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Communication Guide: Busting Common Canine Intestinal Parasites Myths



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Communication Guide: Busting Common Canine Intestinal Parasites Myths
Sponsored by Elanco Animal Health

Despite the high prevalence of parasitic infection in puppies, several myths exist regarding parasitic disease.

The prevalence of intestinal parasitism in pet dogs ranges 1.2%-5%, with many dogs showing minimal to no clinical signs.1-3 Dogs younger than 6 months of age have a higher risk for both roundworm and hookworm parasitism than do adult dogs. With the exception of whipworms, intestinal parasites are much more commonly identified in this age group of young dogs.2 Regardless of whether clinical signs are present in a patient, intestinal parasites pose health risks not only to pets but also humans in the household. 

Myth #1

If you don’t see them, they’re not there.

Although fecal flotation results are common first-line diagnostic indicators in puppies and adult dogs at wellness and sick visits, there is a high risk for false negative results that ranges 15.6%-93.7%.4 

Microscopic parasitic eggs may not be consistently shed in the feces for a variety of reasons. Many parasitic infections undergo intermittent shedding, which could result in false negative results depending on the frequency of fecal testing.2 In addition, the flotation results may reflect the prepatent period of the parasitic lifestyle, when a patient is infected with a parasite but parasitic shedding has yet to occur. 

The fecal flotation technique being used can also affect results, as can the misidentification of parasitic eggs. 

Myth #2

Parasites only affect outdoor animals.

Contrary to popular belief, an outdoor lifestyle is not required for the transmission of intestinal parasites. Nearly all puppies and kittens are infected with parasites in utero via transplacental transmission, resulting in the presence of intestinal parasitism at birth.5 In addition, transmammary infection is possible during nursing. 

Direct or indirect contact with other infected animals also poses a risk for infection—namely, via the fecal–oral route. This can occur within the home or in other shared environments (eg, dog parks, pet care facilities). Puppies with minimal outdoor contact (eg, those that only go outside for several minutes a day) and limited interactions with other dogs are still at risk for parasitic infection.

Myth #3

Puppies and dogs are the only family member at risk.

Intestinal parasitism not only poses a risk to household dogs but also to human family members. Toxocariasis (ie, roundworm infection) is the most common human parasitic worm infection in the United States,6 and ancylostomiasis (ie, hookworm infection) is commonly acquired through travel to the tropics or subtropics.7 Roundworms can cause visceral and ocular larval migrans, whereas hookworms can cause cutaneous larval migrans.6-9 

Children are most at risk, especially if they share an environment with a dog or play outdoors in parks or sandboxes.6 

The risk for zoonotic infection for both adults and children can be reduced by frequent hand washing, routine pet deworming, and appropriate disposal of pet feces. In addition to deworming, the year-round use of broad-spectrum heartworm preventives can help treat and control some intestinal parasites.10  

Myth #4

Only seasonal prevention is necessary.

Although clients may be inclined to use preventives only seasonally, puppies remain at a continued risk for exposure from a variety of sources throughout all seasons.11 In addition, non-worm intestinal parasites, such as Giardia spp and Coccidia spp, are shed annually and remain contagious in the environment for an extended period post shedding, resulting in an increased susceptibility for infection.2 Year-round parasitic prevention is thus recommended to protect pets against environmental organisms that may remain infectious in the cold months, as well as organisms spread through vertical transmission. 


Intestinal parasites pose a threat not only to puppies and adult dogs but also to non-canine family members—young children and immunocompromised individuals in particular. Clinical signs can be mild, even absent, in some patients. Further complicating a diagnosis, shedding may not be evident in the feces despite an active infection. Although several diagnostic challenges exist, it is crucial to monitor dogs for intestinal parasitism and treat appropriately when indicated. Avoiding the common pitfalls and misconceptions of intestinal parasitism is vital to not only optimize patient care but also client satisfaction.


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