Intestinal Parasite Screening for Dogs and Cats: What to Expect

Why Intestinal Parasite Screening Matters

Because intestinal parasites are common, often invisible at first, and easy to find with a simple test. Many dogs and cats carry parasites without obvious symptoms, and some of those parasites can infect people. A fecal test is the most direct way to know what is going on in your pet's gut.

"Intestinal parasite screening is an important part of your pet's routine wellness lab work," Dr. Long said. "It's a really easy and noninvasive way to find out if there are parasites in their intestines that could be causing disease."

What parasites do to your pet. Intestinal parasites live in the gut and feed on your pet's blood or the nutrients passing through. "Intestinal parasites can cause things like vomiting, diarrhea, and even anemia," Dr. Long explains. In puppies and kittens, a heavy worm burden can stunt growth, and blood loss from hookworms can become dangerous quickly. Adult pets often tolerate a low-level infection with few signs, which is why screening is part of routine care rather than something saved for sick visits. It sits alongside blood work and a urinalysis in a full wellness panel, which our post on routine screening lab work covers in detail.

Why it matters for your family. "Importantly, there are some types of intestinal parasites that can be passed on to people, especially young children and older people, but also immunocompromised people," Dr. Long said. Roundworm eggs and hookworm larvae in contaminated soil or sand can infect people, and children who play outside are at the highest risk. "So routine fecal testing is a really important part of not only your pet's health, but also your family's health," she added. Keeping your pet's screening current is one of the simplest ways to protect everyone in the house.

What intestinal parasites do dogs and cats get?

Roundworms, hookworms, whipworms, tapeworms, Giardia, and coccidia are the parasites most often found in dogs and cats. Some are worms you might eventually see; others are single-celled organisms you never will without a microscope.

Roundworms. The most common intestinal worm in puppies and kittens, often passed from mother to offspring before birth or through nursing. Adult pets pick them up from contaminated soil or by eating infected rodents. Roundworm eggs can survive in the environment for years, and they are the parasite most often passed to children.

Hookworms. Small worms that attach to the intestinal wall and feed on blood. They are a leading cause of anemia in young animals. Pets are infected by swallowing larvae or through larvae penetrating the paws, and the larvae can also burrow into human skin.

Whipworms. More common in dogs than cats. They live in the large intestine and cause chronic diarrhea, sometimes with blood or mucus, and weight loss.

Tapeworms. Usually acquired by swallowing an infected flea while grooming, or by hunting rodents. Owners often notice tapeworms first, as rice-grain-sized segments around the tail or in the stool. Tapeworm eggs frequently do not show up on a standard fecal test, so if you see segments, tell your vet.

Giardia and coccidia. Single-celled parasites rather than worms. Giardia spreads through contaminated water, soil, and surfaces and causes soft, greasy, foul-smelling stool. Coccidia is especially common in puppies and kittens from crowded environments. Both can be found on a fecal test, and Giardia is often confirmed with an antigen test on the same sample.

What are the signs of intestinal parasites in pets?

Diarrhea, vomiting, and a decreased appetite are the most common signs, and many pets show no signs at all in the early stages. That is why a fecal test is run routinely and not only when a pet looks unwell.

"It's very easy for pets to get exposed to intestinal parasites if they spend much time outside or around other pets," Dr. Long said. "If your pet has signs of intestinal disease such as vomiting, diarrhea, or sometimes a decreased appetite, your veterinarian will often recommend a fecal test to look for parasites because they are such a common cause of those symptoms in dogs and cats."

Signs to watch for. Along with digestive upset, look for weight loss despite a normal appetite, a dull or rough coat, scooting or licking around the rear, a bloated belly (particularly in puppies and kittens), pale gums that can signal anemia, and visible worms or segments in stool or vomit. In cats, a slightly thinner body or a less glossy coat may be the only hint.

Why healthy-looking pets still need testing. Many adult pets carry a small parasite load without ever looking sick, and they shed eggs into the yard, the litter box, and the house the entire time. Screening finds those silent infections before they build up or spread. If your pet is showing signs now, book an appointment so the fecal test can be run promptly. If you are unsure whether a bout of loose stool warrants a visit, Modern Animal All Access and Essential members can reach our team anytime through 24/7 Virtual Care.

How do I collect a fecal sample?

Pick up a small amount of fresh stool, seal it in a bag or container, and bring it to your appointment. It takes about a minute, and you need far less than most people expect.

"You might be asking yourself, how do I collect a fecal sample?" Dr. Long said. "Literally pick it up off the ground using the bag that you have on your dog's leash and bring it in in the bag. You can also do the same thing with your cat in the litter box."

How much to bring. Not much. "The amount of basically the end of the pinky finger to the first joint is enough to test for parasites," she explains. A full bag is not necessary, and a clean, sealed container of any kind is fine.

