Detection of antibodies against Leptospira serovars via microscopic agglutination tests in dogs in the United States, 2000-2007.
ABSTRACT To use results of microscopic agglutination tests (MATs) conducted at a commercial veterinary diagnostic laboratory to determine temporal and demographic distributions of positive serologic test results for leptospirosis in dogs and identify correlations among results for various Leptospira serovars.
MAT results for 33,119 canine serum samples submitted to a commercial veterinary diagnostic laboratory from 2000 through 2007.
Electronic records of MAT results for dogs were obtained from a veterinary diagnostic laboratory. Seropositivity for antibodies against Leptospira serovars was determined by use of a cutoff titer of >or=1:1,600 to reduce the possible impact of postvaccinal antibodies on results. Correlations between results for all possible pairs of serovars were calculated by ordinal ranking of positive (>or=1:100) antibody titer results.
2,680 samples (8.1%; 95% confidence interval [CI], 7.8% to 8.4%) were seropositive for antibodies against Leptospira serovars. The highest percentage of positive MAT results was for the year 2007 (10.2%; 95% CI, 9.5% to 10.9%) and for the months of November and December during the study period. Antibodies were most common against serovars Autumnalis, Grippotyphosa, Pomona, and Bratislava. Seroprevalence of leptospirosis was lowest for dogs>10 years of age but was similar across other age strata.
Leptospirosis can affect dogs of small and large breeds and various ages. Although an increase in proportions of positive MAT results was evident in the fall, monthly and annual variations suggested potential exposure in all months. Because of the limitations of MAT results and the limited number of serovars used in the test, bacterial culture should be used to identify infective Leptospira serovars.
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ABSTRACT: Leptospirosis is a re-emerging disease of dogs in the United States (U.S.). This paper reports the findings of a retrospective study conducted to determine if seroreactivity to Leptospira microscopic agglutination test (MAT) among dogs in the U.S. clustered in space and time. The study utilized canine sera submitted to a commercial laboratory for leptospiral MAT from January 2000 through December 2007. There were 31,869 serum samples submitted by veterinarians from 3156 zip code locations across the U.S. Results of MAT were considered positive at titers of > or = 1:1600. Spatial and spatial-temporal scan statistics were used to identify statistically significant clusters of seroreactivity to Leptospira (overall and individual serovars) using recorded test request dates and locations of the centroid of the zip code reported for each serum sample. There were 2469 positive MAT results with a titer > or = 1:1600 to at least one of seven Leptospira serovars. Two relevant spatial clusters of 26.3 and 246.5 km radius were identified (P=0.001). The primary cluster was located in the northeastern part of Illinois including Chicago and surrounding areas (232 [14.4%] of 1612 MAT positive; RR=1.95). The secondary cluster covered the central part of Texas (292 [12.62%] of 2314 MAT positive; RR=1.71). Eight space-time clusters of overall MAT positivity were identified (29-335 km radius; P=0.001-0.048 and RR=3.98-24.69) that covered different geographic locations for different time points. Spatial and space-time clusters for individual serovars were also identified for six serovars: eight each of Grippotyphosa and Pomona, seven of Bratislava, five of Autumnalis, and three each of Icterohaemorrhagiae and Canicola. In conclusion Leptospira seropositivity in dogs tended to have distinctive clusters in space and space-time. Most of the space-time clusters of overall Leptospira MAT seropositivity were associated with cluster events for individual serovars. Further investigation is warranted to explain individual serovar clusters detected in this study, as a complex interaction of incidental host, environment and reservoir host may be responsible for the occurrence of these serovar clusters.Preventive Veterinary Medicine 08/2010; 96(1-2):122-31. DOI:10.1016/j.prevetmed.2010.05.017 · 2.51 Impact Factor
Article: Acute Kidney Injury in Dogs and Cats[Show abstract] [Hide abstract]
ABSTRACT: The term acute kidney injury (AKI) has replaced the historical term acute renal failure for renal damage occurring over a short period of time (hours to days) because it is thought to better describe the pathophysiologic changes and duration of the different phases of injury. There are many potential causes of AKI in dogs and cats, and the prognosis has been shown to vary with the cause as well as with therapy. This article reviews current concepts of the pathophysiology, causes, clinical presentation, approach to diagnosis, and medical management of AKI in dogs and cats.Veterinary Clinics of North America Small Animal Practice 01/2011; 41(1):1-14. DOI:10.1016/j.cvsm.2010.09.003 · 1.04 Impact Factor
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ABSTRACT: The microscopic agglutination test (MAT) is commonly used for the diagnosis of canine leptospirosis. In dogs it is sometimes suggested that the serogroup with the highest MAT titer is the infecting serogroup; however, this is not true in humans with confirmed leptospirosis. We sought to investigate the value of MAT results in predicting the infecting serogroup by comparing results across several laboratories and within individual dogs over time. To examine the variability in MAT results across different laboratories in dogs recently vaccinated against leptospirosis, and in dogs with clinical leptospirosis, and to investigate variability over time in MAT results in individual dogs with leptospirosis. Eighteen dogs from a research colony, 9 of which had been vaccinated against leptospirosis, and 17 dogs clinically diagnosed with leptospirosis. Serum samples were submitted to up to 5 veterinary diagnostic laboratories for MAT titers from each dog on at least 1 occasion. MAT results also were followed over time in 6 dogs diagnosed with leptospirosis. MAT results were discordant across different laboratories in dogs recently vaccinated against leptospirosis and in dogs with clinical leptospirosis. MAT results varied over time in individual dogs with the disease. The MAT is a valuable test for the diagnosis of leptospirosis in dogs, but it is unlikely that test results can be used to predict the infecting serogroup. Laboratories offering the MAT should consider participation in a proficiency scheme.Journal of Veterinary Internal Medicine 03/2011; 25(3):426-32. DOI:10.1111/j.1939-1676.2011.0704.x · 2.22 Impact Factor