Equine insect bite hypersensitivity: What do we know?

Schaffartzik, Anna; Hamza, Eman; Janda, Jozef; Crameri, Reto; Marti, Eliane; Rhyner, Claudio

doi:10.1016/j.vetimm.2012.03.017

Cited by 123 publications

(172 citation statements)

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“…Atopic dermatitis in humans and IBH in horses have similar features (Schaffartzik et al, 2012). Polygenic influence in development of IBH in horses has been observed in our study along with other studies.…”

Section: Allergy In Humanssupporting

confidence: 88%

“…Such skin allergic disorders have been observed in many different horse breeds and in other species for instance sheep, cattle, donkey (Correa et al, 2007;Yeruham et al, 1993), dogs (Pucheu-Haston, 2016Chamberlain, 1978) and hippopotamus (Spriggs & Reeder, 2012). IBH is known by different names in different parts of the world: "Queensland itch" in Australia, "Kasen disease" in Japan, "Sweet itch" in Great Britain, "Sommareksem" in Nordic countries, and the similar "Sommerekzem" in Germany (Schaffartzik et al, 2012;Brostrom et al, 1987).…”

Section: Insect Bite Hypersensitivity Backgroundmentioning

confidence: 99%

“…IBH has been described as a type I hypersensitivity reaction with release of histamine and other inflammatory mediators from basophils and mast cells (Jonsdottir et al, 2015). However the involvement of a type IV hypersensitivity reaction has also been suggested (Jonsdottir et al, 2015;Schaffartzik et al, 2012).…”

Section: Insect Bite Hypersensitivity Backgroundmentioning

confidence: 99%

“…The worldwide prevalence of IBH in different horse populations ranges from 3% in Great Britain to 60% in Australia as reviewed in Schaffartzik et al (2012). Culicoides species have not been observed in Iceland.…”

Section: Insect Bite Hypersensitivity Backgroundmentioning

confidence: 99%

“…Culicoides species have not been observed in Iceland. Icelandic horses exported from Iceland to the European continent had IBH prevalence of more than 50% as reviewed in Schaffartzik et al (2012). The estimated prevalence of IBH in Swedish-born Icelandic horses ranged from 6.7% (441 horses used, (Brostrom et al, 1987)) to 8% (1,250 horses used, (Eriksson et al, 2008)).…”

Section: Insect Bite Hypersensitivity Backgroundmentioning

confidence: 99%

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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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Section: Allergy In Humanssupporting

confidence: 88%