The same ELA class II risk factors confer equine insect bite hypersensitivity in two distinct populations

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

Genetics of Skin Disease in Horses

Equine skin diseases are common, causing increased costs and reduced welfare of affected horses.Genetic testing, if available, can complement early detection, disease diagnosis, and clinical treatment and offers horse breeders the possibility to rule out carrier status. The mechanisms of complex disease can be investigated by using the latest state-of-the-art genomic technologies. Genome-based strategies may also serve as an efficient and cost-effective strategy for the management of the disease severity levels, with particular interest in complex traits such as insect bite hypersensitivity, chronic progressive lymphedema, and melanoma

Genetics of Skin Disease in Horses

Equine skin diseases are common, causing increased costs and reduced welfare of affected horses.Genetic testing, if available, can complement early detection, disease diagnosis, and clinical treatment and offers horse breeders the possibility to rule out carrier status. The mechanisms of complex disease can be investigated by using the latest state-of-the-art genomic technologies. Genome-based strategies may also serve as an efficient and cost-effective strategy for the management of the disease severity levels, with particular interest in complex traits such as insect bite hypersensitivity, chronic progressive lymphedema, and melanoma.status: publishe

The Labour Progression Study (LaPS): duration of labour following Zhang's guideline and the WHO partograph - a cluster randomised trial

Objective: To investigate labour duration in different phases of labour when adhering to Zhang’s guideline for labour progression compared with the WHO partograph. Design: A secondary analysis of a cluster randomised controlled trial. Setting: Fourteen Norwegian birth care units, each with more than 500 deliveries per year constituted the clusters. Participants: A total of 7277 nulliparous women with singleton foetus in a cephalic presentation and spontaneous onset of labour at term were included. Intervention: Seven clusters were randomised to the intervention group that adhered to Zhang’s guideline (n = 3972) and seven to the control group that adhered to the WHO partograph (n = 3305) for labour progression. Measurements: The duration of labour from the first registration of cervical dilatation (≥ 4 cm) to the delivery of the baby and the duration of the first and second stages of labour; the time-to-event analysis was used to compare the duration of labour between the two groups after adjusting for baseline covariates. Findings: The adjusted median duration of labour was 7.0 h in the Zhang group, compared with 6.2 h in the WHO group; the median difference was 0.84 h with 95% confidence interval [CI] (0.2–1.5). The adjusted median duration of the first stage was 5.6 h in the Zhang group compared with 4.9 h in the WHO group; the median difference was 0.66 h with 95% CI (0.1–1.2). The corresponding adjusted median duration of the second stage was 88 and 77 min; the median difference was 0.18 h with 95% CI (0.1–0.3). Key Conclusions: The women who adhered to Zhang’s guideline had longer overall duration and duration of the first and second stages of labour than women who adhered to the WHO partograph. Implications for practice: : Understanding the variations in the duration of labour is of great importance, and the results offer useful insights into the different labour progression guidelines, which can inform clinical practice

The Labor Progression Study: The use of oxytocin augmentation during labor following Zhang's guideline and the WHO partograph in a cluster randomized trial

Introduction: This study aims to investigate the use of oxytocin augmentation during labor in nulliparous women following Zhang’s guideline or the WHO partograph. Material and methods: This is a secondary analysis of a cluster randomized controlled trial in 14 birth care units in Norway, randomly assigned to either the intervention group, which followed Zhang’s guideline, or to the control group, which followed the WHO partograph, for labor progression. The participants were nulliparous women who had a singleton full-term fetus in a cephalic presentation and spontaneous onset of labor, denoted as group 1 in the Ten Group Classification System. Results: Between December 2014 and January 2017, 7277 participants were included. A total of 3219 women (44%) were augmented with oxytocin during labor. Oxytocin was used in 1658 (42%) women in the Zhang group compared with 1561 (47%) women in the WHO group. The adjusted relative risk for augmentation with oxytocin was 0.98, 95% CI; 0.84 to 1.15; P=0.8 in the Zhang versus WHO group, with an adjusted risk difference of −0.8 %, 95% CI; −7.8 to 6.1. The participants in the Zhang group were less likely to be augmented with oxytocin prior to 6 centimeters of cervical dilatation (24%) compared with participants in the WHO group (28%), with an adjusted relative risk of 0.84, 95% CI; 0.75 to 0.94; P=0.003. Oxytocin was administrated almost 20 minutes longer in the Zhang group than in the WHO group, with an adjusted mean difference of 17.9, 95% CI; 2.7 to 33.1; P=0.021 minutes. In addition, 19% of the women in the Zhang group and 23% in the WHO group were augmented with oxytocin without being diagnosed with labor dystocia. Conclusions: Although no significant difference in the proportion of oxytocin augmentation was observed between the two study groups, there were differences in how oxytocin was used. Women in the Zhang group were less likely to be augmented with oxytocin prior to 6 centimeters of cervical dilatation. The duration of augmentation with oxytocin was longer in the Zhang group than in the WHO group

Data from: Genome-wide association study of insect bite hypersensitivity in Swedish-born Icelandic horses

Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses and is caused by biting midges, mainly of the genus Culicoides. The disease predominantly comprises a type I hypersensitivity reaction, causing severe itching and discomfort that reduce the welfare and commercial value of the horse. It is a multifactorial disorder influenced by both genetic and environmental factors, with heritability ranging from 0.16 to 0.27 in various horse breeds. The worldwide prevalence in different horse breeds ranges from 3% to 60%; it is more than 50% in Icelandic horses exported to the European continent and approximately 8% in Swedish-born Icelandic horses. To minimize the influence of environmental effects, we analyzed Swedish-born Icelandic horses to identify genomic regions that regulate susceptibility to IBH. We performed a genome-wide association (GWA) study on 104 affected and 105 unaffected Icelandic horses genotyped using Illumina® EquineSNP50 Genotyping BeadChip. Quality control and population stratification analyses were performed with the GenABEL package in R (λ = 0.81). The association analysis was performed using the Bayesian variable selection method, Bayes C, implemented in GenSel software. The highest percentage of genetic variance was explained by the windows on X chromosomes (0.51% and 0.36% by 73 and 74 mb), 17 (0.34% by 77 mb), and 18 (0.34% by 26 mb). Overlapping regions with previous GWA studies were observed on chromosomes 7, 9, and 17. The windows identified in our study on chromosomes 7, 10, and 17 harbored immune system genes and are priorities for further investigation

SNP information

This file contains information on SNPs

Information on samples

This file contains information on phenotype, gender, region, age, sire and dam for 209 horses