Puppy Deworming: Why 'Early and Often' Still Holds True

When your client brings home their happy new puppy, parasitic diseases are likely the last thing on their mind. Yet, without appropriate protective measures, intestinal worms can be devastating for both the puppy and pet owner. Not only do intestinal worms pose health risks to the puppy, they also pose zoonotic risks to family members. 

Deworming puppies “early and often” will ensure they are protected against hookworm, roundworm, whipworm and tapeworm infections. Treating your puppy with a broad-spectrum dewormer may help reduce the risk of transmission to other members of the household.

Of course, worms aren’t a puppy-only issue. It’s important for us to regularly talk about intestinal parasites with all clients and stress the importance of deworming dogs of all ages, especially as recent studies demonstrate an increase in hookworm and roundworm prevalence (1).

Intestinal Parasites in Puppies

Many of us think of intestinal parasites and puppies as going hand-in-hand, and rightly so. Although in reality not every puppy has worms, it is safe to assume that all puppies will be exposed to intestinal parasites at some point before they reach adulthood. Ascarids and hookworms have previously been shown to be most common in dogs less than 1 year of age, but the same study also found that dogs less than 6 months of age were least likely to be given prophylactic deworming agents (2). These findings demonstrate an important gap in client education that all veterinary professionals should be working to address.

Puppies are at particular risk for acquiring intestinal parasites via the transplacental and transmammary routes of transmission. Transmammary transmission of hookworm and roundworm is of particular concern, as puppies will be repeatedly exposed when nursing. Thus it is important to address intestinal parasites at intervals throughout the first two months of life to ensure infections are cleared.

Puppies infected with intestinal parasites commonly experience chronic ill-thrift, failure to gain weight, dull haircoat, diarrhea, vomiting, and anemia. Puppies infected in utero or during ingestion of colostrum may develop a fatal anemia as early as 1-2 weeks of age, long before their first visit to the veterinary clinic.

Whenever possible, both veterinarians and staff must work to educate breeders and owners of pregnant and nursing animals about the importance of implementing a deworming protocol before and after whelping.

Diagnosing Intestinal Parasites in Puppies

Fecal examination via centrifugation remains the best diagnostic tool for intestinal parasites, although this type of screening does have limitations. Newer tests are available that may increase the ability to diagnose. Because puppies can be infected via transplacental and transmammary routes, severe parasitic infections can develop as early as 2-3 weeks of age, often before eggs are shed in the feces. Additionally, some parasitic species such as tapeworm and whipworm only shed eggs intermittently and are notoriously difficult to diagnose via fecal samples. Thus, fecal sampling alone is not a reliable means of addressing parasitic infections and should always be combined with routine prophylactic deworming in puppies.

There is no single deworming medication that addresses all parasitic species, so fecal sampling is still necessary to guide medication choices, monitor client compliance, and identify treatment failures. The Companion Animal Parasite Council (CAPC) recommends that puppies receive fecal examinations at least four times in their first year of life, beginning with their first visit to the veterinary clinic. 

Because false negatives can occur when using fecal samples to identify intestinal parasites, the adage “early and often” still holds true when it comes to deworming puppies. According to the American Animal Hospital Association’s Canine Life Stage Guidelines, puppies should begin broad-spectrum deworming treatments at 2 weeks of age. These treatments should be repeated every two weeks until the puppy reaches 8 weeks of age and can be started on a monthly parasite protection regimen.

For pregnant dogs, CAPC recommends two to four high-dose Ivermectin treatments or daily Fenbendazole beginning at day 40 of pregnancy and continuing through day 14 of lactation. By treating both dam and offspring, the transmission of intestinal parasites and environmental contamination with parasite eggs is greatly reduced.

Puppy Deworming Schedule

All puppies should be treated with a broad-spectrum deworming medication at 2, 4, 6, and 8 weeks of age to address intestinal parasites. It’s important for practices to reinforce to pet owners, shelters, and breeders the need for this protection before the puppy’s first vet visit. Nursing dams not already on a parasite protection regimen as outlined above should be treated at the same time as their pups, which will greatly reduce the risk of transmission via both the fecal and transmammary routes.