Freshness and storage. A sample from the past day is ideal, since parasites and eggs break down over time and an old, dried-out sample is harder to read. If you collect it the night before, seal it and keep it cool.

If you cannot collect one. "Either you bring it in when you come, or we can obtain a sample here in the office," Dr. Long said. There is no need to reschedule if your pet does not cooperate beforehand.

What the lab does with it. The most common method is fecal flotation, in which the sample is mixed with a solution that makes parasite eggs float to the top so they can be identified under a microscope. Many clinics also run an antigen test on the same sample, which detects proteins from parasites such as Giardia, roundworms, and hookworms even when eggs are not being shed at that moment.

When is a fecal test recommended?

At least once a year for adult dogs and cats, several times during the first months of life for puppies and kittens, and any time a pet has digestive symptoms. Pets with higher exposure may benefit from testing more often.

Puppies and kittens. Young animals are the most likely to carry parasites and the most vulnerable to them. They are typically tested at their early wellness visits during the vaccine series, and many are treated for roundworms and hookworms preventively because infection from the mother is so common.

Adult pets. A fecal test is a standard part of the yearly wellness visit for healthy adults, and it pairs naturally with the rest of the annual wellness exam. Some vets recommend twice a year for pets with regular exposure.

Higher-risk pets. Dogs that visit dog parks, daycare, boarding, or trails, cats that go outside or hunt, pets in multi-pet households, and newly adopted animals from shelters or rescues are all more likely to pick up parasites. A fecal test is also a good first step for any new pet joining the household.

When symptoms appear. As Dr. Long noted, vomiting, diarrhea, or a drop in appetite will often prompt a fecal test regardless of when the last one was run, because parasites are one of the most common and most treatable causes of those signs.

After treatment. If parasites were found and treated, your vet will usually recommend a recheck a few weeks later to confirm the infection has cleared, since some parasites need more than one round of medication.

What happens after the intestinal parasite test?

Results typically come back within a day or two. If the sample is clear, you will know right away. If parasites are found, your vet will tell you what was detected and how to treat it, and treatment usually starts the same day.

"It's very simple. When we get the results, we'll notify you in the app and let you know if your pet's fecal sample came back with no sign of parasites, or if there are parasites," Dr. Long said. "We'll tell you how we're going to treat those, and you can come pick up the medication and start right away."

Treatment. Most intestinal parasites are treated with an oral dewormer, given once or over a few days depending on the parasite. Giardia and coccidia need different medications than worms, which is one reason identifying the specific parasite matters. Your vet will also tell you whether other pets in the home should be treated, since parasites spread easily between animals sharing a yard or litter box. If questions come up after you see the results, Modern Animal All Access and Essential members can reach our team anytime through 24/7 Virtual Care.

Preventing reinfection. Treatment clears the parasites your pet has now; prevention keeps them from coming back. Many monthly heartworm preventives also protect against roundworms and hookworms, and some broad-spectrum products cover fleas and ticks as well, which matters for tapeworms. Our post on heartworm testing and prevention explains how those products work together. Modern Animal members can set up Autoship for monthly preventives through the app so doses arrive on schedule, and pricing for preventives is listed in the app's pharmacy hub.

Cleaning up the environment. Pick up your dog's stool promptly, especially in the yard, since roundworm and hookworm eggs become infective after sitting for days and can persist in soil for a long time. Scoop litter boxes daily. Wash hands after handling stool or litter, and keep children's play areas and sandboxes covered or clear of pet waste. Keep up with flea control to break the tapeworm cycle.

What does a fecal test cost?

Fecal testing costs vary depending on where you live. The test itself is typically run as part of a broader wellness visit, which can affect the overall price depending on what else is recommended at that appointment.

What affects the price. The type of visit is one factor, since a fecal test run during a wellness exam is billed alongside that exam, while a test run at a sick visit or on its own is structured differently. Your pet's age and health history can shape what else your vet recommends at the same appointment, and if additional diagnostics such as an antigen test or blood work are suggested, those are priced separately.

For a full breakdown of service and test pricing at Modern Animal, visit modernanimal.com/pricing. Everything is listed transparently so you know what to expect before you come in.

The bottom line. Intestinal parasite screening is one of the easiest things to stay on top of and one of the most worthwhile. A pinky-tip-sized sample, a quick test, and a clear result go a long way toward keeping your pet comfortable and your household safe, and most parasites that turn up are simple to treat once they are identified. Test at least once a year, more often for young pets and those with a lot of outdoor or animal contact, and any time digestive symptoms show up.

If your pet is due for a wellness visit or you want to get a fecal test on the calendar, book an appointment and we will take care of the rest. For more on preventive care, visit the Modern Animal blog.