Summer eczema in exported Icelandic horses: influence of environmental and genetic factors

Björnsdóttir, Sigríður; Sigvaldadóttir, Jakobína; Broström, Hans; Langvad, Birgitte; Sigurdsson, A

doi:10.1186/1751-0147-48-3

Cited by 67 publications

(69 citation statements)

References 13 publications

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“…However, IBH can also occur in the form of an outbreak; the study by Schild, Ferreira and Soares (2003) reported the presence of the disease in 7% of the animals on a property located in Rio Grande do Sul, Brazil. Björnsdóttir et al (2006) found that the greatest risk factor for IBH is exposure to Culicoides biting midges, especially for animals kept on fertilized or humid pastures. In the present study, the two animals imported from the United States (USA) developed the disease one year after arriving in Brazil, and IBH has been shown to be the most common skin allergy in horses in certain regions of the USA (GREINER, 1995;FRIBERG;LOGAS, 1999).…”

Section: Discussionmentioning

confidence: 99%

“…In the present study, the two animals imported from the United States (USA) developed the disease one year after arriving in Brazil, and IBH has been shown to be the most common skin allergy in horses in certain regions of the USA (GREINER, 1995;FRIBERG;LOGAS, 1999). Thus, epidemiological surveys must consider the origin of the animals, especially whether they have been imported, because animals imported from countries such as Iceland, where the presence of Culicoides biting midges has not been reported and the occurrence of this disease has not been described (BJÖRNSDÓTTIR et al, 2006;HALLAMAA, 2009;KNOTTENBELT, 2009), have been shown to be more sensitive than native animals to the development of severe hypersensitivity (BJÖRNSDÓTTIR et al, 2006;HALLAMAA, 2009). The identification of the insect species responsible for the clinical manifestations of IBH described in this study was not possible because the clinical care of the animals took place at a referral center that was far removed from the properties of origin.…”

Section: Discussionmentioning

confidence: 99%

“…IBH has a worldwide distribution (McCAIG, 1973;LARSSON;TROEDSSON, 1987;SCOTT;MILLER, 2003;BJÖRNSDÓTTIR et al, 2006;HALLAMAA, 2009) without showing a predilection for gender, coat color or age (SCOTT; MILLER, 2003;HALLAMAA, 2009). In Brazil, Culicoides biting midges and black flies have been found parasitizing horses (CALVÃO-BRITO et al, 1998), and insects belonging to the Culicoides genus have been shown to be responsible for this disease in sheep (SOUZA et al, 2005;CORRÊA et al, 2007;BARBOSA et al, 2011) and horses (PORTUGAL et al, 1996;SOARES, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Clinical and histopathological aspects of the insect bite hypersensitivity in horses

et al. 2012

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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. Key words: Dermatopathology, allergic dermatitis, Culicoides, pruritus, horses ResumoForam avaliados os aspectos clínicos e histopatológicos da hipersensibilidade à picada de insetos (HSPI) em equinos. Para isso, foram selecionados 12 cavalos em que a suspeita clínica de HSPI foi confirmada através do exame histopatológico da pele. Os 12 animais eram provenientes de dez haras localizados em diferentes municípios do estado de São Paulo. Os principais achados clínicos incluíam prurido intenso, alopecia e sinais de irritabilidade. As lesões eram difusas e predominantemente dorsais sendo a crina, a cauda e a face geralmente acometidas. Histologicamente evidenciou-se dermatite perivascular linfohistiocítica e eosinofílica. Outros achados incluíam hiperceratose ortoceratótica, acantose e espongiose. Pode-se concluir que o diagnóstico de HSPI em equinos pode ser realizado através da associação dos dados clínico-epidemiológicos com os achados histopatológicos.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Clinical and histopathological aspects of the insect bite hypersensitivity in horses

et al. 2012

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“…A similar prevalence of 6.3% was reported for Icelandic horses born in Germany, by Reiher and Bjö rnsdó ttir (2004), whereas Lange et al (2005) found a higher prevalence of 16% among German-born Icelandic horses. The prevalence of summer eczema among horses exported from Iceland to any of these countries is considerably higher: 26% to 72% has been reported (Halldó rsdó ttir and Larsen, 1991;Lange et al, 2005;Bjö rnsdó ttir et al, 2006). Horses born in Iceland are not exposed to Culicoides early in life and will not have the possibility to develop a normal immunity response to its antigen.…”

