I had two of my dogs in recently to have their teeth cleaned and the vet highly suggested that I also have them checked for heart worms EVEN THOUGH they are on Sentinel preventative year round. Apparently many dogs are showing up with heart worms and they don't know if it's a problem with the drugs or if the mosquitoes that carry the disease have mutated so the drug is not as effective.
Last year I commented to the vet that I was seeing ticks that were alive and fat on the dogs occasionally and that before they were either dead or nearly dead when ever I found one. He said Sentinel isn't for ticks and I told him that I knew it didn't say it was for ticks but, I had never had this happen before. I'm wondering if that is when the drug failure started. I like Sentinel because it makes fleas so they can't reproduce and works for various other worms besides heart worm.
I know should have put this under pets but, I sometimes don't get down that far and I wanted to be sure all would see the information.