First thing is make sure you don't get infected. What does your vet say you can do? I looked this up in my old (outdated) vet manual. According to it,you would not want to keep the cow because she is a carrier. Not sure how you'd handle that. It lists five sources for infection. Recovered cows, Infected calves, pigs poultry and humans, rats and infected buildings and trailers. I know it's fairly common in hogs and chickens and they can spread it. Cats, birds and nasty water can too. Hopefully,somebody has more up to date, better information. I'd be pumping your vet for more information. He should be your best source, since he's there and can see what you've got to deal with. You might try searching the archives here too. Go to the top of the page, click on the search tab, and enter salmonella in the box. It'll bring up every post on this board that mentions salmonella. Good Luck to you. Hope you come out OK.