Pathogenic Leptospira strains identified in Uruguay cattle

Leptospirosis is a neglected zoonosis with worldwide distribution. Among many other mammalian species, Leptospira infects cattle, eliciting acute signs in calves, and chronic disease in adult animals often leading to abortions. In South America, beef and dairy export are leading sources of national income. Despite the importance of bovine health, food safety, and bovine-related dissemination of leptospirosis to humans, limited information is available as to the identity of Leptospira species and serovars infecting cattle in Uruguay and the South American subcontinent.

To determine the identity of the Leptospira variants that infect cattle in Uruguay, and whether they are a potential risk for humans, a multicentric consortium was created involving the Institut Pasteur of Montevideo, the Faculty of Medicine (UdelaR), the Agricultural Research National Institute (INIA) and the Ministry of Livestock (MGAP). This multidisciplinary team sampled urine and blood from 963 cattle at 48 beef and dairy farms around Uruguay. Additionally, they collected the urine and kidneys from 577 animals from 22 slaughterhouses. Each sample was tested for the presence of Leptospira and, if present, for the exact strain.

The researchers report in PLOS Neglected Tropical Diseases that approximately 20% of all cattle sampled were shedding pathogenic Leptospira in their urine, representing a large public health risk. 40 different strains of the bacteria were isolated, uncovering an unexpectedly large variation. The bacteria identified included three rare isolates undetected by normal tests, and two serotypes of the bacteria that matched exactly with those previously isolated from leptospirosis patients.

“This report of local Leptospira strains shall improve diagnostic tools and the understanding of leptospirosis epidemiology in South America,” the researchers say. “These strains could also be used as new components within bacterin vaccines to protect against the pathogenic Leptospira strains that are actually circulating, a direct measure to reduce the risk of human leptospirosis.”

Article: Isolation of pathogenic Leptospira strains from naturally infected cattle in Uruguay reveals high serovar diversity, and uncovers a relevant risk for human leptospirosis by Leticia Zarantonelli, Alejandra Suanes, Paulina Meny, Florencia Buroni, Cecilia Nieves, Ximena Salaberry, Carolina Briano, Natalia Ashfield, Caroline Da Silva Silveira, Fernando Dutra, Cristina Easton, Martin Fraga, Federico Giannitti, Camila Hamond, Melissa Macías-Rioseco, Clara Menéndez, Alberto Mortola, Mathieu Picardeau, Jair Quintero, Cristina Ríos, Víctor Rodríguez, Agustín Romero, Gustavo Varela, Rodolfo Rivero, Felipe Schelotto, Franklin Riet-Correa and Alejandro Buschiazzo, on behalf of the Grupo de Trabajo Interinstitucional de Leptospirosis Consortium, published in PLoS Neglected Tropical Diseases (2018) 12(9): e0006694, doi: 10.1371/journal.pntd.0006694