Horses working on artificial surfaces in arenas or on racetracks might be exposed to pollutants that can impact respiratory health. Early research suggested that latex could be one of many allergens that causes severe equine asthma [White, S.J.; Colyer-Moore, M.; Marti, E.; et al. Antigen array for serological diagnosis and novel allergen identification in severe equine asthma. Scientific Reports 2019, 9 (1):15170; doi. org/10.1038/s41598-019-51820-7].
The Morris Animal foundation is funding research into this topic. Equine asthma is a real concern in the horse world, with as many as 14% of horses—no matter the breed—affected in the Northern Hemisphere.
The researchers used a comprehensive IgE microarray to examine which environmental allergens might be present to create an inflammatory response in horses. On blood tests from 138 sporthorses, they tested 384 extracts and proteins of the equine environment. The horses in the study were from the United States, Canada, Switzerland and France, across a wide range of environmental conditions.
A normal array of expected causal allergens were identified: pollen, mold and insect proteins. But what was not expected was to find natural rubber latex as a possible allergen—four of the five significant allergens were, in fact, latex proteins.
The other significant protein identified is derived from Aspergillus fumigatus, which is a fungus associated with severe equine asthma.
The study further reported that latex is not just present on artificial training surfaces but also circulates in the air of urban environments, in part as a result of wear on car tires. Natural rubber is a material that is commonly incorporated into arena surfaces to improve locomotion and limit musculoskeletal injury.
Latex has been associated with human respiratory disease. In fact, it is not uncommon for riding instructors to experience lung inflammation and chronic bronchitis, possibly from latex-containing respirable dust in the arena.
Further research is ongoing to identify exposure levels of latex to the horses and the specifics about how latex impacts lung function in latex-sensitive horses. Defining the risk also enables efforts to be taken to limit latex exposure in equine environments.
