Prevalence of and risk factors for leptospirosis among dogs in the United States and Canada: 677 cases (1970-1998).
OBJECTIVE
To determine whether there was a temporal trend in prevalence of leptospirosis among dogs in the United States and Canada and to determine whether age, sex, and breed were risk factors for the disease.


METHODS
Retrospective study.


METHODS
1,819,792 dogs examined at 22 veterinary teaching hospitals between 1970 and 1998.


METHODS
The Veterinary Medical Data Base was searched for records of dogs in which a diagnosis of leptospirosis was made, and hospital prevalence was calculated. Logistic regression was used to examine the association between leptospirosis and age, sex, and breed.


RESULTS
677 dogs with leptospirosis were identified. Thus, hospital prevalence was 37 cases/100,000 dogs examined. A significant increase in leptospirosis prevalence between 1983 and 1998 was identified. Male dogs were at significantly greater risk of leptospirosis than were female dogs; dogs between 4 and 6.9 years old and between 7 and 10 years old were at significantly greater risk than dogs < 1 year old; and herding dogs, hounds, working dogs, and mixed-breed dogs were at significantly greater risk than companion dogs.


CONCLUSIONS
The prevalence of leptospirosis among dogs examined at veterinary teaching hospitals in the United States and Canada has increased significantly since 1983. Male dogs of working and herding breeds were at greater risk.
Ward
Michael P
MP
Department of Veterinary Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907-1243, USA.
Glickman
Lawrence T
LT
Guptill
Lynn E
LE
D000367:Age Factors; D000818:Animals; D001947:Breeding; D002170:Canada / Q000453:epidemiology; D016001:Confidence Intervals; D004283:Dog Diseases / Q000453:epidemiology*; D004285:Dogs; D005260:Female; D006762:Hospitals, Animal / Q000706:statistics & numerical data; D007922:Leptospirosis / Q000453:epidemiology / Q000662:veterinary*; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014481:United States / Q000453:epidemiology