Section: Prevalencementioning

confidence: 99%

Genetic analysis of insect bite hypersensitivity (summer eczema) in Icelandic horses

Eriksson

Grandinson

Fikse³

et al. 2008

Animal

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There is a lack of knowledge about the genetic background of eczema due to insect bite hypersensitivity, also called summer eczema, in horses. The condition is known in several horse breeds and countries and it causes reduced welfare of the horse and economic losses to the owner. The aim of this study was to estimate genetic parameters for summer eczema in Swedishborn Icelandic horses. A questionnaire was sent to owners of horses sired by stallions with more than 50 offspring born in Sweden between 1991 and 2001. Variance components of summer eczema classified as healthy, mild, moderate or severe were estimated using the threshold methodology with sire models. In addition, summer eczema was analysed as a binary trait (healthy v. affected). The analyses included 1250 horses sired by 33 stallions. The prevalence of summer eczema was 8%, with a range of 0% to 30% in different paternal half-sib groups. Offspring of dams suffering from eczema had a higher risk of developing eczema. The heritability for severity of summer eczema was estimated at 0.3 (s.d. , 0.2) with a threshold sire model. In contrast to the age of the horse, different geographic areas and gender were significantly associated with severity of the eczema. We conclude that genetic selection could decrease the prevalence of summer eczema among Swedish-born Icelandic horses. The amount and quality of data are, however, crucial for the possibility to introduce a genetic evaluation of summer eczema. The symptoms should be classified in several classes according to severity, and this classification could be made by the horse owner.

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“…The clinical symptoms of IBH include intense itching leading to scratching, hair loss, scaling, thickening of skin, open wounds and secondary infections (Schurink et al, 2011;Bjornsdottir et al, 2006). The clinical symptoms can in general be recognized by horse owners themselves.…”

Section: Clinical Symptomsmentioning

confidence: 99%

Genetics of equine insect bite hypersensitivity and genetic diversity in horses

Shrestha¹

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Genetic variation contributing to the phenotypic variation was utilized in this thesis to understand the genetic background of a complex trait IBH, and to understand genetic diversity and relationships between various horse populations.IBH is the most common skin allergic disorder in horses, caused by bites of midges, predominantly Culicoides species. It affects various horse breeds worldwide. With no effective treatment, IBH degrades horse health and causes economic loss. In this thesis, we used genome-wide SNPs to identify regions contributing to genetic variance of IBH susceptibility. We also investigated influence of increased number of horses and dense SNPs on identification of genomic regions associated to IBH susceptibility. Multiple genomic regions with small effects were observed in Studies I-III. Interesting genomic regions in the Icelandic horse population across the studies I and II, was observed on chromosomes 1, 7, 10, 15 and 17. The percentage of the genetic variance explained by top ten windows increased from 3.07% (Study I) to 6.56% (Study II). Novel genomic regions were identified when number of Icelandic horses was increased in Study II. Using dense SNPs on the Exmoor pony population we identified novel genomic regions, on chr 8, associated to IBH susceptibility, though with borderline significance.In Study IV, pre-conceived understanding about evolutionary history of horse populations matched obtained results from investigation of genetic relationships within Dutch warmblood populations (pairwise mean FST ≤ 0.070), and within pony-like populations (pairwise mean FST ≤ 0.078). Horse populations with similar genetic background might share similar genetic components for IBH susceptibility. The Friesian horse population had lowest diversity (mean inbreeding coefficients: fi: 30.4%, fiROH= 22.2%) in Study IV and was genetically distinct (FST ranged from 0.13 to 0.17). This might be a result of a history of several population bottlenecks and selection on a closed breeding scheme. Low diversity in immunity related genes, observed in the Friesian horse population, might have led to increased prevalence of IBH. Similarly, low susceptibility of IBH in a warmblood population, KWPN sport horse population might be due to high genetic diversity ( i f =-6.9%). High genetic diversity in KWPN sport horse population might be a result of an open breeding scheme and interbreeding with other warmblood populations.

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Summer eczema in exported Icelandic horses: influence of environmental and genetic factors

Cited by 67 publications

References 13 publications

Clinical and histopathological aspects of the insect bite hypersensitivity in horses

Clinical and histopathological aspects of the insect bite hypersensitivity in horses

Genetic analysis of insect bite hypersensitivity (summer eczema) in Icelandic horses

Genetics of equine insect bite hypersensitivity and genetic diversity in horses

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