Detection of Gastrointestinal Parasitism at Recreational Canine Sites in the United States (the DOGPARCS study)

Abstract

Background: The rapid growth in off-leash dog parks provides opportunity for canine socialization activities but carries risk of exposure to intestinal parasites. This study assessed the prevalence of these infections in dogs visiting dog parks.Methods: Fresh defecations were collected from dogs visiting parks in 30 metropolitan areas across the United States. Samples were analyzed by coproantigen immunoassay (CAI) (FecalDx® and Giardia Test, IDEXX Laboratories) and zinc sulfate centrifugal flotation (CF). Owners responded to a questionnaire on their dog’s signalment and use of heartworm/intestinal parasite control medications (HWCM). Results: Samples were examined from 3,006 dogs, 87.9% aged at least 12 months, visiting 288 parks. At least one intestinal parasite was detected in 622 (20.7%) samples, nematodes in 263 (8.8%), with hookworm, whipworm, and ascarids in 7.1, 1.9, and 0.6% of samples, respectively. A sample positive for one or more intestinal parasites was found in 245 (85.1%) parks, with nematodes found in 143 (49.7%). Combined, CAI and CF detected 78.4% more intestinal nematode infections than CF alone. Hookworm and whipworm were detected in all age groups, but ascarids were only detected in dogs less than 4 years. Approximately 42% of dogs aged less than 1 year were positive for nematodes or Giardia. Based on owner reports, HWCM was current for 68.8% of dogs, dogs previously diagnosed with intestinal parasitism were more likely to be receiving a HWCM than those without such history, and a significantly lower (P = 0.0003) proportion of dogs receiving a HWCM were positive for intestinal nematodes compared with those not on such medication.Conclusion: Intestinal parasites, the most common of which were Giardia, Ancylostoma caninum and Trichuris vulpis, were found in 20% of dogs and 85% of dog parks across the United States. Optimal detection of canine intestinal parasitism was achieved by combining CF and CAI. Canine intestinal parasites are common across the United States, and dog health can be enhanced by regular testing of fecal samples and routine administration of medications effective against the most common infections.