Six months of age. We could put them on prevention much earlier before that, but the time to test them to see if they have adult worms - at the earliest - would be at six months.

So there have been studies and some of these studies have shown that even 25% of pets that are indoors can get heartworm. You might ask, “How how can my dog get heartworm if they’re only indoors? The same way that we get mosquito bites and we're indoors; a mosquito can fly inside and bite your pet or feed from your pet. Som yes, even indoor pets can get heartworm or you take your indoor dog for a walk or they go out for potty. So there are cases in which indoor dogs do tend to get heartworm as well, so they also need to be on prevention.

Yes, heartworm prevention is necessary. They've detected heartworm in every state in the U.S. and it is of growing concern because people in states that didn't have it before but now are having it didn't have their pets on prevention. So for example, I live in an area where we do get coyotes—coyotes can transmit it because it's transmitted from mosquitoes, so if a mosquito bites a coyote and then bites your dog, they can get it. So it is represented in all 50 States so, yes, all dogs need to be protected.

They’re not visible. It's not like any worms that you could see in the poop or the stool, sometimes when dogs do have internal intestinal parasites, as this is one that lives in the bloodstream. The only way to really visualize them is with the use of imaging like x-rays or ultrasound. So they're not visible on just examination, you need other special tools to help you take a look at them.

It’s hard to say in pets whether it is painful. I don't think the worm as it travels itself is necessarily painful, but as they develop these symptoms, discomfort and pain follows. The inflammation that the worm causes can lead to pain as well inside the body.