Scientific Reports, a Nature Research publication, publishes new research identifying new allergens associated with severe equine asthma.

It is common knowledge that the inhalation of stable ‘dust’ in predisposed horses results in SEA (previously known as recurrent airway obstruction/heaves/COPD).

“We know this ‘dust’ contains bacteria, fungi, pollen and arthropods (e.g. mites), but what we wanted to establish was the precise allergen that elicit this prevalent and debilitating condition” said researcher Samuel White, who conducted the study under the supervision of Professor Meriel Moore-Colyer of the Royal Agricultural University and Professors Duncan Hannant and Marcos Alcocer of the University of Nottingham.

Using advances in computational and robotic technologies, White developed a novel method which enabled the simultaneous assessment of almost 400 potential allergen in over 130 SEA-affected and healthy horses. This was the widest-scale allergen assessment in SEA horses to date and revealed many similarities with human allergic asthma.

The results confirmed allergen previously identified in hay (e.g. Aspergillus fumigatus), as well as revealing a plethora of unidentified bacteria, fungi and arthropod. Previous research by Moore-Colyer et al (2016)* has proven high temperature steaming of hay with a Haygain removes the airborne dust from the breathing zone of the horse, and is thus effective against these allergens.

White’s work also identified pollen allergens, which had not previously been associated with SEA.

“The most significant and surprising allergens associated with SEA were from natural rubber latex,” White said. “Latex is historically associated with the equine environment in the form of artificial surfaces on arenas and racetracks.”

The high level of respirable dust associated with training on these surfaces has already been linked with chronic bronchitis, inflammation and oxidative stress in riding instructors, and latex has long been associated with a variety of respiratory conditions in the human. These results indicate that exposure to latex may be detrimental to the respiratory health of the horse.

Read more: New Allergens Associated with Severe Equine Asthma

by Genevieve Rajewski, Tufts University

Pixie, a thirteen-year-old Shetland pony, is only about one-fifth the size of most horses seen for asthma at Tufts Equine Center. That doesn't make his breathing problems any less significant, though.

In the year and a half since Pixie was adopted, his asthma attacks—in which his sides heave from desperately trying to draw each breath—have become more common and severe. "It's awful," said owner Sara Smith, whose three-year-old daughter loves being led around on the gentle gelding's back. "Once the heaves start, it's just so uncontrollable."

Cummings School veterinarian Melissa Mazan, V93—who is caring for Pixie as part of a clinical trial evaluating a possible new treatment for equine asthma—stroked the sorrel pony's nose and nodded sympathetically. She has been working on the challenging condition of equine asthma for her entire professional career, and knows how hard it hits the horses and their owners.

"We have learned a lot about how to diagnose equine asthma and its molecular mechanisms, but we treat this condition almost exactly like we did when I started out more than twenty years ago," Mazan said. "And anyone trying to treat an asthmatic horse often ends up stuck between a rock and a hard place."

Read more: Testing a New Therapy for Horses Struggling to Breathe