Identification of immunodominant antigens in canine leptospirosis by Multi-Antigen Print ImmunoAssay (MAPIA).

BACKGROUND: The microscopic agglutination test (MAT), the standard method for serological diagnosis of leptospirosis, may present limitations regarding its sensitivity. Current studies suggest that Leptospira immunoglobulin-like (Lig) proteins and LipL32 are of particular interest as serodiagnostic markers since they are present only in pathogenic species of the Leptospira genus. The purpose of this study was to identify leptospiral immunodominant proteins that are recognized by canine sera from diseased dogs. RESULTS: A total of 109 dogs were studied, including seroreactive dogs (MAT ≥800) and dogs with no seroreactivity detectable by MAT. Eight recombinant fragments (31-70 kDa) of pathogenic Leptospira were tested for their use as diagnostic markers for canine leptospirosis using the Multi-antigen Print Immunoassay (MAPIA) platform: LigB [582-947aa] from L. interrogans serovar Pomona, L. interrogans serovar Copenhageni and L. kirschneri serovar Gryppotyphosa, LigB [131-649aa] from L. interrogans serovar Copenhageni, L. interrogans serovar Canicola and L. kirschneri serovar Gryppotyphosa, LigA [625-1224aa] L. interrogans serovar Copenhageni and LipL32 from L. interrogans serovar Copenhageni. The data were analyzed and ROC curves were generated. Altogether, LigB [131-649aa] L. interrogans Canicola, LigB [131-649aa] L. kirschneri Gryppotyphosa and LipL32 L. interrogans Copenhageni showed best accuracy (AUC = 0.826 to 0.869), with 70% specificity and sensitivity ranging from 89% to 95%. CONCLUSIONS: These results reinforce their potential as diagnostic candidates for the development of new methods for the serological diagnosis of canine leptospirosis.

Laboratorial diagnosis of animal leptospirosis

Leptospirosis is the most widespread zoonosis in the world, but it is more prevalent in tropical than in temperate regions. Its etiologic agent, pathogenic Leptospira sp., penetrates the animal skin through cuts or abrasions, external mucosa (such as the conjunctiva). Clinical signs are variable and unspecific, particularly in animals, mainly in chronic infections, which are often asymptomatic. For an effective control of an infectious disease it is essential a diagnostic test that have high sensitivity, specificity and practicality. In leptospirosis, misdiagnosis is frequent, what can lead to erroneous treatment in cases of acute disease and to the maintenance of the agent in herds, what could determine considering losses. Noteworthy that the natural course of the disease influences directly on which diagnostic test should be chosen, as well as the type of clinical sample that should be collected. The laboratory diagnosis of leptospirosis is challenging, where there is not a highly sensitive and specific test for a reliable diagnosis in animals. This review presents advantages and disadvantages of the current laboratory methods for animal leptospirosis diagnosis considering the differences between affected species and the disease pathogenicity.