In addition to deworming treatments, good sanitation of the environment is necessary to protect against re-infection. Bedding for dams and puppies should be kept clean and dry, and changed frequently to reduce contamination of the environment. Owners of pregnant and nursing dogs should be advised to house their dogs in concrete runs, rather than dirt, to allow for easy disinfection and reduce the likelihood of eggs being harbored in the environment.

All puppies should be started on monthly year-round parasite control medications as soon as they are old enough to do so. This should include coverage for fleas, ticks, heartworm, and intestinal parasites. Interceptor^® Plus (milbemycin oxime/praziquantel) is an effective option for protection against heartworm disease, hookworm, roundworm, whipworm, and tapeworm that can be given to puppies as early as 6 weeks of age and weighing at least 2 pounds. This ensures that there is no gap in coverage between the puppy’s initial deworming series and the start of monthly parasite control medication. For flea and tick control, Credelio® (lotilaner) is a monthly chewable that can be started in puppies as early as 8 weeks of age and weighing 4.4 pounds or greater.

See important safety information for Interceptor® Plus and Credelio® below.

For any dog not maintained on monthly broad-spectrum parasite protection, CAPC recommends fecal examinations and treatment with a broad-spectrum anthelmintic medication at least four times annually.

Unfortunately, many puppies do not visit the veterinary clinic until after they have been weaned and sent to new homes. Because of this, many puppies are already infected and shedding eggs into their new environments, increasing the risk for transmission to both humans and other pets in the household. These puppies may also be carrying a heavy worm burden, which can lead to complications such as anemia, intussusceptions, and GI signs. In addition to implementing a deworming regimen for these puppies, pet owners must also be educated on the importance of good sanitation to reduce disease transmission. 

On the other hand, some shelters and breeders will begin a puppy’s deworming series soon after birth. Depending on the breeder, this process may or may not be overseen by a veterinarian. Close contact with other dogs in a breeding facility or shelter environment increases the puppy’s likelihood of having been exposed to parasites, so it is especially important that new pet owners obtain deworming records from the breeder whenever possible. You will need to review these records carefully to identify any gaps in coverage which may put both the puppy and the family at risk for illness.

Encouraging Client Compliance

Client compliance is perhaps the largest hurdle that must be overcome when it comes to parasite protection. A recent study that looked at the incidence of adult heartworm infections in dogs in the United States revealed that approximately two-thirds of the dogs in the country received no heartworm prevention each year (3). From this, we can safely assume that these dogs were not being adequately protected from intestinal parasites, either. Pet owners who are administering heartworm prevention aren’t necessarily following their vet’s recommendation for year-round protection.

This reiterates the importance of frequent, open conversations about the risks of parasites and the use of parasite control medications. Many pet owners don’t understand how and where pets are exposed to parasites or even the fact that there are multiple types of worms that can affect their dog’s health. To improve compliance and adherence to parasite control programs, we need to make sure clients are aware that their pets are frequently being exposed to parasites within their own environments and that many of these parasites won’t cause highly visible signs early after infection. In addition, studies have shown that consistent and clear recommendations from the entire veterinary team are essential to help pet owners understand and remember to follow appropriate protocols. Frequent follow-up with the client is necessary to reiterate these recommendations (such as through your reminder system) and identify problems that may impact compliance.

Meeting Your Patient’s Parasite Protection Needs

Ultimately, there is no “one-size-fits-all” regimen for deworming dogs, particularly puppies. Product choices and the timing of their use must be carefully considered in light of the individual patient’s history, lifestyle, risk factors, and concurrent medical conditions. When it comes to lifestyle and risk factors, remember that what your clients tell you their dog does and what the dog actually does can be two different things. The dog could very well be exposed to certain risks that the pet owner has failed to inform you about. By taking steps to cover all parasites that dogs could be at risk from, you can ensure patients receive maximum protection right from the start.

Disclaimer: The author received compensation from Elanco US Inc., the maker of Interceptor® Plus and Credelio®, for her services in writing this article.