Leptospirosis Statistics in the Pacific Northwest
January through September 15, 2018
This report summarizes leptospirosis titer testing submitted through Phoenix Lab using the microscopic agglutination test (MAT) at the Washington Animal Disease Diagnostic Laboratory (WADDL) at Washington State University. We also report on the result of Leptospira PCR (polymerase chain reaction) testing on urine and whole blood through the Michigan State University Veterinary Diagnostic Laboratory.
A total of 111 samples were submitted for leptospirosis titers – from 98 dogs and four horses. Nine paired samples were submitted and thus there were 102 animals for which individual samples were submitted for testing.
There were five samples consistent with current exposure to leptospirosis, all based on the results of a single titer. One case was a horse, the remaining four were dogs. One of the dogs was a two year old, but the majority were middle age to slightly older. All were medium to large breed dogs. History of illness and vaccination status were unknown in the animals.
The youngest dog had the highest titer to L. pomona, one dog had a high titer to L. grippotyphosa and a rising titer to L. autumnalis, one dog had the highest titer to L. icterohaemorrhagica, and the last dog had the highest titer to L. bratislava. The horse had equally high titers to L. bratislava and L. pomona.
Positive results in dogs came from the months of January, March, May and September. The horse tested positive in May. The clinics of record for the dogs with titers consistent with current exposure were located in Spokane, Bain Bridge Island, Lynnwood and Wenatchee. The horse was seen at a clinic in Buckley.
For comparison, 161 to 189 animals/year were tested for leptospirosis from 2012 through 2017. The number of animals having MAT titers consistent with current exposure was 17 in both 2012 and 2013, 29 in 2014, 20 in 2015, 19 in 2016 and 6 in 2017.
Eleven patients had samples submitted for Leptospira PCR testing. Five samples were whole blood, four were done on urine and two on both. Three of these patients also had testing with leptospirosis serology. All Leptospira PCR testing was negative. Serology done on those patients also did not support concurrent exposure to leptospirosis.
Testing for Leptospirosis: (see companion handout on testing)
Leptospirosis is a reportable disease to the Washington State Department of Health. Diagnostic laboratories and attending veterinarians are required to report results consistent with current exposure.