Well, when your dog first gets heartworms you can never tell, the dog can, but you can't. Eventually the heartworms will get to a stage where they cause the dog to cough. The small cough every now and then will turn into a cough often, soon, the dog will have productive coughs... The heartworms will then reach the heart, lungs, etc. causing your dog to live in pain and eventually death. That's why you get your dog checked for heartworms every 6 months to a year. You give your dog heartworm preventives monthly only if your dog is free from heartworms.
Humans do not get heartworms, but they can get ringworms, hookworms, etc. You would be able to tell immediately if you had them, after you got them, but it is rare for humans to get them, even though it does happen.
Those worms are parasites and are much easier and less expensive to treat then heartworms.
My dog also had hookworms, but we gave her a panacure and she was free of them with in a month. It cost about 50 dollars to treat parasites, and about 900 - 1200 or so to treat heartworms depending on the stage of the heartworms.
See the difference?
It cost me almost 900 dollars to treat Joy for heartworms. She was at the beginning stage of class two...
Oh yeah!! Joy is now finished with her treatment and will be checked in Sept for heartworms. Sept will give the heartworms plenty of time to weaken and die. Today she can be hyper as we have had to keep her calm through the treatment process. Until we will just give her heartgard!
"Dogs are not our whole life, but they make our lives whole." ~ Roger Caras