Prevalence of Feline Helminth Infections

Common helminth infections in cats include Toxocara cati, Ancylostoma tubaeforme, Dipylidium caninum, and Taeania taeniaeformis. Fecal flotation is commonly used to diagnose these infections in clinical practice. This study compared the results of passive and centrifugal fecal flotation with parasite recovery at the time of necropsy from the intestinal tract of humanely euthanized adult cats (n = 116) from an animal shelter. External examination revealed that 85/116 (73.3%) of cats had fleas (all fleas recovered were Ctenocephalides felis). Helminths were found in 78/116 (67.2%) of cats on gross examination of the GI tract. Passive and centrifugal fecal flotation identified 68.8% and 77.1% of T cati infections and 25% and 100% of A tubaeforme infections, respectively. Sixty-three cats were found to have cestode infections on gross examination of the intestinal tract, but proglottids were found in only 12 of these cats on external examination. Passive and centrifugal fecal flotation identified 4.8% and 12.7% of cestode infections, respectively, and were consistent with Taenia spp. The authors conclude that ascarids and cestodes are still common parasites in cats and that current diagnostic testing is unlikely to reveal all infections in cats.  

The 67% prevalence of helminth infections found in cats in this study is alarming. Obviously, because of a higher prevalence of predation and flea infestation, this shelter cat population is at a higher risk for infection then most client-owned cats. However, undiagnosed feline intestinal parasite infection, which can cause intestinal disease and possibly lung lesions, may be far more prevalent in our practices than previously thought. As shown here, even with superior fecal examination techniques, helminth infections may be missed. It is well-established that using a swing head centrifugation technique consistently recovers more eggs than flotation techniques alone. The flotation solution must have a higher specific gravity than the parasite egg or oocyst. Most flotation solutions (eg, Fecasol, vetoquinolusa.com; sodium nitrate solution), have a specific gravity (SG) of 1.020. Although Toxocara cati eggs (SG 1.100) are easily found, Taenia (SG 1.225), and Physaloptera spp (SG 1.237) are obviously heavier and would be easily missed with this technique. Routine preventative broad-spectrum deworming is indicated in all cats, especially those with access to the outdoors.—Elizabeth Alvarez, DVM, DABVP