Pets and Parasites Are on the Move. Here’s How It Affects Your Parasite Control Recommendations

Posted by Jackie Brown

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Pet owners often decline routine fecal testing and year-round, broad-spectrum parasite control, feeling that it’s an unnecessary expense. If you need another talking point to help convince reluctant clients about the importance of parasite testing and protection, consider this: Pets are on the move more than ever before, and that means parasites are, too.

Animal Relocation: Benefits and Risks

Animal relocation programs—where homeless animals are moved from areas with high homeless pet overpopulation to locations that have a higher demand for adoptable pets—are just one source of pet movement. Such programs are growing in popularity because they work.

“Animal relocation programs are a key component of a multifaceted strategy to save lives,” says Brian A. DiGangi, DVM, MS, Dipl. ABVP (Canine & Feline Practice, Shelter Medicine Practice), senior director of shelter medicine, shelter outreach for the American Society for the Prevention of Cruelty to Animals (ASPCA). “Not only does sending animals on transport provide a positive outcome for those pets and boost staff morale, it frees up resources to improve care and create opportunities for the animals that remain in the shelter and community.”

Since 2014, the ASPCA has helped relocate more than 153,000 homeless pets by way of 6,700 trips to communities where they have greater chances for adoption (1). The ASPCA’s animal relocation program works with more than 40 source shelters across 27 states, nearly 100 destination shelters across 35 states, and five overnight waystations (2). The ASPCA follows best practices for animal relocation and continues to develop and share new insights with the animal welfare field. 

Smaller scale animal transport happens as well, with independent rescue organizations moving homeless pets throughout the community, at times, across state lines and even internationally, to improve their chances of being adopted.

“We’re also seeing massive movement of hurricane re-location animals, and with a shortage of adoptable animals in the Northeast, bringing a lot of animals out of the Southeast up to the Northeast,” says I. Craig Prior, BVSC, CVJ, board member and immediate past-president of the Companion Animal Parasite Council (CAPC). “Because of the movement of animals, veterinarians should no longer base their parasiticide recommendations upon historical norms.”

More Pets Are on the Go

 Owned pets are on the move too, with today’s pet owners being far more likely to take their pet with them everywhere they go, whether they stay in their community visiting parks and beaches, or when they travel or move across the country. “Snowbirds” now tend to bring their pets with them when they move to warmer locales in winter.

Whether dogs visit dog parks or other common areas, it’s more important than ever to urge pet owners to use year-round broad-spectrum parasite control that includes tapeworm and whipworm coverage, and opt for fecal testing at least twice a year. 

“What we’ve seen over the last 10 years is an increase in the number of dog parks and in that same time period, we’ve seen a 47 percent increase in the number of hookworm-positive cases [from 2012 to 2018] (2),” Prior says. “Part of this is, [many] people do not pick up after their dogs. A female hookworm can lay thousands of eggs and those eggs contaminate the environment. Even once the stool is broken down, the eggs can survive in the soil for months under the right conditions.”

While a direct correlation can’t be made between the growth of dog parks and changes in prevalence of hookworm, a recent study of dog parks across the U.S. found hookworm to be the most commonly detected nematode. Intestinal parasites were found in 1 in 5 dogs and 8 out of 10 parks, the study revealed (3).

How Does This Affect Parasite Control Recommendations?

Parasitic risks appear to be changing, likely due to multiple factors. Dog relocation and lack of pet owner compliance could be among the potential contributors.

In a perfect world, all pets entering shelters would receive prophylactic deworming, treatment for external parasites, and administration of heartworm preventive. The ASPCA offers general parasite control recommendations for shelter dogs and cats, and all ASPCA transports require animals to have prophylactic deworming and external parasite treatment, as well as heartworm testing of adult dogs.

But it has been found that prophylactic deworming and other parasite control may not always happen. According to one study, which surveyed 193 individuals associated with animal shelters and rescues across the United States that receive transported animals, only 35.2 percent of organizations had pre-transfer requirements for heartworm testing, treatment and/or prevention, and only 23.8 percent had pre-transfer requirements for fecal testing and deworming (4).

After adopting a dog, all owners are told to take their new pet to a veterinarian for an exam, but compliance is often an issue. “When does that owner decide to take their dog to a veterinarian?” Prior says. “The next day? In two weeks? In two months? A year? We don’t know. Most of them will eventually go, we just don’t know when.”

As a result, communities may have higher parasite loads, with possibly different parasites, than historically seen in the past.

Adopted Pets: Questions to Ask, Steps to Take

When seeing a newly adopted pet, ask if the pet was transported from another community, state, or even country. This is especially important when it comes to knowing a pet’s heartworm status (4).

“In most cases, it is a good idea to repeat heartworm testing for dogs six months from the date of the last known test to help detect an infection acquired prior to arriving at the shelter,” DiGangi says. “A dog will occasionally test positive for heartworm disease on a second test even though the initial test at the shelter was negative and the dog had been maintained on preventive throughout that time.”

Fecal testing and broad-spectrum parasite control are especially critical for adopted pets with unknown medical history. Asking probing questions of owners of newly adopted pets can not only determine the pet’s risk level, but also help drive the point home to the pet owner about the importance of broad-spectrum parasite control and fecal testing for all pets. Consider the following:

    • Does the pet owner know anything about the pet’s background or medical history?
    • How long was the pet housed in a shelter?
    • Does the owner plan to take their pet to dog parks, community parks, or other places dogs congregate?
    • Does the dog exercise off-leash or is the dog ever out of sight?
    • Do any immunocompromised individuals live with or visit with the pet?
    • Does the family have small children at home?

“You’re not just protecting the pet, you’re protecting the family,” Prior says. “If we don’t do it, who will? Rabies is required by law, but how often do you see a rabies case? We’re all very forthright about saying you’ve got to get your rabies immunization for your pets. Well, why shouldn’t we be doing the same thing with intestinal parasites?”  

Disclaimer: The author received compensation from Elanco US Inc., for her services in writing this article.   

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  1. ASPCA Animal Relocation map. Retrieved from
  2. The ASPCA Gives 100,000 Animals Brighter Futures Through National Relocation Program. Retrieved from
  3. Drake, J., Carey, T. Seasonality and changing prevalence of common canine gastrointestinal nematodes in the USA. Parasites Vectors 12, 430 (2019)
  4. Stafford, K., Kollasch, T.M., Duncan, K.T. et al. Detection of gastrointestinal parasitism at recreational canine sites in the USA: the DOGPARCS study. Parasites Vectors 13, 275 (2020).
  5. Simmons KE, Hoffman CL. Dogs on the Move: Factors Impacting Animal Shelter and Rescue Organizations' Decisions to Accept Dogs from Distant Locations. Animals (Basel). 2016;6(2):11. Published 2016 Feb 3. doi:10.3390/ani6020011
  6. Drake, J., Parrish, R.S. Dog importation and changes in heartworm prevalence in Colorado 2013–2017. Parasites Vectors 12, 207 (2019).