mótefnasvörun sem hindruðu bindingu IgE við ofnæmisvaka. Munur á ónæmissvörun hópanna var mælanlegur í boðefnasvari í kjölfar örvunar á hvítfrumum en ekki í mótefnasvari. Marktækt meiri IFNγ og IL-10 framleiðsla var hjá Alum/MPLA hópnum samanborið við óbólusetta viðmiðunar hesta, þessi munur sást ekki hjá Alum hópnum. Þetta bendir til að Alum/MPLA blandan hvetji Th1/Tstjórnfrumu miðað svar. Þróuð voru byggmél og byggblanda til að meðhöndla hross um munnslímhúð. Heilbrigðir íslenskir hestar voru meðhöndlaðir með byggi sem tjáir ofnæmisvakann Cul n 2. Í kjölfar meðhöndlunar mældust sérvirk IgG1 og IgG4/7 mótefni í sermi og munnvatni. Þau gátu að hluta til hindrað bindingu IgE við Cul n 2 en einnig við Cul o 2 sem er sambærilegt prótein úr C. obsoletus. Mikilvægt er að hafa endurraðaða ofnæmisvaka sem auðvelt er að hreinsa, hafa svipaða þriðja stigs byggingu og eftirbreytni og náttúrulegu próteinin þegar árangur ónæmismeðferðar er metinn og klínísk greining sjúkdómsins staðfest. Byggfræ eru vel til þess fallin að framleiða prótein og fyrir langvarandi geymslu proteina á stöðugu formi. Tveir ofnæmisvakar framleiddir í byggi voru jafn vel fallnir til notkunar í ELISA mótefnaprófi og samsvarandi vakar framleiddir í E.coli og skordýrafrumum. Niðurstöðurnar sýna að bólusetning í eitla með hreinum ofnæmisvökum í blöndu af Alum/MPLA er vænleg leið í þróun á fyrirbyggjandi meðferð gegn sumarexemi og mögulega líka afnæmingu. Enn fremur fengust vísbendingar um að meðhöndlun um slímhúð munns með byggi sem tjáir ofnæmisvaka gæti verið góður valkostur. Þannig væri komist hjá vandasamri sprautun og kostnaðarsamri próteinhreinsun., Rannís, Eimskipasjóður Háskóla Íslands, Rannsóknasjóður Háskóla Íslands, Framleiðnisjóður landbúnaðarins, Hrossaræktarsamtök Suðurlands, VETSUISSE.

Despite extensive research in recent years into the aetiopathogenesis of sweet itch (more appropriately termed insect bite hypersensitivity or IBH) there have been no revelations in options for treatment. Where new treatments have become available they have not been supported by published evidence of efficacy leaving clinicians uncertain as to their relative merits. The absence of universally effective treatments has left the door open for a plethora of products to line the tack shop shelves frequently leaving the veterinary profession side-lined when it comes to managing the condition. This is regrettable as advice on effective management and avoidance strategies is likely to be infinitely more valuable than any treatments employed after clinical signs have developed.

Allergies are common in horses. It is important to identify and correct as many factors as possible to control pruritus and make the patient comfortable. Culicoides hypersensitivity is a common component in allergic horses. The main treatment continues to be rigorous fly control and avoidance of insect bites. Environmental allergies are best addressed by early identification of the offending allergens and formulation of allergen-specific immunotherapy to decrease the need for rescue medications. Food allergy is best managed with food avoidance. Urticaria is one of the manifestations of allergic disease wherein detection of the triggering cause is essential for management.

