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Do All Puppies Have Worms When They Are Born

↯ Key takeaway points

  • Most, but not all, puppies are born with worms and can obtain them from their mothers; worms such as roundworms and hookworms can be transferred this way.
  • Other types of worms, like tapeworms and whipworms, can be obtained through contact with infected soil or animals.
  • Symptoms of worm infestations can include a pot belly appearance, vomiting and pneumonia, and anal itching and lethargy, among others.
  • Puppies should be dewormed every two weeks until they are 12 weeks old and monthly afterward until they are six months old; flea prevention is recommended to prevent worms from being transmitted.
A pet lover passionate about educating readers about animal health and care. Love reading studies and recent research.
Zoo and wildlife doctor in veterinary medicine passionate about animal welfare and preventive medicine.
Published on
Thursday 6 October 2022
Last updated on
Monday 17 July 2023
Do All Puppies Have Worms When They Are Born
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Newborn puppies are pretty much helpless creatures. They can’t tend to themselves, so they depend on their mom for their nourishment. Also, they have a weak immune system, so they’re vulnerable to diseases. We ask ourselves, aside from illnesses, do all puppies have worms? If so, where did they get that? Let’s find out in this article.

Are All Puppies Born With Worms?

Research in epidemiology in 2022 stated that 50% of puppies as young as 2 weeks old have inherited Toxocara canis via in-utero transmission. Also, according to the study, 70% of 12-week-old dogs got more worms from lactogenic transmissions. Moreover, scientists concluded that 75% of puppies got parasites through vertical transmission.

Most, but not all, puppies are born with worms. For instance, if the mother dog has complete vaccines and deworming sessions, then the chances of its pup getting worms are slim to none. Yet, veterinarians suggest that puppies as young as 2 weeks old should have deworming. Well, that is to protect them from the horizontal transmission of worms.

It’s normal for puppies to have worms through secondary exposure. That’s what happens when they come in contact with infected feces or animals. Moreover, worms such as roundworms, hookworms, whipworms, tapeworms, and heartworms are the common invasive parasites in young dogs.

Pregnant dogs infect their young with roundworms and hookworms through their bloodstream and milk. Whereas tapeworms and whipworms infection are more invasive. They infect when puppies touch infested soil. Further, the worse one is heartworms, which insect bites transfer to puppies.

A study in 2019 about parasites provides support for the claim. According to the results, there’s soil contamination of geohelminths happening in the world. Animals, especially dogs, ingest worm eggs in public places like playgrounds, beaches, and parks. Afterward, infected dogs also shed those parasitic eggs in their feces.

Is It Normal For Puppies To Have Worms?

It’s normal for dogs to be born with worms since they got them from their mothers. According to a survey in 2007, the most common worm infestation in dogs is the hookworm, which amounts to 19.19%. This is followed by the roundworm, which infected 14.54% of dogs. Next is the whipworm, which infected 14.3% of dogs.

Puppies may get worms through playing with rodents, too. According to experts, rats and mice are prone to tapeworms and pinworm infections. Further, young dogs are also prone to suffering worm infestations by biting roaches. It turns out that roaches are hosts to Physaloptera spp. or commonly called stomach worms.

On the contrary, heartworms are rare in puppies less than one-year-old. That’s because these worms take 5 to 7 months to become adults, so they’re not easily detected. Also, by the time the dog shows signs of infection, the worms already made so much organ damage.

Types of Worms Puppies Can Have

Puppies like to play with dirt and bite stuff. As a result, they’re prone to parasitic infections and diseases. Other times, some dogs are born with worms already. Well, you may want to look at the different worms that can infect your puppy below.


The most common type of worm that infects dogs of all ages is the tapeworm called Dipylidium caninum. Adult worms can grow up to 11 inches. These parasites attach themselves to the small intestines of canines using their tiny tentacles called rostellum. They’re thin, long, and segmented worms that suck nutrients from their hosts’ bodies.

