Deworming your puppy

By Dr. Mikel Maria Delgado, PhD

One of the most important things you can do to ensure your puppy’s health is to protect them from both external and internal parasites. Some of the most common parasites affecting puppies are various species of worms, also known as helminths. They can be contagious (infecting other pets in your home), zoonotic (meaning they can spread to humans), and in some cases, can even be fatal to your pup. Worms can be passed from the dam to puppies in utero, or puppies can get worms from nursing on an infected mother’s milk. Some worms can survive in an environment for months, so active prevention is critical to protect puppies. 

Some puppies will show signs of infection, such as diarrhea and/or weight loss, but others will appear healthy -- you can’t always tell from outward appearance that a dog has worms. This is why routine deworming is critical in preventing and treating some forms of parasite infection. Deworming medications are generally considered safe and very effective, with minimal side effects.

There is a long list of parasites puppies may need treatment for, including roundworms, hookworms, tapeworms, whipworms, and heartworms. Unfortunately, not every medication is effective against every parasite, or even against every life stage of some helminths (which can have egg, larval, and adult stages). This is why repeated administration is important and in some cases, you may have to administer more than one type of medication to your pup.

Companion Animal Parasite Council recommends deworming puppies multiple times: generally four initial treatments, two weeks apart. This should be followed by monthly broad-spectrum control (e.g., a standard heartworm preventative that also protects against some intestinal parasites) for the dog’s life. A preventative care plan for  your dog that factors in their lifestyle and risk for specific parasites should be developed in consultation with your veterinarian.

How are puppies/dogs diagnosed with worms?

It is recommended to treat all puppies preventatively, regardless of whether they show signs of parasitic infection.  Many worms and their eggs are too small to be seen by the human eye, although you may have observed adult tapeworms or roundworms in your puppy’s feces - which can look like pieces of rice or spaghetti. This is a definite sign your pup is infected!

Fecal testing can identify some parasites, but it is important to understand that it cannot identify all infections, and the accuracy of a fecal test (called a “fecal float”) can depend on factors such as the lifestage of the parasite or the age of the sample. If your puppy has diarrhea or seems otherwise unwell, your veterinarian will likely ask for a fecal sample, and may want to check multiple samples to ensure efficacy of any treatments.

Annual heartworm testing by your veterinarian is recommended to maintain a prescription for monthly heartworm preventatives. Heartworm is spread by mosquito bites, and in many areas of the United States it has increased in prevalence. Heartworm is treatable if caught early, but treatment is painful, extensive, and expensive. Heartworm can cause permanent damage to the heart and severe cases may be fatal  so prevention is a much safer strategy.

Treatments for parasitic infection

There are several medications that your veterinarian may prescribe for your puppy. Most of these medications are administered orally. The most commonly prescribed medications include Pyrantel pamoate (Nemex/Strongid), Fenbendazole (Panacur/Safe-Guard), and Praziquantel (Drontal). More than one medication may be used in combination to ensure coverage of all potential worm infestations. Some of these medications are not safe for neonatal or very young puppies, and may not be safe for pregnant dogs. The best and safest approach is to work with your veterinarian and follow their guidance for treatment and prevention. 

When you get a puppy

Make sure you find out from the breeder or rescue organization what deworming treatments your puppy has received and when. This information will help your veterinarian develop the best plan for treatment and monitoring under your care. Remember that multiple treatments are the standard protocol, and so even if your pup was “dewormed” by the breeder or rescue, you may need to administer additional medications. 

References

AAHA Guidelines: Parasite Control

American Heartworm Society: Heartworm Basics

Duijvestijn, M., Mughini-Gras, L., Schuurman, N., Schijf, W., Wagenaar, J. A., & Egberink, H. (2016). Enteropathogen infections in canine puppies:(Co-) occurrence, clinical relevance and risk factors. Veterinary microbiology, 195, 115-122. https://www.sciencedirect.com/science/article/pii/S0378113516303492