The aim of the present study was to consider the wide usage of urinary PCR as an increasingly useful tool for an accurate diagnosis of leptospirosis in livestock. A total of 512 adult animals (300 cattle, 138 horses, 59 goats and 15 pigs), from herds/flocks with reproductive problems in Rio de Janeiro, Brazil was studied by serology and urinary PCR. From the 512 serum samples tested, 223 (43.5 %) were seroreactive (cattle: 45.6 %, horses: 41.3 %, goats: 34%and pigs: 60 %). PCR detected leptospiral DNA in 32.4 % (cattle: 21.6 %, horses: 36.2 %, goats: 77.4 % and pigs: 33.3 %. To our knowledge there is no another study including such a large number of samples (512) from different species, providing a comprehensive analysis of the usage of PCR for detecting leptospiral carriers in livestock. Serological and molecular results were discrepant, regardless the titre, what was an expected outcome. Nevertheless, it is impossible to establish agreement between these tests, since the two methodologies are conducted on different samples (MAT - serum; PCR - urine). Additionally, the MAT is an indirect method and PCR is a direct one. In conclusion, we have demonstrated that urinary PCR should be considered and encouraged as an increasingly useful tool for an accurate diagnosis of leptospirosis in livestock.

The objective of this study was to demonstrate the presence of leptospires in equine urine, as evidence for a potential role of horses in transmission of this organism. Thoroughbred horses (aged 2-5 years, n = 276) from Rio de Janeiro, Brazil, were studied. After a severe storm, the premises of the animals remained flooded for 72 h. Blood samples for serology were collected on days 20 and 35 (day of storm = day 0). On day 20, 132 (47·8%) horses were seroreactive (titre ≥200) and, of these, 23 (31·0%) had increased antibody titres on day 35. Furthermore, 34 urine samples (for PCR and culture) were collected from seroreactive horses on day 35. Copenhageni was the most frequent serovar (88·8% of reactive titres). Although none of the urine samples were culture positive, 12 (35·2%) were PCR positive. This is apparently the first report of evidence of leptospires in urban horses. Furthermore, we suggest that these animals can play a role in the transmission of leptospirosis in urban areas.

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