SummaryReasons for performing study Equine summer eczema, also known as insect bite hypersensitivity, affects horses recurrently during summer months. The treatment of this allergic pruritus is difficult and therefore there is a need for efficacious treatments. Autoserum therapy, based on the use of autogenous serum that is specifically prepared for oral administration and given when the animal shows clinical signs has been introduced recently. Lipids are thought to be responsible for the effect of this therapy. Objectives The main aim of this study was to analyse the phospholipid content of autogenous serum preparations and to further assess whether these preparations have different lipid profiles depending on the clinical status of the horse. The hypothesis is that the major serum phospholipids typical of the horse are present in the autoserum preparation. Study design Descriptive controlled clinical study. Methods Sera were collected from 10 affected and 6 healthy horses, prepared in a similar fashion and the lipids contained in the resulting autoserum preparations were analysed by electrospray ionisation mass spectrometry. Results The major phospholipid classes detected were phosphatidylcholine, sphingomyelin, phosphatidic acid and traces of lysophosphatidylcholine. Horses with summer eczema had significantly abundant concentrations of phosphatidylcholine (P = 0.042) and sphingomyelin (P = 0.0017) in comparison with healthy horses, while the concentration of phosphatidic acid was significantly higher in healthy horses (P = 0.0075). Conclusions The autoserum preparation contains minute amounts of the main serum phospholipids in differing concentrations in healthy horses and horses with an allergic skin disease.

Background: Lipids have become an important target for searching new biomarkers typical of different autoimmune and allergic diseases. The most common allergic dermatitis of the horse is related to stings of insects and is known as insect bite hypersensitivity (IBH) or summer eczema, referring to its recurrence during the summer months. This intense pruritus has certain similarities with atopic dermatitis of humans. The treatment of IBH is difficult and therefore new strategies for therapy are needed. Autoserum therapy based on the use of serum phospholipids has recently been introduced for horses. So far, serum lipids relating to these allergic disorders have been poorly determined. The main aim of this study was to analyse phospholipid profiles in the sera of horses with allergic dermatitis and in their healthy controls and to further assess whether these lipid profiles change according to the clinical status after therapy. Methods: Sera were collected from 10 horses with allergic dermatitis and from 10 matched healthy controls both before and 4 weeks after the therapy of the affected horses. Eczema horses were treated with an autogenous preparation made from a horse's own serum and used for oral medication. Samples were analysed for their phospholipid content by liquid chromatography coupled to a triple-quadrupole mass spectrometer (LC-MS). Data of phospholipid concentrations between the groups and over the time were analysed by using the Friedman test. Correlations between the change of concentrations and the clinical status were assessed by Spearman's rank correlation test. Results: The major phospholipid classes detected were phosphatidylcholine (PC), sphingomyelin (SM), phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Eczema horses had significantly lower total concentrations of PC (p

Made available in DSpace on 2013-09-27T14:54:12Z (GMT). No. of bitstreams: 1 WOS000307003200027.pdf: 1432667 bytes, checksum: 5f377edb961c4f77f492a35467962181 (MD5) Previous issue date: 2012-01-01 Made available in DSpace on 2013-09-30T18:26:16Z (GMT). No. of bitstreams: 1 WOS000307003200027.pdf: 1432667 bytes, checksum: 5f377edb961c4f77f492a35467962181 (MD5) Previous issue date: 2012-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:37:17Z No. of bitstreams: 1 WOS000307003200027.pdf: 1432667 bytes, checksum: 5f377edb961c4f77f492a35467962181 (MD5) Made available in DSpace on 2014-05-20T13:37:17Z (GMT). No. of bitstreams: 1 WOS000307003200027.pdf: 1432667 bytes, checksum: 5f377edb961c4f77f492a35467962181 (MD5) Previous issue date: 2012-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) In this study, the clinical and histopathological aspects of insect bite hypersensitivity (IBH) were assessed in horses. For this purpose, 12 horses with histopathologically confirmed cases of IBH of the skin were selected. The 12 animals were from 10 stud farms located in different municipalities of the state of São Paulo, Brazil. The main clinical findings included severe pruritus, alopecia and signs of irritability. The lesions were diffuse and predominantly dorsal, with the mane, tail and face most commonly affected. Histologically, perivascular lympho-histiocytic and eosinophilic dermatitis were also evident. Other findings included orthokeratotic hyperkeratosis, acanthosis and spongiosis. Thus, it was concluded that IBH could be diagnosed in horses through the combined use of clinical and epidemiological data and histopathological findings. Univ Estadual Paulista, Dept Clin Vet, Fac Med Vet & Zootecnia, UNESP, Botucatu, SP, Brazil UNESP, Dept Patol, Fac Med Botucatu, Botucatu, SP, Brazil Univ Estadual Paulista, Dept Clin Vet, Fac Med Vet & Zootecnia, UNESP, Botucatu, SP, Brazil UNESP, Dept Patol, Fac Med Botucatu, Botucatu, SP, Brazil

