So owner number 3 never tested him after his illness..... And he WAS a carrier and could have infected other horses. And indeed may have done as there was a subsequent outbreak.
I am really scared about this. My horses are now more or less immune. The pouch testing is to protect other horses. But other people are saying 'I'd rather not know' and are saying they would not bother testing at all. If mine are carriers and the flush does not work they are facing surgery or PTS. I am going ahead because I could not live with myself if one of my horses triggered another outbreak. It is bad enough that Amber triggered an outbreak that almost killed Oscar when when I DIDN'T know. So I can't imagine how I would feel if that happened when I DID know. So I can't let her or the others not be tested. But I am absolutely terrified about finding out. I would far rather not know!!
Incidentally,
@Mary Poppins the blood test looks for antibodies to strangles. It can't detect the bacteria itself. But the anti-bodies indicate that a horse has been exposed to strangles and has developed an immune response to the bacteria. The more antibodies seen, the higher the immune response and therefore the higher the bacterial load.