If you are a dog, you will want to watch out for heartworms and not get them because they are horrible, nasty things that can KILL YOU! And the way you get them is that a mosquito bites you. But it's not just any mosquito. It has to be a mosquito that has these teeny, tiny heartworm larvae things. And then the larvae get into your blood and they swim around all through you, but mostly they like to hang out in the lungs and the heart. And then the larvae grow up and become adult worms, and they mate and have baby worms, and all the worms grow up and live in a part of the heart that is called the right ventricle. They look kind of like spaghetti, and they can get to be as long as 12 or 14 inches. Which is why if you get enough of these worms living inside you, you can get very, very sick.
The fancy, scientific name for heartworms is
Dirofilaria immitis. Dogs are the most usual host of the heartworm, but wolves, coyotes, foxes, cats, ferrets, and sea lions can also get them. Sometimes even a human can get heartworms, but they don't live long inside a human, so it's not a big deal like it is when a dog gets heartworms.
People started finding heartworms in dogs back in 1847 and in cats in the 1920s. At first, heartworms were mostly in the south part of the U.S., but now they are in all the states except Alaska, and also in southern Canada. Here's a map that shows where the most heartworms are in the U.S. You can also find them in South America, southern Europe, Southeast Asia, the Middle East, Australia, and Japan. So as you can see, those heartworms really get around!
If you get infected with heartworms, it might take several years before you start having symptoms, and by the time you have symptoms, you are probably already very sick. All those worms in your heart and lungs will make you have a cough, and you'll get tired easily and won't feel like going for walks. You might get heart failure, which can make your tummy get all kind of swollen looking because there's a bunch of fluid in there. Here's a picture of a dog that has heart failure because of heartworms.
But the good news is that you don't need to wait until you have nasty symptoms to find out if you have heartworms. You can just get a blood test, and then your vet will tell you if you have them or not. If you do have them, you can get a treatment that will kill the heartworms, but it is not a fun treatment, and also it is expensive. And the most usual kind of treatment is this stuff called Immiticide. It's got arsenic in it, which is poisonous, and that's how it kills the worms. And the vet has to shave two places on your back, near your tail, and they inject the poison there. Mom saw a dog at the shelter getting this treatment, and it looked very painful.
Anyway, after you get the treatment, you have to be quiet and rest for several weeks, which is a real bore. And the reason for this is so that your body can absorb all the dead worms. Otherwise, if you run around, the dead worms might get in your lungs and cause you to not be able to breathe, and this could kill you!
But the even better news is that you can keep from getting heartworms in the first place by just asking your mom or dad to give you what's called a heartworm preventive. At our house, we get Heartgard, and Mom just puts it in our supper once a month, and we gobble it up with our food because it's very yummy. And what it does is if we have been infected in the past month with any heartworm larvae, the preventive will kill them. We get Heartgard every month, all year round, even though the mosquitoes don't usually bite in the winter. But Mom wants to keep us safe, which is one thing that makes her a good mom!