Other than anal itching, puppies born with worms usually don’t show other symptoms. As a result, owners don’t know their dogs are infected. Yet, in rare instances, they cause intestinal blockage. Further, segments of these worms are shed through a dog’s feces, which can infect other animals as well.


Another type of worm that infects dogs is the whipworm called Trichuris vulpis. Some dogs are born with these worms because their mothers were infected during pregnancy. Yet, in other instances, puppies get these parasites through direct contact with contaminated soil and animals.

These parasites grow up to 5 cm and live in most puppies’ large intestines. As a result, they cause severe irritation in the intestines, called trichuriasis. Unlike roundworms, which are asymptomatic, whipworms cause dehydration, diarrhea, and anemia. Also, these worms feed on their hosts’ blood, so, if left untreated, it can cause serious complications and even death.


All dogs are born with worms called roundworms. Well, it’s either they got it from their moms or through ingesting worm eggs. Roundworms or ascarids are one of the most common worms that live in a dog’s gut. They’re thin, spaghetti-like white worms that range from 4 to 6 inches in length.

Roundworms feed from the dog’s gut nutrients. As a result, they can stunt the growth of their host. Although they’re common, they still pose a threat once untreated in puppies. It turns out that these worms undergo tracheal migration. Further, from there they mature and cause cough and pneumonia. 


All puppies are born with worms, and that includes hookworms. These parasitic worms live in a dog’s small intestines. They’re only 2 to 3 mm in length, so they’re hard to see with the naked eye. Also, they like to feed from blood and nutrients from the small intestines.

Moreover, despite their tiny size, they are vigorous feeders. The most common type of hookworm is the Ancylostoma duodenale. Also, a single Ancylostoma worm can devour at least 0.15 to 0.23 ml of a dog’s blood every day. Further, if they aren’t treated properly, they can cause anemia and gastrointestinal bleeding.


All puppies may have worms if their mothers weren’t dewormed before and after the first 45 days of conception. Yet, puppies can also get infected with another variety of worms transmitted by an arthropod. They’re the most dangerous type of parasite because other than sucking blood, they create holes in an animal’s heart and arteries. 

Moreover, the Dirofilaria immitis parasite is the cause of heartworm disease.  Mosquito species of Mansonia, Aedes, and Anopheles are carriers of this disease. That is because, through their bite, they can transfer worm eggs directly into an animal’s bloodstream. Further, they stay in the pulmonary arteries and the heart for 6 to 7 months until they mature. 

How Do You Know If Your Puppies Have Worms

The main reason why puppies are born with worms is because of heredity. Yet, you can’t accurately tell that dogs have worms without assessing their symptoms. For instance, a pot belly appearance in dogs can be due to roundworm infections.

Moreover, worms irritate the small and large intestines’ linings. As a result, dogs suffer from acute bloody diarrhea and chronic weight loss. In worst cases, these can also cause anemia and even death.

Another sign of intestinal parasites in dogs that owners need to watch out for is vomiting and pneumonia. Some worms such as roundworms can travel into the lungs and cause uncomfortable sensations for dogs. Hence, they cough it up in an attempt to subdue them.

Further, cough is also a symptom of heartworms. These kinds of parasites are deadly since they destroy an organ’s function by burrowing holes in it. Other than that, canines can also suffer from anal itching and lethargy

When Should You Deworm Your Puppies?

The Centers for Disease Control and Prevention recommend deworming newborn puppies when they reach 2 weeks of age. From that point, they should be dewormed every 2 weeks until they are 12 weeks old, and then monthly until they are 6 months old.

There are effective medications, such as fenbendazole and mebendazole, that can be used to treat roundworm and hookworm infections in dogs. One example of such medication is the Bayer Quad Dewormer Chewable Tablets, which is suitable for small dogs and puppies weighing under 25 lbs.

Several deworming medications also treat tapeworm and whipworm infections. One such medication is praziquantel, which is commonly used. A generic brand that is often recommended by veterinarians is Elanco Tapeworm Dewormer.

