Prevalence of serum antibodies against six Leptospira serovars in healthy dogs.
OBJECTIVE
To determine the prevalence of antibodies against 6 Leptospira serovars and determine risk factors associated with positive Leptospira titers in healthy client-owned dogs in Michigan.


METHODS
Cross-sectional study.


METHODS
1,241 healthy dogs at least 4 months of age.


METHODS
Dogs were examined by veterinarians at private practices. Vaccinated and unvaccinated dogs were enrolled in the study, which occurred prior to the availability of a 4-serovar (Canicola, Grippotyphosa, Icterohaemorrhagiae, and Pomona) Leptospira vaccine. Sera were tested by use of the microscopic agglutination test to determine antibody titers against Leptospira serovars Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae, and Pomona. A questionnaire was used to collect demographic information about each dog to identify risk factors associated with seropositive status.


RESULTS
309 of 1,241 (24.9%) dogs had antibody titers against at least 1 of the 6 Leptospira serovars, which suggested exposure to Leptospira spp. Prevalence of antibodies was highest to serovar Grippotyphosa, followed by Bratislava, Canicola, Icterohaemorrhagiae, and Pomona. Age, travel outside Michigan, exercise outside fenced yards, and exposure to livestock and wildlife were significant risk factors for positive titers.


CONCLUSIONS
Among healthy dogs from the lower peninsula of Michigan, > 20% have antibodies against leptospiral serovars historically considered uncommon but more recently incriminated as causing clinical canine leptospirosis. Wildlife and livestock may be of increasing importance as reservoirs for canine leptospirosis as urbanization continues to occur. Expanded vaccination strategies may partially mitigate these trends.
Stokes
Jennifer E
JE
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824-1314, USA.
Kaneene
John B
JB
Schall
William D
WD
Kruger
John M
JM
Miller
RoseAnn
R
Kaiser
Lana
L
Bolin
Carole A
CA
D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D000835:Animals, Wild; D000907:Antibodies, Bacterial / Q000097:blood*; D001428:Bacterial Vaccines / Q000276:immunology*; D003430:Cross-Sectional Studies; D004283:Dog Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D004285:Dogs; D005260:Female; D007919:Leptospira / Q000145:classification / Q000276:immunology*; D007922:Leptospirosis / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D008297:Male; D008824:Michigan / Q000453:epidemiology; D010802:Phylogeny; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D014195:Travel
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines