campylobacteriosis and clostridial enterotoxicosis

How deathly are these, and how contagious? I have heard it lives in soil and if a dog gets it you can't get rid of it. One dog has tested positive for these things. Vet says just quarantine. But now my other dog is sick. And I don't know how to disinfect my yard from the diarrhea... Don't want to spread or re-infect. Any advice...I'm scared...and really freaking out.

Hello - this is a huge question so Im going to answer it in small chunks throughout the day.  Ill tell you when Ive finished.    

Hello - I think the first thing to say is, well done for spotting your overwhelm and stress and reaching out to try to control the situation.   Campylobacter and clostridia are two different infections caused by two different bacteria, both of which are associated with diarrhoea and can have consequences ranging from negligible to slight diarrhoea to a systemic infection (enterotoxicosis).  Diarrhoea can also be caused by a range of other things.  So, out of context it is difficult to advise you.  Where a dog has diarrhoea, they may be dehydrated and need iv fluids to replace that being lost.  More to follow

Your vet should therefore assess dogs with vomitting and / or diarrhoea regularly in case this is needed, especially if they appear lethargic.  Antibiotics may be needed in some individuals and preventing a build-up of pathogens in the environment (good environmental hygeine) is important, as well as good personal hygeine for any humans involved.  Please do ask direct questions of your vet regarding 'good hygeine' and prognosis, as they should  know your set-up and can give appropriate information and instructions to your situation and surroundings.  The more your vet understands about your circumstances and home environment, the better they can help.   I hope that something there is useful.