text: Prevalence of Baylisascaris in domestic dog coprological examinations in the United States, 2013-2016.
  Dogs are alternative definitive hosts for Baylisascaris procyonis, the raccoon roundworm, but broad-scale prevalence and distribution of canine cases is not known. Based on a large dataset from nationwide reference laboratories, Baylisascaris spp. eggs were detected in 504/9,487,672 (0.005%) canine fecal samples. While many of the positive dog samples originated in areas of known high B. procyonis prevalence in raccoons, positives were also detected in 9 new states. Young dogs, large breeds, and certain regions had higher prevalence. Although overall prevalence was low, and some infections may be spurious, these results demonstrate that dogs may shed Baylisascaris spp. into domestic environments. Routine parasitic testing, rigorous preventive use, and restrictions on coprophagy should be encouraged to reduce risk of human or animal exposure to infectious eggs.