Any dog you adopt can get heartworm if they aren't kept on preventive medications (Interceptor is one). Keep her on monthly meds and have her tested once a year just like any other dog.

Once heartworm treatment is complete, the current infection is cured. There may be some permanent heart and/or lung damage. Any dog not on heartworm prevention can become infected with heartworms, including those who have been infected before.

It's been about a year ago, but somebody posted a thread about a dog who tested negative she got at a shelter, and had been on preventative and retested and was found positive. I can't remember the context of it, but it was an extenuating circumstance and does anybody remember the meat of it?

I had a dog years ago who tested positive. He was a pound dog (not even shelter) and I was ignorant of it or preventatives at the time, so he had to be treated with arsenic. It was scary and also expensive. He survived, but some don't. I would not be afraid to adopt a dog who had been treated successfully as far as recurrence.

Dog has to be infected with heartworms for 6 months before test becomes positive. Once a non-protected dog is bitten by an infected mosquito, it takes 6 months for the immature larval stages to mature and migrate to the heart and start producing antigens that our test detects. If a dog got infected less than 6 months ago, the test will be negative and you won't know it had been infected until the next heartworm test.

Thank you all; I ended up adapting a different dog from the shelter. I have to take him now for neutering

Thank you meghane. Best wishes on your new buddy, Sethramesh.