Insect bite hypersensitivity (IBH), an allergic reaction to the saliva of Culicoides, occurs in all horse breeds and is a severe problem. In this study, we aimed at exploring whether exterior conditions, such as duration of allergenic exposure during the first summer and age of the horses at the time of import, influence the development of IBH. Additionally, data were analyzed regarding the period IBH started after birth and after import. Datasets for 582 horses were collected. The horses were locally born Icelandic horses and horses of other breeds with IBH, as well as imported Icelandic horses, both affected and nonaffected. For locally born horses, time of birth and duration of allergen exposure during the first summer had no influence on the prevalence of IBH. The disease started mostly in their third year of life. The majority of the imported horses affected caught IBH during their first year in Central Europe. Older imported horses seemed to develop IBH quicker than younger animals. Animals imported in their first winter are exposed to the allergen when they are at least 7 months old. They experienced approximately the same low risk of developing IBH as locally bred horses. The risk of IBH increased with the horses’ age at import. From our data, we conclude that the period to develop successful immune tolerance goes beyond the perinatal phase and is longer than formerly supposed.

Summary The Friesian horse breed is a beautiful breed for showing, riding and driving. However, some clinical problems seem to have a higher incidence in the Friesian breed compared to other breeds and this raises suspicions that these clinical entities may have a genetic basis.

Pruritus is not a disease but a physiological protective alarm system which might react in a pathological destructive fashion, depending on the triggering cause. In horses a frequently suspected reason for destructive pruritus is an allergic disease termed “summer eczema”, “sweet itch”, or “insect bite hypersensitivity”. However, there are numerous alternatives provoking similar clinical symptoms. Additional problems for proper diagnosis and appropriate therapy cause “mixed” forms of diseases: On one hand different causes might occur simultaneously and on the other hand one cause might act via different pathomechanisms. For example: Black flies might provoke strong itching just by their injected saliva when biting (simuliotoxicosis) without any underlying allergy. However, a horse might be allergic against such saliva components. Thus, the intense pruritus is now caused by type I-allergy mechanisms within the framework of a “summer eczema”. This paper compromises two parts. Part 1: Definition and clinical forms of “summer eczema”. Part 2 (to follow in issue 3/2011 of this journal): Pathomechanisms of “summer eczema” including relevant diagnostics plus a list of most of the relevant alternative causes for pruritus and/or “sweet itch”-like symptoms.

Equine summer skin diseases are primarily dominated by insect-related conditions, although outdoor allergens and the sun are responsible for the large proportion of the remaining commonly presented problems. This article reviews the aetiology, presentation and current diagnostic and therapeutic approaches to common insect-induced dermatoses including insect bite hypersensitivity (sweet itch) and harvest mite infestation.

Summary Equine summer eczema, the most common allergic skin disease of the horse, is notoriously difficult to treat with available methods. In the present study, 343 horses were treated with an autogenous serum preparation made from their highly diluted sera. This work was a continuation of the earlier, randomised and placebo controlled study on the autoserum therapy that showed a significant, positive clinical effect and was carried out on a series of horses in 1997–98. The main aim of the present study was to collect long-term information from the owners on this therapy. In the period from 1997–2008, 70% of the horses benefited from the treatment and 16% did not, while 14% of owners could give no clear opinion. After a 5 year follow-up, horses treated with autoserum had significantly milder clinical signs of summer eczema than before this treatment. No harmful side effects were found. An autoserum preparation was shown to be a feasible alternative in the treatment of equine summer eczema.

