Parasite Prevention

The Nitty Gritty on Parasite Prevention

Bugs. Little monsters. Disgusting worms. Itchy fleas. Gross ticks.

While it certainly could be a lot worse, parasites are real problems in the Boulder area and throughout Colorado. Nationally, over 34% of dogs are infected with some sort of intestinal parasite. To make matters worse our furry family members could be harboring parasites without showing any symptoms at all. Luckily, the vast majority of those little buggers we see in our area are easily prevented!

Keep reading to learn the nitty gritty on common parasites in the Boulder area and how to keep your furry friends (and yourself) safe from these little monsters:

Roundworm Image

Roundworms are one of the most common parasites for dogs and cats. In fact, almost all puppies and kittens are actually born with them, which is why we deworm all puppies we see here at BNAH.

Roundworms live in the stomach and intestines. Although it is possible you may not even know your pet has roundworms your pet may surprise you one day with the presence of worms in vomit or feces. If the worms make their way to the lungs they can cause significant coughing. For long term infections your pet may experience significant weight loss or have a pot-bellied appearance.

How do our pets get them? Roundworms are passed by what we call the fecal-oral route. Sounds gross huh? If a dog or cat (or human!) doesn’t eat poo then it shouldn’t be a problem, right? Well, it’s not that simple. Any animal in the wild can pass through our yards and defecate on the grass. Even after the visible feces disappears, roundwom eggs can be left behind – if our dog or cat eats that grass or licks it they can get infected. And it’s not only limited to our furry friends – these parasites are what we call “zoonotic” which means they can pass to humans. For example, if an infected dog gives us a kiss (we all know where those tongues have been!) the parasite could be passed along. Or, if we play in the yard where the parasite eggs are hiding and forget to wash our hands before eating we could contract the worm. As you can imagine, small children are particularly susceptible. A rare but dangerous disorder could occur from human exposure to the dog or cat version of roundworms – this is called Ocular Migrans. To learn more about it, click HERE.

Hookworm Image

Hookworms are tiny little parasitic worms that live in the intestines where they use their sharp teeth to attach themselves and take a bloodmeal off their host. While not as common as roundworms, hookworms do still pose a threat in our area.

Common signs that your pet is infected with hookworms are signs of blood-loss (anemia) such as weakness, fatigue, poor skin or coat condition and weight loss. Your pet may also have diarrhea. In younger or older animals this can be a very serious infection. Of course, some pets will not show any outward symptoms at all for quite some time.

Just like roundworms, hookworms are passed by the fecal-oral route. A dog or cat with a hookworm infection will pass eggs from the hookworm in their feces. Even if that feces washes away some eggs can be left behind – if they are ingested by another animal a new infection can occur. Hookworms are species specific (they only like to live in one type of animal) but they will try to infect any animal they touch. For example, if a dog with hookworm defecates on a spot of grass and several days later a human steps barefoot on the same spot of grass the hookworm larvae living there can actually penetrate the skin on that human’s foot. While it will not cause the same type of infection as in the dog it does cause a significant problem called Creeping Eruption. To learn more about Creeping Eruption click HERE.

Hookworm Image

Ticks are parasitic insects better known as ectoparasites since, unlike the worms listed above, they infect their host from the outside and live on their skin. Ticks are typically found in grassy areas where they wait to latch on to a passing animal. Once on the animals skin they attach by piercing the skin with their mouth. The mouth actually has recurved anchors which is why removal must be done appropriately to avoid risk of leaving the mouth in the skin. Once attached ticks feed off the blood of their host. To read about the proper way to remove a tick, click HERE – or stop by Boulder’s Natural Animal Hospital and one of our Veterinary Technicians will remove the tick for you!

Since ticks are ectoparasites they can be located on your pet (or you!) by feeling all over your furry friend’s skin after a walk or hike. It is always important to check your pets for ticks since the signs of a tick borne disease may not show for several days to weeks – furthermore, proper removal of a tick within 24 hours of attachment can vastly decrease the possibility of the tick transferring a disease to our animal companions.

Ticks can carry a variety of disease, the most well known of which is Lyme disease. Luckily, Lyme disease is not a big concern in the Boulder area but some other less-known tick-borne disease are. Ehrlichiosis, a subtle disease caused by ehrlichia, is found in ticks in Colorado. Symptoms of ehrlichiosis are joint pain, decreased appetite and depressions though animals infected with this tend to present with a very general appearance of just “not feeling well”.

Hookworm Image

Heartworms are parasitic worms that mature and live in the heart and blood vessels of the lungs of their host. Primarily found in dogs heartworm can also, in rare cases, infect cats. The infective stage of heartworms is carried by mosquitos – when an infected mosquito takes a bloodmeal from an animal it passes very small larvae of the heartworm into the animal’s bloodstream. Over a period of 6-18 months this microscopic stage of the worm finds its way to the animal’s heart where it slowly grows into the adult stage. An adult heartworm can be as long as 10 inches! Can you imagine a 10 inch worm living in your dog’s heart? To make matters worse, there is often more than just one worm in an infection.

One of the primary challenges with heartworm infection is that, due to the long period of time it takes the worms to mature, it can take several months to years before a pet will show any signs of heartworm infection. These signs could be weakness, fatigue, coughing and heart failure. By the time our animal companions are showing us they have heartworm the disease is highly advanced.

Since heartworm is passed by mosquitos the risk in Colorado is not as high as in other areas of the country – but the risk is not zero either and studies have shown over the past 10 years that the risk is increasing. In 2001 very few clinics in Colorado reported more than 1 or 2 cases per year – we are now seeing several clinics in the area reporting between 5-10 cases per year. We are seeing 1-2 cases each year here at BNAH.

To learn more about Heartworm, click HERE.


The good news is all of these parasites are preventable!

At Boulder’s Natural Animal Hospital we have found that a two-pronged approach to parasite prevention is key to a long, healthy life for our furry friends.

  1. TESTING – every year as part of your animal companion’s Annual (At Least!) Exam we recommend a fecal exam be performed to test for some of the worms listed here as well as some other less common parasites and bacterial infections.
    Also, depending on your current usage of prescription preventatives we recommend an annual or bi-annual heartworm test. Once again, since heartworm can be a silent disease for several months detecting it early maximizes the effectiveness of treatment and minimizes the effects on your pet.
  2. PREVENTION - for the prevention of Heartworm and the common intestinal worms listed here we recommend at least seasonal (June through November typically) usage of a monthly parasite preventative treatment called Heartgard Plus (to learn more about Heartgard Plus, click HERE). We have found Interceptor to be an extremely safe and highly effective way of preventing a variety of common parasites in our companion animals.
    Getting ourselves into the habit of regularly checking our pets for ticks, especially after walks or hikes in grassy areas, is good parasite prevention practice. For pet parents who find their pets are regularly exposed to ticks the use of a prescription topical preventative treatment might be worth considering.


Call us at 303-494-7877, email us at or schedule your furry firend’s Annual (At Least!) Exam today!