Natural latex rubber could be a significant allergen capable of triggering severe asthma in some horses, research findings suggest.
Latex is historically associated with the equine environment in the form of artificial surfaces on arenas and racetracks. Indeed, many arena surfaces throughout the world contain components of natural rubber.
The surprise finding was made in the biggest ever study into the causes of severe equine asthma. The research revealed asthma-related links with more than 113 substances.
Lead researcher Sam White, who carried out the study for the Royal Agricultural University and the University of Nottingham in Britain, found that natural rubber latex was among “the most surprising and significant” of several new allergens present in the dust horses breathe.
White used advanced computing power to assess more than 400 potential allergens in more than 130 severely asthmatic and healthy horses, working with research groups in Switzerland, France, Canada and the United States.
The research revealed many similarities with human allergic asthma and confirmed previously unlinked bacteria, fungi, mite and pollen allergens.
Indeed, many of the allergens identified have previously been implicated in human allergic asthma, but not previously assessed in the horse.
But the allergy risk from Latex was the standout finding.
“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 humans,” White says.
“These early results show it could be linked to respiratory problems in horses too, although it is too early to make a firm conclusion based on these data and further work is needed.”
Antibodies specific for proteins derived from latex were identified in some of the horses affected by severe asthma, pointing to an allergic reaction.
The researchers, in their paper published in the journal Scientific Reports, said further work is required to establish the exposure levels of latex in the horse’s daily environment, latex inhalation reactivity tests, epidemiological studies and further hypersensitivity confirmation.
“At present, exposure should be considered a potential risk to the respiratory health of the horse,” the study team said.
The research used mathematical modelling to enable the diagnosis of severe equine asthma from a blood sample, preventing the reliance on more invasive diagnostic techniques currently employed.
White, now a Lecturer in Equine Science at Nottingham Trent University, said the identification of new allergens would improve allergen avoidance and help in the development of future diagnostic tests and therapies.
About 14 percent of horses in the northern hemisphere are affected by severe asthma.
The research programme was supported by the Fred and Marjorie Sainsbury Charitable Trust and Haygain, the Morris Animal Foundation, the Swiss National Science Foundation and Stiftung Forschung für das Pferd.
White, S.J., Moore-Colyer, M., Marti, E. et al. Antigen array for serological diagnosis and novel allergen identification in severe equine asthma. Sci Rep 9, 15170 (2019) doi:10.1038/s41598-019-51820-7.