By Lisa Feinstein, DVM MPH


Veterinarians recommend monthly heartworm prevention and flea/tick prevention. You may ask “Why?” since we don’t take these and we don’t have them and our dogs and cats are living with us in our houses. Well, that’s even more of a reason your pets should be taking monthly heartworm prevention. Our pets are in our houses, sleeping with us in our beds, giving us kisses, and sometimes even sharing food off our plates. And the odds are that 25% to up to 50% of our dogs in the Southeast have parasites. A recent study (Blagburn 2007) showed 52% of shelter dogs carry parasites, with hookworms, roundworms and whipworms being the most common. Percentages are lower for owned pets, but they still are around 12% nationally and higher for the Southeast (

You may say “Yuck”, then “How does my pet get these worms?” Well, the term Fecal-Oral means poop to mouth and that’s what’s happening. Essentially your dog (or cat) is ingesting micro amounts of feces that have the parasites in it. The infected poop from one dog gets into your dog or cat’s mouth when he licks another dog’s rear end or when he licks his paws that are dirty after playing at the dog park. Another route of infection is through mother to puppy or kitten. And these parasites get into your dog and then get shed through your dog’s feces, making it possible for you, your family or your other pets to get infected. Fecal worms suck blood and cause intestinal inflammation, diarrhea and disease. Heartworms create lung and major heart vessel damage that can be fatal over time. If you get exposed to these parasites, they can create rashes on your body (cutaneous larva from hookworms) and migrant larvae can spread into your organs (visceral larvae from roundworms). Kids are easy targets since they don’t often wash their hands before eating and put their hands in their mouths.

So how do you prevent this? If your dog or cat goes outside at all, there is an opportunity for fecal exposure. Even indoor pets, that eliminate in litter boxes or on wee-wee pads, can get exposed to heartworms, since they are blood-born parasites transmitted by mosquitoes. We have all seen mosquitoes in our houses. Let’s face it. There’s no real way to prevent parasites from trying to get our pets. So what do we do? We fight back by going after them. Every month giving your dog or cat a heartworm prevention tablet like Heartgard or Interceptor or a topical like Revolution will kill the worms the pet was exposed to the previous month, not allowing them to take up residence in your pet. The heartworm prevention kills both fecal worms like hookworms and roundworms, and heartworms.

Fleas and ticks are external parasites and they are also out there, waiting to find a host to attach themselves to. They can quickly multiply when they can feed off your pet’s blood, and soon you can have an infestation. By being proactive and applying flea and tick prevention (like Bravecto or Revolution) and heartworm prevention, you prevent a parasite from taking up residence. Your pet and you will be healthier. Remember that ticks, fleas and worms can also infect you!