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As a vet, I have been frequently asked by dog parents why young pups need deworming. Most dog parents are puzzled by the deworming necessity because, as they say, “puppies do not go out, so where could they then possibly pick up worms?”

The simple answer is that puppies need deworming because they can basically inherit worms from their mothers – sometimes, the worms can be acquired while the pups are still in the womb and other times after birth via the milk.

In this article, we will thoroughly explain the worm inheritance routes in puppies. We will also discuss other worm infestation mechanisms and review the different types of worms and their consequences. 

Finally, we will briefly go through the basic deworming protocol for young pups.

 The Different Types of Worms in Puppies 

Puppies can be affected by various different types of worms, including whipworms, roundworms, hookworms, tapeworms, threadworms, lungworms, heartworms, and ringworms.

However, the most commonly encountered worms include roundworms, hookworms, and whipworms. 

Did you know? Because of their high prevalence, association with many severe effects, environmental persistence, and zoonotic potential, these three types of worms were popularly referred by Harold Brown, the late former parasitology professor at Columbia University College of Physicians and Surgeons as the “unholy trinity”.

Can Puppies Be Born With Worms?

Yes, as already mentioned, puppies can be born with worms, more exactly roundworms (Toxocara canis), because their transmission can occur via the transplacental (through the placenta) or transmammary route (through the mammary glands by nursing).

Puppies can also be born with hookworms (Ancylostoma caninum) as these worms, or better said, larvae, can use the transmammary route.

Sadly, yes, puppies can be born with worms

Sadly, yes, puppies can be born with worms

Puppies Born With Roundworms (Toxocara canis)

To understand these routes of transmitting roundworms, we need to review the roundworms' life cycle.

Transplacental Infestation

Roundworm larvae can migrate in various body tissues. If the conditions in the tissue destination are not favorable, they can become encysted (their growth stunts, and they are considered dormant).

If a female dog with encysted roundworm larvae in some tissue is impregnated, the larvae will be reactivated. Once reactivated, the larvae travel through mother dog's umbilical vein and enter the uterus. When they reach the fetus, they target the lungs and liver.

During birth, when the puppy takes its first breath, the lungs will inflate, and the larvae burst out. Then, they use tracheal migration to reach the intestines, where it will take around three weeks to mature into adult worms.

Transmammary infestation

Although the previous transmission route is considered primary, encysted roundworm larvae can also find their way into the mammary gland ducts and milk. As a result, puppies can get infected simply by nursing through their mothers' milk.

Puppies Born With Hookworm

Unlike roundworms, hookworms cannot be transmitted through the placenta, only via the mother’s milk.

Transmammary infestation

Similarly as in the previous case, the hookworm larvae can become encysted and arrested. However, in this case it is not pregnancy that activates them, but the act of parturition (giving birth).

Once activated, the hookworm larvae travel though the mammary gland ducts and enter the milk from where they are secreted together.

Puppies, Worms and Other Infestation Routes 

Now that we have explained why puppies can be born with worms, we should explain some additional worm infestation routes and mechanisms.

For example, all members of the “unholy trinity” can be transmitted orally (sniffing or licking infected feces or contaminated soil, grass, toys, bowls). Hookworms can also be transmitted through the skin.

The consequences of worm infestations in puppies should not be underestimated. A study published in 2012, “Pet roundworms and hookworms: A continuing need for global worming”, states that “Different misconceptions have led the general public and pet owners to minimize the importance of these intestinal worms”.

Sadly, this is true. Worms have detrimental effect on puppies and should not be underestimated.

Problems With Roundworms in Puppies 

Roundworms can cause a variety of problems in puppies. Puppy owners may notice the following signs in puppies who weren't d-wormed:

  • Diarrhea
  •  Vomiting
  •  Weight loss
  • Dull hair
  • Potbellied appearance
  • Eye and nose discharge

The vomit and diarrhea can contain eggs or adult worms – they will be white or light brown, rounded, and up to several inches long (they usually look like spaghetti).

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Problems With Hookworms in Puppies

Hookworms can cause a variety of problems in puppies. Puppy owners may notice the following signs in puppies who weren't d-wormed:

  • Poor growth
  • Weakness
  • Bloody diarrhea
  • Bloody vomiting
  • Weight loss
  • Itchy paws

The vomit and diarrhea can contain visible adult worms – they will be whip-like shaped, with thicker anterior and thinner posterior end.

Since hookworms attach themselves to the intestinal lining and feed on blood, if present in high numbers they can cause anemia. 

A puppy with hookworm-induced anemia will show the following signs and symptoms:

  • Pale gums
  •  Physical activity intolerance
  • Increased respiratory rate
  • Difficulty breathing.

