title: Risk factors associated with failure of heartworm prophylaxis among members of a national hunting dog club.
abstract: OBJECTIVE
  To identify practices associated with failure of heartworm prophylaxis among dog and kennel owners and dog trainers.
  
  
  METHODS
  Online survey and mail-in questionnaire. Sample-708 members of a national hunting dog club.
  
  
  METHODS
  Heartworm prevention practices used by respondents that reported failure of prophylaxis were compared with practices used by respondents that reported success.
  
  
  RESULTS
  Univariate analyses indicated failure of heartworm prophylaxis was inversely related to the number of dogs under a respondent's care. Year-round prophylactic practice was not significantly associated with reduced odds of failure, and efforts to control exposure to mosquitoes were similar among the comparison groups. Respondents reporting prophylaxis failure were more likely to test for heartworm infection ≥ 1 time/y, compared with those reporting success. In a multivariable analysis, residence south of the Virginia-North Carolina state line (ie, the 37th geographic parallel), testing for heartworm infection < once a year when the test was administered prior to April 1, and keeping dogs outdoors for longer periods at dusk, at dawn, or after dark were associated with increased odds of prophylaxis failure.
  
  
  CONCLUSIONS
  Veterinarians should stress the importance of annual heartworm testing 6 to 7 months after the last possible date of exposure to heartworm, regardless of whether a dog receives prophylactic treatment year-round. Reducing the number of hours dogs spend outdoors at dusk, at dawn, or after dark may reduce the odds of heartworm disease even when dogs are given preventive treatment.
authors.affiliation: Department of Comparative Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Barton W
authors.initials: BW
authors.lastname: Rohrbach
authors.forename: Agricola
authors.initials: A
authors.lastname: Odoi
authors.forename: Sharon
authors.initials: S
authors.lastname: Patton
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000627:therapeutic use*; D009033:Culicidae; D003625:Data Collection; D004184:Dirofilariasis / Q000517:prevention & control*; D004283:Dog Diseases / Q000517:prevention & control*; D004285:Dogs; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000871:Anthelmintics