WORKING ON STRANGLES’ LAST GASP

When talking with Dr. John F. Timoney of the UK Gluck Equine Research Center about strangles, one can get a true idea of how many-faceted the study of one disease can be. While most believe disease research delves only into finding cures for illnesses, Dr. Timoney, and other infectious disease researchers like him, is quick to point out there are many questions that need to be answered before—and after—a cure is found. The cure is the goal, he asserts, but the information collected on the way is invaluable for continued research into the spotlighted illness or other diseases.

Timoney began his work on a vaccine for strangles when he was employed at Cornell University. He then moved to the Gluck Center in 1992 and brought his strangles expertise with him. He has continued his work on the vaccine, trying to perfect its performance and finding just the right way to administer it.

Timoney explains that strangles is a highly contagious disease of the tonsillar complex found in the horse’s nose and jowl and caused by the bacteria Streptococcus equi. It is seen primarily in young horses and can be life-threatening to very young foals. A horse owner would see a depressed animal with a depleted appetite, having a temperature of 103° or more, and possibly some watery nasal discharge. In short order, the nasal discharge becomes a purulent excretion, and there is swelling of the jowls and the throat area. Breathing may be labored. What’s happening is that any one of the seven tonsils horses possess--or any combination of them--are infected. The tonsils, which are lymph nodes, swell and develop abscesses that will eventually break open. The abscesses may crowd the trachea, making breathing difficult and swallowing uncomfortable—hence the name of the disease. The horse will lose condition and be unusable for three or four weeks while it recovers. Occasionally, an open abscesses will spill the bacteria to other parts of the horse’s body, causing an extended illness.

The good news about strangles is that it is rarely fatal and the bacteria cannot “live in the environment. A horse may be able to recover without treatment. But, Timoney said, it takes time to cure, and a sick horse is a threat to the health of any other horse, burro or mule which it may come in contact with.

Just how the bacteria gets into the tonsils and how is causes the disease are only two facets that will be addressed by his research. Once these questions are answered, Timoney feels it will be easier to prevent or stem an outbreak. Right now, there are several vaccines for strangles available, but exactly how effective they are is still being debated.

Timoney said ideally, he would like to see a vaccine that only uses the components of the bacteria that will speed the horse’s body into producing the antigens necessary for immunity rather than using a solution with live or modified-live bacteria, as in the currently available vaccines. Just which parts of the bacteria would allow this to happen is another facet of Timoney’s investigation into the mystery of strangles. He also wants to discover which is the best method with which to administer the vaccine. Timoney favors the intranasal application because, he said, it applies the vaccine directly to the area that would be attacked.

Another facet that Timoney hopes to uncover in his quest is how the vaccine’s protective immunity works, once it is viable.

Besides assisting veterinarians and horse owners, Timoney feels his work will benefit other infectious disease researchers at the Gluck Center and elsewhere who are conducting their own investigations into related equine, feline, and porcine illnesses. And even though humans cannot become infected with S. equi, human medicine may benefit from his findings since a somewhat similar condition in people is strep throat.