Intradermal tests using a Culicoides nubeculosus extract have proven unreliable for diagnosis of equine insect bite hypersensitivity (IBH) in the Netherlands. The aim of this study was to evaluate the diagnostic value of an extract derived from the Dutch species C. obsoletus and C. pulicaris. Thirteen pairs of horses were tested, each pair consisting of one horse with IBH and the other a healthy control. Each horse was injected intradermally with 0.1 mL of three concentrations of Culicoides whole body extract (1 : 1000 w/v, 1 : 10,000 w/v and 1 : 25,000 w/v), histamine solution (0.01 mg/mL, positive control) and phosphate-buffered saline (negative control). Skin responses were evaluated after 30 min and at 1, 4 and 24 h. At all time points the absolute wheal diameter elicited by Culicoides extract 1 : 1000 w/v was significantly larger (P

Allergic diseases occur in most mammals, although some species such as humans, dogs and horses seem to be more prone to develop allergies than others. In horses, insect bite hypersensitivity (IBH), an allergic dermatitis caused by bites of midges, and recurrent airway obstruction (RAO), a hyperreactivity to stable born dust and allergens, are the two most prevalent allergic diseases. Allergic diseases involve the interaction of three major factors: (i) genetic constitution, (ii) exposure to allergens, and (iii) a dysregulation of the immune response determined by (i) and (ii). However, other environmental factors such as infectious diseases, contact with endotoxin and degree of infestation with endoparasites have been shown to influence the prevalence of allergic diseases in humans. How these factors may impact upon allergic disease in the horse is unknown at this time. The 3rd workshop on Allergic Diseases of the Horse, with major sponsorship from the Havemeyer Foundation, was held in Holar, Iceland, in June 2007 and focussed on immunological and genetic aspects of IBH and RAO. This particular venue was chosen because of the prevalence of IBH in exported Icelandic horses. The incidence of IBH is significantly different between Icelandic horses born in Europe or North America and those born in Iceland and exported as adults. Although the genetic factors and allergens are the same, exported adult horses show a greater incidence of IBH. This suggests that environmental or epigenetic factors may contribute to this response. This report summarizes the present state of knowledge and summarizes important issues discussed at the workshop.

The objective of this study was to investigate clinical signs indicating diseases with known or suspected hereditary components like equine sarcoid, insect bite hypersensitivity, osteochondrosis, allergic airway diseases, podotrochleosis, prognatism and wind-sucking in the franches-montagnes horse. We performed a clinical examination on 702 three-year-old, privately owned franches-montagnes horses, which were shown at the Swiss-Field-Tests in 2004. With the help of the owners a questionnaire on health, environment and feeding habits of the animals was completed. In 11.9% of the horses, sarcoids were detected, 6.2% carried one tumor and 5.7% had several. The prevalence was higher in chestnuts (16.6%) than in bays (10.1%). The prevalence of sarcoids in offspring from sires with known sarcoids (data from Station-Tests 1994-2005) was not significantly higher than in descendants from stallions without a known history of sarcoids. Clinical signs of insect bite hypersensitivity were only found in six horses (0.9%). In 12.0% hoof abnormalities like brittle horn, ring hoofs or hoof cracks of different degrees were recorded. The angle between hoof base and hoof wall was 56.7 +/- 0.1 degrees, the average hoof width was 13.7 +/- 0.3 cm in the front feet. For both of these measures we found no significant difference between left and right feet. With the exception of a high sarcoid prevalence, our results indicate that the franches-montagnes horse is a healthy breed overall.

