Leptospirosis

Leptospirosis

Leptospirosis is a worldwide zoonotic disease of domestic animals and wildlife. It is caused by a spirochete bacteria classified under the Leptospira , of which there are ~17 species. The taxonomy of the genus is confusing, with a number of species, including interrogans (sensu stricto), kirschneri , and santarosai. Serovars, as defined by agglutination cross-absorption, are the primary grouping below the species designation. This can add even greater confusion, as some serovars are grouped under more than one species. The term Leptospira interrogans (sensu lato) is used to describe the broad group of pathogenic leptospires associated with animal hosts.


Dogs are considered the reservoir host for serovar canicola . Based on studies that focused on urban populations of dogs, serovars canicola and icterohemorrhagiae were considered the most prevalent serovars infecting dogs. Studies that have included more rural and suburban populations of dogs document the predominance of serovars of grippotyphosa and pomona as causative agents of canine leptospirosis. Other serovars, particularly bratislava , have also been implicated. A variety of factors, such as increased exposure to raccoons and opossums in suburban and rural areas, communities encroaching on wildlife habitats, and poor farming practices, may explain the rise of previously low-prevalence serovars. Rodents continue to play an important role as reservoirs in urban settings.

Diagnosis:

Serology is the most useful and frequently used diagnostic test for dogs. Acute and convalescent titers may be necessary to confirm a diagnosis. Other diagnostic tests, such as darkfield microscopy, fluorescent antibody, PCR, culture, and histopathology are less frequently used antemortem. Demonstration of leptospires in tissues with silver staining or fluorescent antibody testing are preferred postmortem.