Module 2: Preventive health care and health surveillance

Parasite Control Best Practices

ASV Guidelines Statement on Parasite Control

“Shelters have a responsibility to reduce risk of parasite transmission to humans and animals. An effective parasite control program should be designed with the supervision of a veterinarian. Animals should receive treatment for internal and external parasites common to the region and of public health concern as well as for any obvious detrimental parasite infection they are harboring. Ideally, all animals receive parasite prevention on entry and regularly throughout their shelter stay. At a minimum, all dogs and cats must be treated for roundworms and hookworms starting at intake…”

Several studies have found that gastrointestinal parasites are more common in shelter dogs and cats than in owned pets. Here is a summary of the key findings.

Key Takeaways for GI Parasites

  • Gastrointestinal parasitism is more common in shelter dogs and cats than owned pets
  • Most dogs and cats enter shelters harboring at least one GI parasite that is pathogenic and/or zoonotic
  • Roundworms, hookworms, and coccidia are the most common GI parasites in shelter dogs and cats
  • Roundworm or hookworm infection is not associated with any specific risk factor such as age, sex, source (stray or owned), body condition score, diarrhea
  • Coccidiosis is typically a disease of puppies and kittens <6 months old

Most dogs and cats enter shelters harboring at least one GI parasite that is pathogenic and/or zoonotic, making parasite control within shelters both an animal health and a public health priority. Animals adopted from shelters with untreated, or ineffectively treated, parasite infections pose ongoing risks for animal and human health.

Important criteria for a shelter parasite control protocol include:

  • protecting the health of each animal
  • preventing transmission between animals
  • reducing environmental contamination
  • preventing zoonotic infections of shelter staff, volunteers, and adopters

Creating individualized treatment plans for each animal based on fecal analyses is impractical and expensive. It is more practical and cost effective to routinely administer parasiticides as a preventive for the most common and important GI parasites, starting at intake and continuing throughout stay in the shelter. The most common GI parasites in shelter dogs and cats are roundworms, hookworms, and coccidia (Cystoisospora). Parasite control protocols should include empirical treatment for these parasites.

In addition to GI parasites of concern for animal health and public health, preventive health care protocols should include empirical treatments for fleas and ticks starting at admission and continuing through shelter stay. Multiple infectious agents can be transferred between dogs and cats and to humans by fleas and ticks. A variety of topical and oral products are available for flea and tick control, and many of these also provide additional control for GI parasites and other internal and external parasites such as heartworm, mites, and lice.

The Companion Animal Parasite Council (CAPC) provides guidelines for treatment and prevention of internal and external parasites in dogs and cats. CAPC also provides a comprehensive list of parasiticide products and their activity against various internal and external parasites. This is a very important resource for veterinarians to bookmark and use when deciding on which parasiticides to use in shelter dogs and cats.

Here is a quick reference guide for parasiticide products commonly used in shelters and their efficacy for internal and external parasites, including extralabel use supported by published evidence.

Intake Protocols for Parasite Control

Evidence-based best practices for a parasite control protocol include empirical treatment of dogs and cats at intake for roundworms, hookworms, coccidia (puppies and kittens only), fleas, and ticks. Treatment for roundworms and hookworms should be repeated 2 weeks later to break the life cycle of these parasites. In addition to empirical treatment for the internal and external parasites of concern, adopters should be referred to a veterinarian for continued care of their new pet, including follow-up parasite diagnostic tests and treatments as needed.

The ASPCA created a table of general recommendations for parasite control in shelter dogs and cats that is a useful reference for shelter staff.

Best Practice Protocol for Parasite Control

Parasite Adult Dogs and Cats Puppies and Kittens
Roundworms/Hookworms Pyrantel pamoate at intake and repeat 2 weeks later* Pyrantel pamoate at intake and repeat every 2 weeks while in shelter
Coccidia Ponazuril or toltazuril at intake**
Fleas/Ticks Topical or oral preventive at intake Topical or oral preventive at intake***

*Fenbendazole can be substituted for pyrantel pamoate but requires daily administration for 3 days at intake and repeated 3 weeks later. This is more expensive and labor intensive for staff than administering one dose of pyrantel at intake and 2 weeks later.

**Ponazuril (toltrazuril) oral solution formulated by veterinary compounding pharmacies such as Wedgewood and Roadrunner (Covetrus). Treatment with 50 mg/kg daily for 3 days is more effective than treatment with a single dose of 20 to 50 mg/kg (Litster.Veterinary Parasitology.2014:319).

***Most products are labeled for puppies and kittens 8 weeks of age and older. Capstar (nitenpyram) for killing adult fleas is safe for puppies and kittens at least 4 weeks old and 2 pounds of body weight.

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