Silly Shepherds · Approx. 9-minute read
Sometimes you can see fleas. Usually, you can’t see worms. And that second part is where things often go wrong: a dog who looks perfectly healthy can still have a worm infection.
This is the second article in our series about parasites in German Shepherds. Last time, we covered ticks. Now it’s fleas and worms: what they do, what you can check yourself, and when you need your vet.
We’re not veterinarians. This article helps you recognize risks and warning signs, but it doesn’t replace advice for your individual dog. Ask your vet which products and prevention schedule suit your dog and where you live.
Fleas: the problem isn’t just on your dog
A flea is tiny. The trouble it causes can be anything but.
For a dog with flea allergy dermatitis, even a few bites can trigger intense itching, scabs, bald patches, and damaged skin. Fleas can also transmit a common tapeworm when a dog swallows an infected flea while licking or chewing.
Why an infestation is so hard to get rid of
The adult fleas on your dog are only part of the problem.
Eggs, larvae, and pupae can be scattered throughout your home: bedding, carpets, furniture, the car, and gaps along baseboards. The pupal stage is particularly well protected. New adult fleas can emerge long after you start treating the dog.
That helps explain the unwelcome surprise some people find after a vacation: they walk back into the house, and suddenly there are fleas everywhere.
Treating the dog alone may leave the rest of the infestation untouched.
How to check for fleas
Watch for frequent scratching and chewing, especially around the hips, base of the tail, and belly. Look for irritated skin, scabs, and thinning hair.
Use a flea comb over a light-colored towel or sheet. You may find a flea, but you’re more likely to find flea dirt: tiny black or dark brown specks.
Place those specks on damp white paper towel. A reddish-brown stain suggests digested blood from flea droppings.
Finding nothing doesn’t completely rule out fleas, especially in a dog with a flea allergy.
What to do if you find fleas
Treat your dog with an appropriate product and address the other pets in the household at the same time. Each animal needs a product suitable for its species, age, weight, and health.
Then tackle the environment:
- Wash pet bedding and blankets at the highest temperature the fabric allows.
- Vacuum floors, baseboards, furniture, and the car thoroughly.
- Dispose of the vacuum bag or empty the container into a sealed bag outside.
- Follow your vet’s advice about any additional environmental treatment.
Keep treatment going for the recommended period. A week without seeing a flea doesn’t mean every developing flea has disappeared.
Fleas can survive indoors during colder months. In the United States, CAPC recommends year-round flea control; elsewhere, your vet can advise on the appropriate schedule for local conditions. Fleas
Choosing products: cats and German Shepherds
Never use a dog product on a cat
Some flea products intended for dogs contain permethrin, which can cause severe poisoning in cats.
Exposure can also happen when a cat comes into contact with a recently treated dog. Tell your vet if you have cats, and follow the product instructions about keeping animals apart after treatment.
Always check the species, weight range, minimum age, and directions on the label. Don’t combine products without professional advice. FDA
German Shepherds and the MDR1 mutation
The inherited MDR1, or ABCB1, mutation has been identified in German Shepherds. Dogs with this mutation can be unusually sensitive to certain medications.
That does not mean every flea or worm product is dangerous for every German Shepherd.
The risk depends on the medication, dose, and individual dog. A DNA test can establish whether your dog carries the mutation. If you have concerns, ask your vet about testing and product selection. Washington State University
What about home remedies?
Garlic, brewer’s yeast, coconut oil, and essential oils shouldn’t replace proven flea prevention.
“Natural” doesn’t automatically mean effective or safe. Garlic and some essential oils can be toxic to pets.
Choose a product with established effectiveness and clear instructions, with help from your vet when needed.
Worms: often there without obvious signs
Many dogs with worms show few or no signs at first.
That doesn’t make an infection harmless. Some parasites can make your dog seriously ill, and some also pose a risk to people.
Roundworms
Puppies can acquire roundworms from their mother before birth or through nursing.
Possible signs include a potbelly, poor growth, a dull coat, vomiting, and diarrhea. Adult dogs may look healthy while still passing parasite eggs in their stool.
Those eggs can persist in the environment and pose a risk to people, particularly children.
Ask the breeder or rescue which treatments your puppy has already received, and follow your vet’s puppy deworming and testing schedule. Puppies need a different plan from adult dogs. Ascarid
Tapeworms
Tapeworms are flat, segmented worms. You may notice segments resembling grains of rice around your dog’s rear end, on bedding, or in the stool.
Depending on the species, dogs can become infected by swallowing infected fleas, eating prey, or consuming infected raw meat or organs.
Not every dewormer treats tapeworms.
If your dog has flea-associated tapeworms, both the tapeworm infection and the fleas need attention.
Fox tapeworm: a risk that depends on location
We live and walk our dogs in South Limburg, in the Netherlands. Fox tapeworm, Echinococcus multilocularis, is a local concern here.
Dogs can develop an intestinal infection after eating infected rodents, often without obvious symptoms. People can become infected by accidentally swallowing parasite eggs from contaminated material. Human illness is uncommon, but it can be serious and may take years to become apparent.
You can’t identify these tiny worms or their eggs by casually looking at your dog’s stool. RIVM
For international readers, the important point is to ask about local Echinococcus risks, especially if your dog hunts, eats rodents, or consumes raw organs.
The species involved and the prevention plan vary by region. Your vet may recommend a specific tapeworm treatment, often containing praziquantel, on a regular schedule for dogs with significant exposure.
Lungworms
There are different lungworm species, and their distribution and transmission routes vary.
One important example in the UK and parts of Europe is Angiostrongylus vasorum, which dogs can acquire by swallowing infected slugs or snails.
Possible signs include coughing, tiring easily, breathing difficulties, lethargy, and sometimes bruising or abnormal bleeding.
