Vaccine in the future?
Considerable progress is being made toward developing effective vaccines against this infection based on understanding
how R. equi causes disease and identifying the key immunogen(s), Prescott says. "I would expect to see one within the next few years."
Mary Hondalus, DVM, University of Georgia, is studying the use of a particular strain of R. equi (a strain that requires riboflavin supplementation in order to grow) to create an immune response. The particular non-virulent
strain is described as a live-attenuated riboflavin auxotropic strain.
"There are a lot of approaches to develop a vaccine. To use attenuated strains of bacteria is what Dr. Hondalus is doing,"
Hines says. "We are trying to do some DNA-vaccine work here at WSU. I think a vaccine is a long way off. You just have to
try different things. You try something and you modify it, it just has to be an experimental approach. The problem with all
these studies is that you have to immunize foals. The big question is: Can you prime them very early in life to respond appropriately
since neonates are so unique? Some researchers suggest that it is not possible. To me, that's just speculation. You have to
try and see. Certainly, it will be a challenge. Can you get a foal to respond the way you want, is the big question."
R. equi is a huge killer, especially in Florida and Kentucky, where the climate and density of horses on breeding farms is optimal
for the disease. Some of these farms have many cases, and it is very insidious.
"The big reason they see so much of it is that they have the concentration of animals, the big numbers of foals," Hines explains.
"Fortunately most foals don't get sick, and if they do and recover, they're immune for life. In nature, most of the time,
they respond appropriately."
Dr. Kane earned his doctorate in equine nutrition and physiology from the University of Kentucky in 1978. He works within
the animal-feed industry with a specialty in horses.