Detecting Canine Intestinal Parasites: An Update

In the literature

Sweet S, Hegarty E, McCrann DJ, Coyne M, Kincaid D, Szlosek D. A 3-year retrospective analysis of canine intestinal parasites: fecal testing positivity by age, U.S. geographical region and reason for veterinary visit. Parasit Vectors. 2021;14(1):173.

The Research …

Adequate detection and treatment of intestinal parasites is important in both veterinary and human medicine, as several intestinal parasites of dogs can pose a zoonotic risk. Proper detection and identification via fecal examination can be challenging because flotation technique and solution, examiner expertise, age of feces, and presence of pseudoparasites can influence results.

This study* compared parasite recovery from canine feces using centrifugal fecal flotation (zinc sulfate) and coproantigen immunoassay for detection of intestinal parasites. More than 1.9 million tests were performed over a 3-year period. Results were analyzed by age group, US geographic region, and reason for visit (ie, wellness vs other).

When combining flotation and immunoassay results from wellness and other veterinary visits, Giardia spp were detected most frequently (12.2% and 10.8%, respectively); followed by hookworms (4.1% and 4.2%, respectively); roundworms (2.5% and 1.7%, respectively); coccidia (Cystoisospora spp; 1.6% and 1.4%, respectively); whipworms (1.1% and 1.4%, respectively); and tapeworms (0.2% and 0.3%, respectively). During recovery of coccidian oocysts via fecal flotation, Eimeria spp (a pseudoparasite of dogs) were identified more often than Cystoisospora spp.

Dogs 2 to 6 months of age had the highest number of positive results for any intestinal parasite, with Giardia spp, coccidia, and roundworms being most common. The percent of positive tests gradually decreased as age increased. Regardless of geographic region, Giardia spp were most often detected; hookworms were the next most common in all regions except in the west, where roundworms were second most common.

For every parasite detected, coproantigen immunoassay alone detected more positives than fecal flotation alone; furthermore, combined detection using both diagnostics exceeded detection by either diagnostic alone.

… The Takeaways

Key pearls to put into practice:

• Intestinal parasitism is an ongoing problem. Regardless of patient age, testing for intestinal parasites and use of year-round parasite preventives are recommended.

• Using a combination of fecal diagnostic techniques is more likely to lead to an accurate diagnosis.

• Presence of Eimeria spp oocysts in canine fecal samples may be the result of coprophagy, illustrating the importance of obtaining a thorough patient history regarding diet and lifestyle.

*This study was funded by IDEXX Laboratories.