Insect bite hypersensitivity (IBH) is a seasonal recurrent skin allergy of horses caused by IgE-mediated reactions to allergens present in the saliva of biting insects of the genus Culicoides, and possibly also Simulium and Stomoxys species. In this work we show that protein microarrays containing complex extracts and pure proteins, including recombinant Culicoides allergens, can be used as a powerful technique for the diagnosis of IBH. Besides the obvious advantages such as general profiling and use of few microliters of samples, this microarray technique permits automation and allows the generation of mathematical models with the calculation of individual risk profiles that can support the clinical diagnosis of allergic diseases. After selection of variables on influence on the projection (VIP), the observed values of sensitivity and specificity were 1.0 and 0.967, respectively. This confirms the highly discriminatory power of this approach for IBH and made it possible to attain a robust predictive mathematical model for this disease. It also further demonstrates the specificity of the protein array method on identifying a particular IgE-mediated disease when the sensitising allergen group is known.

Genetic factors involved in susceptibility to insect bite hypersensitivity (IBH) in Belgian Warmblood horses (BWP) were investigated. Data relating to 3409 horses were collected using a questionnaire, administered to owners during sport competitions, BWP breeding days, breeder visits and after phone calls. Horses were classified as IBH-affected or unaffected, based on two ‘disease classifiers’: a lifetime record, based on owner information (life_status) and another based on whether or not the horse was showing clinical signs at the time of questioning (clin_status). IBH prevalence was 10% based on life_status, and 6.2% based on clin_status. The heritabilities estimated using threshold animal models varied from 0.65 to 0.78 on the underlying scale (0.18 to 0.26 on the observed scale). These research findings indicate that susceptibility to IBH is a heritable trait in BWP. publisher: Elsevier articletitle: Genetic parameters and estimated breeding values of insect bite hypersensitivity in Belgian Warmblood horses journaltitle: The Veterinary Journal articlelink: http://dx.doi.org/10.1016/j.tvjl.2015.08.012 content_type: article copyright: Copyright © 2015 Elsevier Ltd. All rights reserved. ispartof: The Veterinary Journal vol:206 issue:3 pages:420-422 ispartof: location:England status: published

Insect bite hypersensitivity (IBH) is a common allergic skin disease in horses, caused by biting insects of the Culicoides spp. In The Netherlands, Culicoides spp. of the Obsoletus complex are the most important midges involved in IBH. The aim of the present study was to identify and quantify associations between several endogenous (host) and exogenous (environmental) factors and immunoglobulin E (IgE) reactivity against Obsoletus complex-derived whole body extract or seven recombinant allergens, measured by ELISA. Data from 143 Icelandic horses and 177 Shetland ponies were analysed using multivariable models. In addition, the relationship between IgE reactivity and severity of clinical signs in IBH-affected horses was examined. Positive correlations were found between Obsoletus complex-specific IgE and severity of clinical signs. Disease status (IBH affected or control), breed and the interaction between IBH status and breed were significantly associated with IgE reactivity against several Obsoletus complex allergens. Significantly greater IgE reactivity was seen in IBH-affected horses compared to controls. The differences in IgE values between cases and controls were most pronounced in Icelandic horses. Shetland pony controls had significantly greater IgE reactivity compared to Icelandic horse controls, while differences in IgE values comparing Shetland pony cases and Icelandic horse cases were not significant. Severity of clinical signs and IgE reactivity in IBH-affected horses against several Obsoletus complex allergens appeared to be related. Consideration of the factors associated with Obsoletus complex-specific IgE in horses might further improve interpretation and accuracy of IgE ELISA test results within these breeds, although further research is required.

