Prevalence of intestinal nematode parasitism among pet dogs in the United States (2003-2006).

Objective: To estimate prevalence of intestinal nematode parasitism among pet dogs in the United States and characterize risk factors for infection.
Design: Retrospective period prevalence survey.
Animals: 1,213,061 dogs examined at 547 private veterinary hospitals in 44 states from January 1, 2003, through December 31, 2006.
Procedures: Data were obtained from electronic medical records of all dogs that had at least 1 fecal flotation test. Risk factors for intestinal nematode parasitism were identified by means of multivariable logistic regression analysis.
Results: 2,785,248 fecal flotation tests were performed during the study period. When results for only the first test in each dog were considered, prevalences of Toxocara, Ancylostoma, and Trichuris parasitism were 5.04%, 4.50%, and 0.81%, respectively. Dogs < 0.5 years old had higher odds of Toxocara and Ancylostoma parasitism, compared with dogs > 5.0 years old; sexually intact male and female dogs had higher odds of parasitism, compared with spayed female dogs; toy dogs had lower odds of parasitism, compared with dogs in other breed groups; and dogs living in the mountain region had lower odds of parasitism, compared with dogs living in other regions.
Conclusions and Clinical Relevance: Results suggested that age, body weight, sex, breed, and geographic region were risk factors for intestinal nematode parasitism among pet dogs in the United States.