Science-in-brief: Latex in riding arenas and racetracks identified as a risk factor for equine respiratory health.

This study investigates severe equine asthma (sEA), a significant health risk in horses similar to human asthma, identifying latex found in riding arenas and racetracks as a potential risk factor. The team developed a protein microarray to identify allergens causing sEA and discovered a strong correlation between allergen-specific IgE measured in bronchoalveolar lavage fluid and serum. A highlight of their findings is the identification of proteins derived from natural rubber latex as potential triggers of sEA.

About Severe Equine Asthma

• sEA, previously known as RAO, COPD, and heaves, is a chronic respiratory disease in horses similar to asthma in humans.
• It is a severe condition mostly affecting older stabled horses but it can also impact the performance of younger competition horses.
• Diagnosis of sEA is challenging due to the varying clinical history and previous exposure to respiratory allergens and environmental antigens.

The Role of Immunoglobulin E (IgE)

• The allergic response in sEA is associated with increased IgE against environmental proteins.
• The importance of IgE in the pathogenesis of the condition was confirmed using histamine release assays and allergen-specific IgE analyses of bronchoalveolar lavage fluid (BALF) and serum.

Comprehensive Protein Microarray

• The researchers developed a protein microarray comprising extracts and pure proteins from various protein families predominantly of fungi, bacteria, pollen, and arthropods.
• They tested a total of 384 potential allergens using this array.
• The research was conducted in two phases, with the second phase involving a larger group of horses across France, Switzerland, USA, and Canada.

Findings of the Study

• The study demonstrated that serum IgE could be used as a biomarker for sEA diagnosis.
• It highlighted the identification of new allergens from pollen, bacteria, mold, and arthropod proteins that caused sEA symptoms.
• The researchers found that many horses with sEA had IgE antibodies specific for proteins derived from natural rubber latex, or Hevea brasiliensis (Hev b).
• Latex is common in horse environments such as riding surfaces and racetracks, thus its presence poses a significant risk to the respiratory health of horses.

The study’s breakthrough lies in its ability to provide new insights into the allergens causing sEA and presenting an accurate diagnostic approach. This could lead to tailored management practices and the development of allergen-specific immunotherapy.