Insect bite hypersensitivity (IBH) is an allergic dermatitis in horses caused by the bites of Culicoides species. The aim of the present study was to evaluate the applicability of whole body extracts of C. obsoletus (the main species found feeding on horses in the Netherlands), C. nubeculosus (rarely found in The Netherlands) and C. sonorensis (typical for North America) for diagnosis of IBH in horses in The Netherlands. Blood and serum samples of 10 clinically confirmed IBH affected and 10 healthy control horses were used to evaluate the IgE titers (ELISA) against the Culicoides whole body extracts of the three Culicoides species. Basophil degranulation was assessed by histamine release test (HRT) after stimulation with these extracts at 5, 0.5 and 0.05 μg/ml. IBH affected horses had significantly higher IgE titers against C. obsoletus than against C. nubeculosus and C. sonorensis. Furthermore, C. obsoletus induced significantly higher histamine release in whole blood of IBH affected horses compared to the other extracts at 0.5 μg/ml. Western blot data revealed IgE binding to many proteins in C. obsoletus extract. This interaction was absent or weak in C. nubeculosus and C. sonorensis extracts for IBH affected horses. Results on individual level indicate that the HRT is more sensitive than ELISA in diagnosing IBH. However, ELISA is more practical as a routine test, therefore the ELISA was further evaluated using C. obsoletus extract on 103 IBH affected and 100 healthy horses, which resulted in a test sensitivity and specificity of 93.2% and 90.0%, respectively. The IgE ELISA readings enabled the analysis of the predicted probability of being IBH affected. From an optical density 450 nm value of 0.33 onwards, the probability of IBH affected was more than 0.9. The results presented in this paper show that the use of native Culicoides spp. that feed on horse, is important for improved diagnosis and that the described ELISA based on C. obsoletus can be used routinely to diagnose IBH in countries where this species is the main Culicoides feeding on horses.

Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Swedish born Icelandic horses were tested for genetic association. These horses had previously been genotyped on the Illumina Equine SNP50 BeadChip, which made it possible to ensure that our study did not suffer from the effects of stratification. The second population consisted of 106 unaffected and 80 IBH-affected Exmoor ponies. We show that variants in the MHC class II region are associated with disease susceptibility (praw = 2.34 × 10−5), with the same allele (COR112:274) associated in two separate populations. In addition, we combined microsatellite and sequencing data in order to investigate the pattern of homozygosity and show that homozygosity across the entire MHC class II region is associated with a higher risk of developing IBH (p = 0.0013). To our knowledge this is the first time in any atopic dermatitis suffering species, including man, where the same risk allele has been identified in two distinct populations. Electronic supplementary material The online version of this article (doi:10.1007/s00251-011-0573-1) contains supplementary material, which is available to authorized users.

The task of this thesis is to elaborate study of insect bite hypersensitivity incidence by the Old Kladrubian white horses. At the beginning of the thesis, problems of congenital disorders in general are summarized, such as origin of the disorders and the forming factors. Further, the insect bite hypersensitivity in horses as an allergic disorder with genetic predisposition is described. Original research concerns with analysis of all actual data of insect bite hypersensitivity incidence in population of Old Kladrubian horse and with analysis of selected horses´ progeny. Incidence of the disorder depends significantly on father of the foal and year of birth. No difference in morbidity between genders of foals was found. At the end the practical breeder´s advices are summarized.

Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis of horses caused by bites of insects such as Culicoides or Simulium spp. The aim of the present study was to compare the IgE-binding pattern of sera of IBH-affected horses to Culicoides nubeculosus and Simulium vittatum salivary gland extracts (SGE). Individual IgE responses to proteins of S. vittatum and C. nubeculosus SGEs were evaluated in 15 IBH-affected and three healthy horses on immunoblots. Fourteen out of the 15 IBH-affected but none of the healthy horses showed individual IgE binding patterns to seven and six main protein bands in C. nubeculosus and S. vittatum SGE, respectively. These 14 sera showed IgE-binding to proteins from SGE of both C. nubeculosus and S. vittatum, but they reacted with fewer protein bands derived from S. vittatum than from C. nubeculosus SGE. Sera showing IgE-binding to a 32 kDa band from C. nubeculosus always bound to a 32 kDa band from S. vittatum. Similarly, all sera binding to a 70 kDa band from C. nubeculosus reacted with a corresponding band in S. vittatum SGE. The 70 kDa bands from S. vittatum and C. nubeculosus were identified by mass spectrometry as heat shock protein-70-cognate-3.