A 3-year retrospective analysis of canine intestinal parasites: fecal testing positivity by age, U.S. geographical region and reason for veterinary visit

Abstract

Background Canine life stage is a key factor in parasite prevalence as clinical signs associated with parasitism are more common in pups. In adult dogs, health status and geographical region may also play a role in parasite prevalence. The purpose of this study was to evaluate fecal test results using zinc sulfate flotation by centrifugation combined with fecal antigen testing for hookworms (Ancylostoma spp. Uncinaria stenocephala), ascarids (Toxocara canis, Toxascaris spp., Baylisascaris spp.) and whipworms (Trichuris vulpis) sorted by age, geographical region and veterinary visit type. Methods A retrospective sample of intestinal parasite panels submitted to IDEXX Laboratories from 1,626,104 individual dogs were selected from the continental USA from 1 January 2017 to 31 December 2019. These data contain results from fecal exams performed using zinc sulfate flotation by centrifugation paired with coproantigen immunoassay results for hookworms, ascarids, whipworms and Giardia (Fecal Dx® with Giardia coproantigen immunoassay plate). For paired testing, if either the coproantigen assay or flotation test was positive, the sample was considered to be positive. Data were summarized by age category, U.S. Census Bureau geographical region (Northeast, South, Midwest, West) and veterinary visit type. Visit types were subdivided into Wellness Visits and Other Clinical Visits in which a fecal sample was submitted. Results In dogs presenting for either Wellness Visits or Other Clinical Visits in which Giardia testing was included, Giardia had the highest positivity (combined results for microscopy and coproantigen: 12.2 and 10.8%, respectively), followed by hookworms (combined microscopy and coproantigen: 4.1 and 4.2%, respectively), ascarids (combined microscopy and coproantigen: 2.5 and 1.7%, respectively) and whipworms (combined microscopy and coproantigen: 1.1 and 1.4%, respectively). When all test results were pooled together, pups aged 2–6 months were observed to have the highest proportion of positive results by either microscopy or coproantigen immunoassay regardless of clinical visit type. Parasite positivity varied by geographical region. Regardless of visit type, age or geographical region, the coproantigen method was observed to find a higher proportion of positive test results than microscopy in Giardia, ascarids, hookworms and whipworms. Conclusions The Fecal Dx® coproantigen immunoassay combined with the zinc sulfate flotation by centrifugation method uncovers a higher number of positive hookworm, ascarid and whipworm infections than zinc sulfate flotation alone in both pups and adult dogs across all geographical regions of the USA regardless of visit type.

Endoparasitism of Golden Retrievers: Prevalence, risk factors, and associated clinicopathologic changes

“…Within the analyzed group of young Golden Retrievers, we found the overall prevalence of endoparasite infection to be 6.99%. This is lower than many previously reported prevalence studies, which report up to 48.3% prevalence for any intestinal parasite [7]. Multiple statistically significant, albeit modest, clinicopathologic changes were identified between patients who were positive via fecal flotation for at least one pathogenic parasite when compared to patients with no evidence of endoparasitism.…”

“…Additionally, the study population was limited to patients under 3 years of age. This may have increased the overall prevalence as compared to a population that included all ages of dogs, because previous studies have shown increased prevalence of most parasite infections in younger dogs [2][3][4][5][6][7][8][9][10]. This choice was intentional to allow for comparison across a single time point as well as minimize the influence of concurrent disease often associated with an older population.…”

“…Accurate knowledge of parasite prevalence and relevant risk factors are crucial for prompt diagnosis and treatment, as well as the design of optimal protocols for parasite control and owner education. Prevalence studies and assessment of risk factors for intestinal endoparasitism have been performed across various populations and geographical locations [2][3][4][5][6][7][8][9][10].…”

Canine nematode and Giardia spp. infections in dogs in Edmonton, Alberta, the “CANIDA” study

“…in 5.8% of samples. This is comparable (4%) with a large national survey in the US (Little et al) but lower than that reported in other studies using similar techniques reported by Stafford et al and Sweet et al [ 2 , 3 , 8 ]. Reliance on flotation alone, Giardia spp.…”

“…The Companion Animal Parasite Council (CAPC) states that combining fecal flotation by centrifugation with coproantigen testing may aid in the identification of intestinal parasites where few to no eggs are recovered, for instance during the prepatent period or in the case of single sex infections. However, widespread adoption of regular intestinal parasite screening protocols remains a challenge, despite studies demonstrating that intestinal parasite infections are a common finding in dogs in the USA [ 2 , 3 ].…”