How to Tell If Your Pet Has Worms: Signs, Treatment and Prevention

By Dr Duncan Houston

Quick Answer

Pets with worms may show signs such as diarrhea, weight loss, a bloated abdomen, scooting, or visible worms in stool, but many infected animals show no obvious symptoms. Regular parasite prevention and testing are essential to protect both your pet and your household.

As a veterinarian, I often diagnose intestinal parasites in pets that appear completely normal at home, which is why routine prevention and screening are just as important as treating obvious infections.

Worms are far more common than most pet owners realise, and they are not always easy to spot.

Some pets will show clear signs, while others carry parasites quietly in the background. Left untreated, these parasites can affect digestion, growth, energy levels, and overall health, especially in young or vulnerable animals.

Common Types of Worms in Dogs and Cats

Roundworms

Roundworms are one of the most common parasites, especially in puppies and kittens.

They may appear:

• Long and spaghetti-like

• Visible in vomit or stool

They are often passed from mother to offspring early in life.

Tapeworms

Tapeworms are flat, segmented parasites.

Signs include:

• Small segments that look like grains of rice

• Found around the anus, in bedding, or in stool

They are commonly transmitted through fleas.

Hookworms

Hookworms are small but can cause significant problems.

They:

• Feed on blood in the intestine

• Can lead to anemia

• Often cause diarrhea or dark stools

They are rarely visible to the naked eye.

Whipworms (Dogs)

Whipworms affect dogs and can be difficult to detect.

They may cause:

• Chronic diarrhea

• Weight loss

• Blood or mucus in stool

Diagnosis often requires specific fecal testing.

Protozoal Infections (Not True Worms)

Organisms such as Giardia and Coccidia are not worms but behave similarly in the gut.

They can cause:

• Soft stool or diarrhea

• Poor growth in young animals

• Intermittent digestive upset

Signs Your Pet May Have Worms

Some pets show obvious signs, while others show very little.

Watch for:

• Visible worms or segments in stool or around the anus

• Diarrhea or soft stools

• Weight loss despite normal eating

• Pot-bellied appearance in young animals

• Scooting or excessive licking of the rear

• Vomiting

• Poor coat quality

• Lethargy

In some cases, coughing can occur if parasites migrate through the lungs.

Why You Might Not See Any Signs

One of the biggest challenges with parasites is that many pets appear completely normal.

This means:

• A healthy-looking pet can still carry worms

• Signs may only appear once the burden is high

• Routine prevention is critical

Waiting for symptoms is not a reliable strategy.

How Vets Diagnose Worms

Diagnosis is usually straightforward but requires proper testing.

Fecal Examination

A stool sample is examined under the microscope to detect eggs or larvae.

Advanced Testing

More detailed testing may be used for harder-to-detect parasites or chronic cases.

Visual Identification

In some cases, worms or segments are visible without testing, particularly with roundworms or tapeworms.

How Worms Are Treated

Treatment depends on the type of parasite.

Most cases are managed with:

• Prescription deworming medications

• Targeted parasite treatments

• Repeat dosing schedules

• Follow-up testing where needed

Different parasites require different medications, which is why accurate diagnosis matters.

Preventing Reinfection at Home

Treating worms is only part of the solution. Preventing reinfection is just as important.

Hygiene Measures

• Pick up faeces promptly

• Clean litter trays regularly

• Wash bedding frequently

Environmental Control

• Reduce exposure to contaminated soil or faeces

• Prevent hunting of rodents or wildlife

• Control fleas consistently

Ongoing Prevention

Prevention is much easier than repeated treatment.

Puppies and Kittens

• Regular deworming from a young age

• Typically every 2 weeks early on

Adult Pets

• Routine parasite prevention based on lifestyle

• Regular fecal checks as recommended

The exact schedule depends on your pet’s risk factors, environment, and exposure.

Can Humans Catch Worms from Pets?

Some parasites can be transmitted to humans.

These include:

• Roundworms

• Hookworms

• Giardia

Risk is higher in:

• Children

• Immunocompromised individuals

• Environments with poor hygiene

Simple precautions go a long way.

Reduce Risk By:

• Washing hands after handling pets or waste

• Cleaning up faeces promptly

• Preventing pets from contaminating play areas

When to See a Vet

You should seek veterinary advice if:

• You notice worms or segments

• Your pet has diarrhea or weight loss

• Your pet is young, elderly, or unwell

• Symptoms persist despite treatment

• You are unsure what parasite may be present

Even without symptoms, routine checks are important.

Final Thoughts

Worms are common, often invisible, and easy to overlook.

The key is not just treating them when you see them, but preventing them before they become a problem. With the right approach, most parasite infections are simple to manage and avoid.

FAQs

Can indoor cats get worms?
Yes. Indoor cats can still be exposed through fleas, contaminated food, or dirt brought into the home.

Are over-the-counter dewormers effective?
Some may work, but many are outdated or not targeted to the specific parasite. Vet-recommended treatments are more reliable.

How often should I deworm my pet?
This depends on age and lifestyle. Young animals need frequent treatment, while adults require ongoing prevention tailored to their risk.

Tracking parasite treatments, stool changes, and prevention schedules can make a big difference over time. The ASK A VET™ app can help you keep everything organised and spot patterns early.