Treating heartworms is more challenging compared to other parasitic worms. Common dewormers are effective against intestinal parasites but not heartworms. The American Heartworm Society advises that all puppies be given heartworm prevention medications no later than 8 weeks of age.

Also, according to the FDA, one of the legal heartworm treatment drugs sold on the market is melarsomine. Hence, most vets suggest buying the generic form of that drug under the brand Heartgard. This deworming medicine works for puppies as young as 6 weeks old.  

On the contrary, some worms resist treatment. For instance, research in 2019 about dog parasitology stated that some hookworms became resistant to the dewormers such as pyrantel pamoate, mebendazole, or albendazole. 

How to Deworm a Puppy

All animals can be hosts to parasitic worms, and our canines don’t make an exception. Worms are invasive creatures, so, if they’re not treated, they can continue to multiply. Vets recommend that all puppies born with worms must have monthly checkups to evaluate their health status. 

The first step in deworming is to know the dog’s age. Take note that the earliest age you can deworm a puppy is at 2 weeks. Dewormers have side effects, so any puppy younger than that age is not strong enough to handle certain doses.

In terms of deworming drugs, there are a few options: oral tablet, powder, solution, and injectables. Remember that you only have to buy the medicine prescribed by your veterinarian. Also, dewormers have doses that are based on a dog’s weight.

For starters, the usual dose for a tablet dewormer is 1 tablet per 20 lbs of body weight. Also, powder dewormers are given in terms of 1 gram per 10 lbs of weight. Next, anti-worm solutions have dosages of 5 tsp in every weight of 5 lbs. Lastly, injectable dewormers, which are usually good for heartworms, have a dosage of 0.0015 mg per pound.  

Are Puppies Born With Worms: FAQs

It’s only common that all puppies get worms at some point in their lives. Yet, these parasites can be deadly if they’re not treated early. As an owner, you need to thoroughly check your dog’s health. Hence, read the frequently asked questions below.  

Can puppies die if they have worms?

Yes, they can. Worms’ natural habitat is the intestines, yet they can migrate into different internal organs and cause damage. Also, they’re bloodsuckers, so their hosts are most likely to suffer from anemia. Further, a loss of one-third of the normal blood amount is fatal to puppies. 

Which type of worm is most dangerous to puppies?

Among all the worms that puppies are born with, heartworms and hookworms are the most dangerous. Hookworms are vigorous bloodsuckers that cause anemia. Meanwhile, heartworms are silent killers in puppies. That’s because as the puppies progress, so as the worms and the damage they caused.

Can puppies be born without worms?

Yes, not all puppies have worms upon birth. That’s because some of the pregnant bitches have updated deworming sessions before mating and after whelping. Yet, to be sure, vets advise owners to deworm their puppies once they reach 2 weeks old.

Can I hold my puppy if he has intestinal worms?

Yes, but you still need to be cautious. For instance, roundworms and hookworms can be passed on through a dog’s lick. Also, tapeworm eggs are sticky, so they can stick to your hand or face when your dog comes close to you.

How often should I deworm my puppies?

Puppies with worms should be dewormed every 2 weeks until they reach 12 weeks old. That’s at least 6 times in 12 weeks. After that, it can be per month until they reach 6 months old following your veterinarian’s advice.

How contagious are puppy worms?

All puppies that have worms are contagious. That’s because they shed their worms through their feces which, in return, infects other animals. Take note that roundworm and tapeworm eggs can infect humans as well. However, in terms of heartworms, humans can’t get those parasites directly from their dogs.  

According to vets, almost all puppies are born with worms. Thus, deworming is very important in keeping your dog’s digestive system healthy. Anti-worm prescriptions don’t only protect canines, at the same time, they protect humans as well from contamination. Further, you should consult a veterinarian for the proper deworming dosage. 

One comment on “Do All Puppies Have Worms When They Are Born”

  1. Angie

    Does anyone have experience with a veteranarian saying puppy is ANEMIC?

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