The vomit and diarrhea can contain visible adult worms – they are particularly small (less than an inch long) and look like rice.

Problems With Whipworms in Puppies 

Hookworms can cause a variety of problems in puppies. Puppy owners may notice the following signs in puppies who weren't d-wormed:

  • Watery or bloody diarrhea
  • Vomiting
  • General weakness
  • Weight loss

The vomit and diarrhea can contain visible adult worms – they will be around two inches long and whip-like shaped, with thicker anterior and tapered at the end.

It is best to deworm puppies before worms develop into adults 

It is best to deworm puppies before worms develop into adults 

Deworming Protocols for Puppies 

Early deworming is vital because it is much easier to prevent heavy infestations if there are no migrating larvae. Since eggs are not produced until the larvae reach the adult stage, it is best to deworm puppies before their worms grow up and become adults.

Therefore, puppies need to be dewormed when they are two weeks old (as mentioned, it will take the inherited larvae three weeks to become adults). Then, puppies need deworming every two weeks until 12 weeks old.

After the 12 weeks milestone, puppies can be dewormed on a monthly basis until six or twelve months old. Then, they can be treated as adults and dewormed every three months with a high-quality and effective all-wormer.

More about this here: how often should you deworm puppies? Based on the pup’s lifestyle or habits, the vet may recommend more frequent deworming – for example, if the puppy comes into contact with stray dogs or has the nasty habit of eating other dogs’ poop.

For How Long Do Puppies Poop Worms After Treatment?

Depending on the severity of the infestation, you can see dead worms in your pup’s poop for a couple of days after giving the treatments. 

Sometimes, in cases of particularly heavy infestations, the vet may recommend repeating the deworming before its scheduled date.

Can You Get Rid of Worms in Puppies Without Going to the Vet?

There are many alternative deworming options for dogs based on feeding your dog pumpkin seeds, carrots, apple cider vinegar, coconut, turmeric, and chamomile.

 Although these options may have some degree of efficacy, their long-term use in dogs can be somewhat questionable. 

Therefore, it is best to stick to the official deworming treatments when it comes to keeping your pup or dog worm-free. If you are not sure which de-wormer is best, ask your trusted veterinarian. 

Deworming Protocols for Pregnant Dogs 

While on the deworming subject, we should note that deworming the pregnant mother dog is essential too. Deworming the pregnant dog does not mean the puppies will be born worm-free, but it will drastically reduce the number of worms.

Pregnant dogs should be dewormed when around 40 days pregnant and then two days after giving birth. After this, they can go back to their regular three-monthly deworming schedule.

The deworming product must contain fenbendazole. However, it should be noted that not all deworming treatments are safe for pregnant dogs. You need to talk to your vet and ask for a safe treatment option.

Finally, keep in mind that you also need to protect your dog from fleas. Fleas act as intermediate hosts for tapeworms. Both the fleas and the tapeworms can be fatal for young puppies.

 Once again, it is critical to check with your vet which anti-flea preventives are safe for pregnant and nursing females.

Important Keynotes 

  • Puppies can be born with roundworms and hookworms
  • Not all puppies will be born with worms (in the same litter some puppies can inherit worms and others not)
  • Roundworms are the most common worm from the “unholy trinity”
  • Hookworms are also common – one in five dogs has them
  • Hookworms and whipworms trigger the most severe health repercussions
  • Roundworms and hookworms can infect humans too, while whipworms do not have a zoonotic potential.
  • Puppies need regular deworming starting from the age of two weeks. However, the exact frequency of these treatments will vary based on the pup’s age and needs to be discussed with your vet.
  • While young, they need bi-monthly and then monthly deworming treatments.
  • Once they are six months old, they can be treated every three months same as adult dogs.
  • Worms have a negative impact on the pup’s overall health and wellbeing. 
  •  Puppies with lighter worm infestation may not show any visible signs, while pups with heavy infestations will have swollen abdomens, discharge around the eyes and nose, poor coat quality. As the condition progresses, they will start losing weight, and in severe cases, there will be eggs or grown worms in the puppies’ feces and vomit.
  • In addition, considering that young puppies have underdeveloped immune systems, the consequences of worm infestation can be more severe than in adult vets.
  • Consider that certain parasites (roundworm, hookworm, and giardia) can be transmitted through saliva. Therefore, keeping your puppy up-to-date on its deworming treatments is critical for you too.
  • Always talk to your trusted vet about proper deworming – schedule and type of treatment (brand, form, active ingredients). Sometimes, the pup’s lifestyle can affect the deworming frequency.

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