Parasites can cause a number of illnesses, conditions and diseases that can cause uncomfortable symptoms and, in some cases, serious complications. Our East Setauket vets share some of the most common pests and discuss why parasite prevention and control are important for your dog's health.

Why is parasite prevention important for dogs?

Parasites can live externally or internally on your dog. These parasites live strictly off the blood and vital nutrients their blood provides.

Some cause irreversible, severe damage to your dog's organs. Many dog parasites include hookworms, heartworms, tapeworms, lice, ticks, and fleas. 

In this post, we'll examine some common parasites, explain why your dog needs parasite prevention, and how your vet can help.

How do parasites infect dogs?

Infection usually does not occur through direct contact. However, there are many indirect ways these pests can be passed on. Parasites contracted through animal feces can be passed down from mother to child before birth, and they can also be transmitted through the bite of an infected insect.

External Parasites

External parasites live on the skin of your dog. The two common external parasites are fleas and ticks.


Fleas are an external parasite that depends upon a host animal for survival, in this case, your dog. Once these tiny parasites have made themselves home on your pet, they will multiply astonishingly. Some estimates calculate that for every adult flea you find on your pet. There may be 100 or more immature fleas hiding throughout their coat. Also, if your pet has fleas, there is a good chance that these parasites invade your home, hiding in carpets and soft furnishings.

Many dogs are allergic to the proteins left behind when fleas bite, which causes the bite area to become intolerably itchy. When this happens, pets often scratch and groom excessively, leading to raw, damaged patches of skin, fur loss, and, in some cases, infections. Additionally, there is an additional danger that infected fleas can transmit tapeworms to your pet.


Ticks are external parasites that rely on 'hosts' for transportation and food. A host is a person or animal the tick lands on and begins feeding on. Ticks feed on the blood of their hosts, including humans and animals.

This parasite is common worldwide; many species are found across North America. Each type of tick comes with serious risks to pet and human health. Tick saliva contains a variety of germs and bacteria that can be transmitted to the animals and people they prey on. These bacteria can lead the host to develop conditions such as Rocky Mountain spotted fever, Canine Bartonellosis, Anaplasmosis, Ehrlichiosis, alpha-gal syndrome, or Lyme disease.

Internal Parasites

Internal parasites live within your dog's body, usually in the gastrointestinal system. The three most common internal parasites are roundworms, tapeworms and heartworms.


Roundworms are a common parasite in pets. As the name implies, large roundworms live in the intestines and cause ascariasis. Kittens and puppies generally become infected with roundworms through nursing and can catch contact with this parasite by eating the larvae found in the feces of other infected animals. Roundworms are a zoonotic parasite, which means humans can also become infected with roundworms.

If your pet has roundworms, you may notice symptoms such as diarrhea, lack of energy, weight loss, or vomiting. There may be no signs of infection in pets with few worms, but you may see them in your dog's stool or vomit. Since roundworm infection symptoms aren't always easy to spot, it is essential to have your pet attend routine wellness exams at your vet's office and have yearly fecal exams.


These are flat, long, segmented parasites that attach to the walls of the small intestine. The Dipylidium canine species most commonly infect dogs, but several types are known to infect pets. Most pets get infected by swallowing a flea infected with the tapeworm, which can quickly happen while grooming or responding to flea bites.


Heartworms, or Dirofilaria immitis, are protozoan parasites that live in dogs' hearts, lungs, and surrounding blood vessels. Infected mosquito bites transmit this disease; when eggs enter your pet, the larvae travel through the bloodstream for several months, finally settling in the heart and pulmonary arteries.

Heartworm infections go undetected for months until the condition reaches more advanced stages when damage to the pet's internal organs has already begun. Treatment for heartworm disease is available; however, it is toxic to the pet and can be very expensive. For this reason, many pet parents find themselves having to make the heartbreaking decision to euthanize cherished pets diagnosed with heartworm disease.

How to Prevent Parasites in Dogs

Naturally, after discovering how many parasites our dogs can contract and their potential health effects, pet owners' next question is, 'How are parasites prevented?'.

Routine vaccinations are the best way to prevent several illnesses caused by parasites. Your vet will be able to advise you of a schedule for inoculation. Make sure your dog goes for an annual wellness check so your vet can test for infestation.

Several parasite prevention products are on the market to help deter the parasites from calling your dog home.

How Your Vet Can Help Protect Your Dog

Parasites can pose a significant danger to even the healthiest dog. That's why parasite control for dogs, including various parasite prevention practices and products, is vital to protect your pooch and your family. 

Along with routine wellness exams, parasite prevention is vital to ongoing healthcare. During your pet's annual exam, your veterinarian in East Setauket can check your dog for any signs of parasites and recommend parasite control measures or products that would be suitable for them based on your location, your dog's risk factors, health status and more.

We are also happy to address any questions and concerns about parasite prevention and control. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Is your dog due for routine parasite prevention? Contact our East Setauket vets today to book an appointment.