They are very similar to more common illnesses and maladies. Owners and even vets sometimes don’t pay much attention to what appears to be run of the mill problems. To make matters worse, once he starts showing signs of sickness, he’s already very very ill.

Common symptoms in the beginning are vomiting, diarrhea, breathing problems including wheezing, and coughing. They can progress to an enlarged rib cage (which grows wider to encompass the enlarged heart and lungs), bloody stools, and loss of appetite. All these symptoms are similar to those caused by more common diseases and not always recognized by owners or even vets.

They more frequently than not look like the common cold or an allergy. Even your vet may not immediately reckon of heart worm when you bring him in for a check up.

Outdoor dogs are more likely to become infected with heartworm because heartworm is transmitted by infected mosquitoes and, of course, mosquitoes are more likely to be found outside. But, since these pests can all too easily get into our homes, it’s not unheard of indoor dogs to become victims to the disease as well. And, because these same dogs don’t go out often, owners tend to ignore the symptoms and never reckon about heartworm when the coughing and wheezing starts.

Even tiny dogs can be in danger, whether they seldom go outdoors. Don’t assume that just because your small Maltese never leaves the house that his coughing or diarrhea can’t be serious. Small dogs run a higher risk of mortality, too, if heartworm is left untreated because the worms can grow to about a foot long without regard to the size of the dog or the size of his heart.

Even though prevention is the key, that doesn’t mean that your dog is immune to the disease just because he received his heartworm medication on time. Even the best medications on the market won’t guarantee that your dog will be able to ward off the effects of an infected mosquito.

One of the major reasons symptoms tend to be ignored is because the dog has received heartworm medication and there is an assumption after that that the dog must be coming down with something else; he couldn’t possibly have heartworm. This assumption can cause your dog’s demise.