An ordinary intestinal dewormer doesn’t automatically protect against lungworm. A routine stool test may also be insufficient; your vet may need a specific test or samples collected over several days.
Mention slug or snail exposure if your dog develops unexplained respiratory symptoms or bleeding problems. esccap.org
Heartworm
Heartworm is transmitted by mosquitoes. It isn’t just a travel concern for everyone reading this.
In the United States, the American Heartworm Society recommends year-round prevention and annual testing. Dogs can be infected before obvious symptoms appear, and stool testing doesn’t detect heartworm. American Heartworm Society
For readers in Canada, Australia, the UK, and other countries, the appropriate plan depends on where you live and where your dog travels. Ask your vet about local risk and any testing needed before starting or restarting prevention. canadianveterinarians.net
Arrange travel advice well before departure. Don’t wait until your dog develops symptoms.
What we do: check carefully, and know what we can’t see
We want to understand what we’re giving our dogs and why.
That means considering their exposure and choosing an appropriate plan with our vet. It also means following that plan properly.
Don’t reduce doses, split tablets unless the instructions allow it, or stretch treatment intervals on your own. An incorrect dose or missed treatment can leave a dog unprotected.
We regularly check our dogs’ stool and watch for changes.
If a dog scoots across the floor, repeatedly licks around the anus, or seems itchy there, we take a closer look. But those signs don’t automatically mean worms. Anal gland problems and other conditions can cause similar behavior.
And looking has limits.
You might spot a tapeworm segment or an adult roundworm. Most eggs and larvae are invisible to the naked eye. A normal-looking bowel movement tells you very little about whether parasites are present.
That’s why we combine observation with veterinary advice, testing, and treatment where appropriate.
What a stool test can—and can’t—tell you
Laboratory stool testing can be a useful part of a parasite-control plan.
A single negative result doesn’t rule out every infection. Your vet may request samples from several days, repeat testing, or a test designed for a particular parasite.
Routine stool testing also doesn’t replace heartworm testing or any preventive medication your dog needs.
The useful question is: which parasites does this test check for, and what does my dog still need protection against?
How often should you deworm?
There isn’t one schedule that works for every dog in every country.
Your dog’s age, location, travel, diet, hunting habits, and household all matter. So does the product: different medications cover different parasites.
In the United States, CAPC recommends year-round broad-spectrum parasite control alongside regular fecal examinations. General Guidelines for Dogs and…
European ESCCAP guidance uses an individual risk assessment. When intestinal worm risk cannot be clearly assessed, it recommends treatment or appropriate fecal examinations at least four times a year. Higher-risk dogs may need more frequent attention. esccap.org
That isn’t a universal instruction to give every dog a tablet every three months.
Tell your vet if your dog:
- Hunts or eats rodents and other prey.
- Eats raw meat or organs.
- Swallows slugs or snails.
- Travels to other regions or countries.
- Lives with young children or someone with a weakened immune system.
- Has previously had a parasite infection.
Raw feeding can introduce additional parasite risks depending on the ingredients and their handling. Discuss the food and its source with your vet.
A one-time deworming treatment isn’t a vaccine. It treats the susceptible parasites covered by that medication; it doesn’t make your dog permanently resistant to reinfection.
Preventive products provide protection through their prescribed treatment schedule. Keep to that schedule and use your dog’s current weight when selecting a dose.
Hygiene: simple steps that matter
Pick up your dog’s poop promptly.
Wash your hands after handling waste and before eating. Encourage children to wash their hands after playing outside.
Keep sandboxes covered, prevent dogs from soiling children’s play areas, and avoid letting dogs lick young children’s faces.
These habits help reduce exposure to parasites. They work alongside veterinary prevention, rather than replacing it.
When should you contact your vet?
Contact your vet if you notice:
- Severe itching, bald patches, or broken skin.
- Visible worms or tapeworm segments.
- A puppy with a swollen belly or poor growth.
- Persistent or bloody diarrhea.
- Repeated vomiting.
- Coughing, breathing difficulties, or unusual fatigue.
- Unexplained bruising or bleeding.
- Weight loss without an obvious reason.
Severe breathing difficulty, collapse, or significant bleeding needs urgent veterinary attention.
If possible, bring a fresh stool sample or a worm or segment you’ve found in a securely closed container. A clear photo may also help.
The main things to remember
- Flea control involves your pets and their environment.
- Keep treatment going for the recommended period, because developing fleas can emerge later.
- Never use a dog-only product on a cat.
- Ask about medication sensitivities, including MDR1 testing when appropriate.
- Home remedies aren’t reliable substitutes for effective prevention.
- You usually can’t see a worm infection just by looking.
- Parasite risks differ by location, so prevention needs to reflect where your dog lives and travels.
- Testing and prevention work together. One negative stool sample doesn’t cover every parasite.
- Don’t change doses or treatment intervals yourself.
We want a plan that gives our dogs the protection they need, with a clear reason for each treatment.
How do you handle fleas and worms with your Shepherd? Share your experience in our Silly Shepherds Facebook group.
Follow us on YouTube, TikTok, and Instagram for updates on Zara and Odin.
🐕 Experience, with the facts checked
We write from nearly thirty years of living with German Shepherds, but we’re not veterinarians. We describe personal experiences as personal experiences and check medical information against veterinary and public-health sources. Choose your dog’s products and prevention schedule with your vet. And when something is uncertain, we say so.
Sources and further reading
- Companion Animal Parasite Council — General Guidelines
- Companion Animal Parasite Council — Fleas
- ESCCAP — Worm Control in Dogs and Cats
- American Heartworm Society — Heartworm in Dogs
- Washington State University — Breeds affected by the MDR1 mutation
- FDA — Safe Use of Flea and Tick Products
