salmonella in horses

well, i need some info on salmonella in horses. I searched on the interent about it but i wanted to know if anybody had any actual experience with it. A horse at the barn that i board my horses at has a displaced collon and salmonella poisnoning and ofcourse my horses are in the pasture beside him. I need to know how contagious it is and what i need to do if it is extremely deadly. I don't have any other place to isolate the horses if they do have it so i'm kinda stressing out. Another lady at my barn called our vet and he said it is not contangious unless the other horses are actually directly in the same pen but i am still worried. Has anyone dealth with salmonella in horses? Any advice of what to look for would be great!