I put a flea and tick collar on my dog and a week later he started panting a lot. At first I assumed it was just because he was hot. After a few days I took him to the vet. The vet said it could be pneumonia, blastomycosis or lung cancer. He ran some tests but I removed the collar that night just because I didn’t think he needed it if we weren’t out at camp. The vet ruled out pneumonia and blastomycosis, so he said it had to be lung cancer. Within a few days of removing the collar his breathing was better. If he would have had lung cancer he would have gotten worse not better. Therefore I believe it was the flea and tick collar.