The day before yesterday my dog Levi started coughing, and had an accident in the house. Then yesterday he would not eat or drink, and was having trouble standing. We took him to the vet and they said he had a virus along with the heartworms he had when we rescued him 2 years ago. The heartworms, and heartworm medicine had weakend his immune system so the virus took over. He passed away this morning and my heart is broken. Make sure you keep your furbabies on heartworm preventative!