Lower allergen levels in hypoallergenic Curly Horses? A comparison among breeds by measurements of horse allergens in hair and air samples

Abstract

BackgroundExposure to horses can cause severe allergic reactions in sensitized individuals. The breed, American Bashkir Curly Horse is categorized as hypoallergenic, primarily due to reports of allergic patients experiencing fewer symptoms while handling this special breed. The possible reasons for this phenomenon could be lower allergen production and/or reduced allergen release into the air because of increased sebum content in their skin and hair compared to other breeds. Therefore, the aim of the current study was to compare different horse breeds in relation to allergen content in hair and airborne dust samples.MethodsIn total, 224 hair samples from 32 different horse breeds were investigated. Personal nasal filters were used to collect airborne dust during the grooming of 20 Curly Horses and 20 Quarter Horses. Quantitative analysis of all samples was performed using two newly developed immunoassays for the detection of horse dander (HD) antigens and the major allergen Equ c 1 and the commercial assay for Equ c 4. Results were analyzed using multiple linear regression models for hair samples and the Mann Whitney U test for airborne samples.ResultsHorse antigen and allergen levels differed up to four orders of magnitude between individual animals. Despite enormous variability, levels of HD antigen, Equ c 1 and Equ c 4 in hair were significantly related to the breed and gender combined with the castration status of male animals. Curly Horses had significantly higher concentrations of all three tested parameters compared to the majority of the investigated breeds (medians: 11800 μg/g for HD antigen, 2400 μg/g for Equ c 1, and 258 kU/g for Equ c 4). Tinker Horses, Icelandic Horses and Shetland Ponies were associated with approximately 7-fold reduced levels of HD antigen and Equ c 1, and up to 25-fold reduced levels of Equ c 4 compared to Curly Horses. Compared to mares, stallions displayed increased concentrations of HD antigens, Equ c 1 and Equ c 4 by a factor 2.2, 3.5 and 6.7, respectively. No difference was observed between mares and geldings. No differences in airborne allergen concentrations collected with personal nasal filters during grooming were found between Curly and Quarter Horses.ConclusionBreed and castration status had a significant influence on the antigen and allergen levels of horse hair. However, these differences were smaller than the wide variability observed among individual horses. Compared to other breeds, Curly Horses were not associated with lower allergen levels in hair and in air samples collected during grooming. Our approach provides no molecular explanation why Curly Horses are considered to be hypoallergenic.

Animal Allergens, Endotoxin, and β-(1,3)-Glucan in Small Animal Practices: Exposure Levels at Work and in Homes of Veterinary Staff

“…Allergen levels of Fel d 1, Can f 1, and Bos d 2 were determined using monoclonal antibodies and calibration standards purchased from Indoor Biotechnologies Inc. (Charlottesville, VA, USA) according to protocols described previously for cat and dog ( Sander and Lotz et al , 2016 ) and for cattle ( Zahradnik et al , 2015 ). Equ c 1 concentrations were quantified using an immunoassay based on polyclonal antibodies and naturally-purified Equ c 1 as a standard ( Zahradnik et al , 2018 ). To improve assay sensitivity, the chromogenic substrate ABST [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] was exchanged with the fluorogenic substrate QuantaBlu (ThermoScientific, Rockford, IL, USA).…”

Use of nasal filters for allergen exposure measurements in veterinary practices

“…For the dog allergen, exposure did not differ depending on the number of dogs treated or the duration of contact with dogs. We excluded saturation of the nasal filter membrane due to its binding capacity as a potential explanation, since much higher values were obtained in a study on horse allergens (up to 47,500 ng/filter for Equ c 1 and 4,080 ng/filter for Equ c 4 13) . In the present study, the highest values were approximately 25 ng/filter for Fel d 1 and 38 ng/filter for Can f 1.…”

“…In addition, allergen loads shed by an individual animal can vary enormously. Variations in allergen content of hair up to four orders of magnitude were observed in dogs 22) , horses 13,23) , and cattle 24) of different breeds and sexes. Another factor that could influence the high variability of allergen levels was talking during dust collection, which was not restricted as in other studies 8) .…”

“…This experiment showed that the major allergens from dust mite, cat, dog, and pollen are captured by the nasal filter once present in the dust 12) . Furthermore, the Rhinix nasal filters were successfully used to investigate equine allergen levels released into the air during grooming 13) . However, in this study they were applied under extreme high-exposure conditions, during the same activity, and for the same amount of time (10 min).…”

Assessment of serum allergenspecific IgE levels in horses from Siedlce County, Poland

“…Although some species, such as dogs and horses, may seem to be more prone to allergies than other species, allergic diseases are common in most mammals (Zahradnik et al, 2018;Jania et al, 2020).…”