I have a horse that had Strangles about 6 years ago. He has been checked by the vet and had blood work done but not the Strangles test. Has anyone had a situation like this? He has a white discharge from his nostrils and swollen throat latch. There are other horses in the pasture with him, one has never had Strangles so I'm wondering if he is a carrier or if this is something else.