Comparison of the prevalence of Toxocara egg shedding by pet cats and dogs in the U.S.A., 2011-2014.

County based prevalence maps were produced using the annual data from the years 2011 through 2014 of the prevalence of Toxocara egg shedding in more than 500,000 pet cat and 2.5 million pet dog fecal samples submitted to centralized testing laboratories. Fecal examination results were obtained at these centers through examination of the samples by centrifugal floatation and microscopy, and were previously reported as annual data on the Companion Animal Parasite Council (CAPC) website. The county maps were generated with mapping and spatial analysis software, and statistical comparisons made using two data analysis packages. The national prevalence of eggs in the feces of pet cats and dogs during this four-year period was 4.6-5.1% and 1.8-2.0%, respectively. Thus, Toxocara cati and Toxocara canis remain considerably prevalent and geographically distributed in our pet populations in spite of the availability of effective and safe treatments. Furthermore, pet cats are found to be shedding Toxocara eggs more commonly than pet dogs. This trend was especially evident in the Northeastern, Midwestern and Southern regions of the U.S.A. when prevalence rates of fecal shedding for cats and dogs in different regions were compared using general linear modeling. In spite of this, fecal endoparasite examination tests for cats comprise only 16-17.6% of the total number of samples annually requested in this data set. This high prevalence of egg shedding poses a significant public health risk, as emphasized by the recent naming of toxocariasis to the list of the top five neglected parasitic infections of Americans. Therefore, it is essential for veterinarians to continue to stress to owners the importance of routine anthelmintic treatment for pets of all ages, and to place greater emphasis on the importance of testing and treatment of parasitic infections in cats.