*3.1.1. Leptospira spp.*

Spirochetes of the Leptospira genus are the agents causing leptospirosis, a disease mainly characterized by reproductive disorders. In serological study conducted in Brazil, Favero et al. [20] (2002) observed that the most prevalent serovars associated with Leptospirosis are: pomona, icterohaemorrhagiae, copenhageni and tarassovi. The disease has worldwide dis‐ tribution and leads to infertility of the animals [21].

The main route for elimination of the Leptospires is through urinary system [22]. However, they may be present in the infected animals´ semen, as causing the infection of the female and can lead to reproductive complications during the bacteremia phase, inclusive abortion [23]. The bacteria can persist in the kidneys and reproductive organs of both males and fe‐ males, therefore facilitating the dissemination of the disease in herd, requiring an early diag‐ nosis of the disease.

To fill out this need, the tests for antibody detection by serology are effective. However, for serotyping the Leptospires is necessary to consider other diagnostic techniques. Attention should be given to the vaccinated seropositivos animals, since the antibodies are likely due to vaccinal reaction. For detection of the agent, molecular tests can be performed by PCR and immunoassay such as the direct immunofluorescence [24, 25].

In the case of a positive diagnosis, even with few affected animals, the control must be taken by adopting the following criteria: management, fight against rodents, vaccination and drug treatment in order to prevent the dissemination of the disease in the herd. Con‐ sidering that Leptospira are sensitive to a wide variety of antimicrobial agents, the treat‐ ment associated with vaccination and sanitary measures provides an effective control of the disease [26].
