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Intestinal worms
Worms that live in the gut (roundworms, hookworms, whipworms and tapeworms). Very common in puppies, who often get them from their mother.
Go to the vet now if…
- Very weak, or black, tarry stools: in puppies, hookworms can cause severe anemia.
- Repeated vomiting, a swollen, painful belly, or straining without passing stool.
- Trouble breathing.
- Very tired, not eating, or bloody diarrhea.
How you notice it
- A pot belly on a thin body.
- Poor growth or a dull coat.
- Diarrhea, sometimes with mucus or blood.
- Vomiting; sometimes worms show up in vomit or stool.
- Worm segments in the stool or stuck to the fur around the anus.
- Coughing, because larvae can pass through the lungs.
What to do
- Book a vet visit and bring a stool sample; if you see worms or segments, take a photo.
- Deworm only with the product and schedule your vet gives you: puppies need several rounds.
- Pick up poop right away, at home and on walks: eggs can contaminate the ground for a long time.
- Wash your hands after handling your puppy or poop, and keep children away from soiled areas and from putting dirt in their mouths.
- Keep fleas under control as your vet advises: swallowing a flea can give a dog the most common tapeworm.
- Don't feed raw meat.
Does it spread?
- To other dogs: yes
- To people: yes
Yes. Other dogs catch them from eggs in poop. Some, like roundworms (Toxocara) and certain tapeworms, can infect people, especially children: wash your hands and always pick up poop.
How to prevent it
- Regular deworming on your vet's plan (it's in the health calendar).
- Stool tests whenever your vet recommends them.
- Always pick up poop and control fleas.
Sources
- Gastrointestinal Parasites of Dogs - Dog Owner Version (Peregrine AS; updated May 2026)
- CAPC Guidelines: Ascarid (Dogs) - clinical signs, zoonosis and control (updated 28 Feb 2025)
- ESCCAP Modular Guide 1: Worm control in dogs and cats (2026 update) - clinical signs and preventing zoonotic infection
- 13 Animal emergencies that require immediate veterinary consultation and/or care
- Disorders of the Stomach and Intestines in Dogs - Dog Owner Version (Defarges A et al.; updated Jun 2026)
- Diarrhea (canine health topics; edited and updated 3/2024 by Riney Canine Health Center veterinarians)
- Diarrhoea in dogs (PDSA Pet Health Hub; written by vets and vet nurses, May 2023)
- CANIGEN MHA2PPI liofilizado y disolvente para suspensión inyectable para perros - Ficha técnica (rev. 06/2021)
- MAXIVAC PRIMA DP liofilizado y suspensión para suspensión inyectable para perros - Ficha técnica (RCP rev. 08/2024)
- Vaccine Failure and Other Adverse Events in Animals - Professional Version (Tizard IR; full review Oct 2023, updated Sep 2024)
- Nobivac DHPPi lyophilisate for suspension for injection for dogs - Summary of Product Characteristics (last revised Aug 2025, approved Dec 2025)
This is general information, not a diagnosis. Your vet is the one who can tell what's wrong and what to do.