Prevalence of parasitism in client-owned dogs determined by fecal examinations in the Pacific northwest, United States, in 2021–2023

It is important to continuously monitor the prevalence of parasitic infections in client-owned dogs. However, very limited information is available for the Pacific Northwest (PNW) region of the United States (US). Our main study objective was to determine the prevalence of parasitism observed in the feces of client-owned dogs in the PNW, US. Additionally, the prevalence of parasitic infections was statistically compared by sex, age, and seasonality. Results of all the fecal examinations with various methodologies performed at Zoetis Reference Laboratories in Mukilteo, Washington, from February 1, 2021 to December 31, 2023, were examined. A total of 82,603 fecal samples tested were included in this study. Most samples (88.47 %; 73,076/82,603) did not contain any parasites or eggs. A single parasite was identified in 8322 (10.07 %) samples, whereas multiple parasites were seen in 1205 (1.46 %) samples. The most commonly diagnosed parasite was Giardia (6.77 %, 5596/82,603), followed by Cystoisospora (1.86 %, 1535/82,603), Toxocara canis (1.85 %, 1526/82,603), Ancylostoma (0.82 %, 679/82,603), Cryptosporidium (0.76 %, 629/82,603), Trichuris vulpis (0.33 %, 271/82,603), Toxascaris leonina (0.22 %, 178/82,603), taeniids (0.15 %, 122/82,603), Sarcocystis (0.12 %, 84/82,603), Nanophyetus salmincola (0.09 %, 74/82,603), Dipylidium caninum (0.07 %, 60/82,603), Neospora-like coccidia (0.06 %, 47/82,603), Capillaria (0.03 %, 27/82,603), Demodex (0.02 %; 17/82,603), Baylisascaris (0.01 %, 9/82,603), Spirometra (0.01 %, 7/82,603), and Otodectes cynotis (0.01 %; 5/82,603). Additionally, Strongyloides stercoralis larvae were found in four cases, and Alaria eggs, Cheyletiella mites, and possible Oslerus/Filaroides larvae were identified in one case. This study indicates the importance of routine fecal examinations and application of broad-spectrum anthelmintics to dogs in the PNW region.