Leptospirosis infections, caused by Leptospira bacteria, occur in people and animals around the world, but different strains of the bacteria may vary in their ability to cause disease and to jump between species. Now, researchers reporting in PLOS Neglected Tropical Diseases have for the first time described the characteristics of the Leptospira variants that infect cattle in Uruguay.
Leptospirosis is most often transmitted to humans through contaminated water, and outbreaks are seen in tropical and subtropical areas after large amounts of rain or floods. Water can initially be contaminated through the urine of infected animals, including rats, cattle, horses, sheep, pigs and dogs. In Uruguay, beef and dairy exports are leading sources of national income.
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 found that 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."
Peer-reviewed / Observational Study / Animals
In your coverage please use this URL to provide access to the freely available article in PLOS Neglected Tropical Diseases: http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0006694
Citation: Zarantonelli L, Suanes A, Meny P, Buroni F, Nieves C, et al. (2018) Isolation of pathogenic Leptospira strains from naturally infected cattle in Uruguay reveals high serovar diversity, and uncovers a relevant risk for human leptospirosis. PLOS Neglected Tropical Diseases 12(9): e0006694. https://doi.org/10.1371/journal.pntd.0006694
Funding: This work was supported by grants from the Agencia Nacional de Investigacion e Innovación (ANII Uruguay) #ALI_1_2014_1_4982 (AB), #FSA_1_2013_1_12557 (AB) and #FSA_X_2014_1_105696 (FR-C). Partial support was also obtained through grants from Institut Pasteur Paris (PTR Program) #PTR30-17, Ministerio de Industria, Energia y Mineria (MIEM, Industrial Funds program) #2016-8-2-002671, and FOCEM (MERCOSUR Structural Convergence Fund) #COF03/11; and through institutional funds from Instituto Nacional de Investigacion Agropecuaria (INIA), Ministerio de Ganaderia, Agricultura y Pesca (MGAP), Instituto de Higiene (IH, UdelaR University Medical School) and Institut Pasteur de Montevideo (IPMontevideo). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: Alejandro Buschiazzo is an Associate Editor of PLOS Neglected Tropical Diseases. Co-author Mathieu Picardeau is a Deputy Editor of PLOS Neglected Tropical Diseases.
PLoS Neglected Tropical Diseases