WHAT’S NEW in the veterinary world?
Allergies can plague both humans and horses. Peter Green MRCVS reports on the latest related research
UNFORTUNATELY, some people are allergic to horses. Just as some humans sneeze and wheeze and itch and have watery eyes when they come into contact with cats, others have the same reaction to horses. The allergy can be quite severe, even debilitating.
The American Bashkir Curly horse is a breed derived from a handful of mustangs that were seen with unusual curly coats in the early and mid-20th century in the American Midwest. Although called Bashkirs, they are not related to the Russian Bashkir horse, which may also have a curly coat.
One of the promoted features of these horses is that they are said to be hypoallergenic; it is claimed that people with allergies to all other horses do not react when they are with the American Curlies.
Scientists in the USA have been researching this, to see if it is true. They took 141 patients with known allergies to horses and exposed them to the curly coated horses; the subjects rode the horses, groomed them and spent time in the stables with them.
In more than 1,300 hours of exposure, there were only 72 allergic events, mostly when patients first met the horses and mostly transient. If these patients had been with other breeds, they would all have reacted all the time. The research proved that curly coated horses are indeed hypoallergenic.
The scientists admit that they do not know why this is. What was even more amazing was that the allergic patients became less reactive to other horses after their interactions with the curly coated horses. It seems that spending time with these unusual horses actually reduces the allergy to other horses. It is unclear how, but more research is under way.
ASTHMA INSIGHTS
HORSES too suffer from allergies. The most common is the respiratory allergy to stable dust and mould spores that causes equine asthma, or obstructive airway disease. Affected horses wheeze and cough when exposed to the spores or particles in the air. It’s common; severe cases become “broken winded”.
The disease arises because the internal surface of the airways, sensitive to inhaled particles, reacts by producing more mucus. The sensitivity also results in tightening of the muscle around the airways, constricting each tiny air tube. This reaction is under the control of the nerves and nerve receptors in the walls of the airways.
Vets in Canada made an interesting discovery. They looked very carefully at the airway tissue from horses with severe asthma in the course of post-mortem examinations and compared it with the same tissues from horses that had died without any signs of asthma.
What they found was that when horses develop the respiratory allergy to the dust and spores, it is not just that their nerve receptors are more sensitive, but that the actual number of nerves and receptors increases as the disease progresses.
It’s a real double whammy – not only do horses with asthma have more sensitive nerve receptors in their airways, but increasingly have more of them with time.