Leptospirosis humana en Argentina: un esquema de análisis, 2014 / Human Leptospirosis in Argentina: An Analysis Scheme, 2014

INTRODUCCIÓN: En general, sólo existen estimaciones sobre el número de casos de leptospirosis en las Américas. La fuente más común son los Ministerios de Salud, tanto nacionales como provinciales, que proporcionan datos útiles sobre tendencias de incidencia de la leptospirosis, identificación de brotes y efectos de intervenciones gubernamentales. OBJETIVOS: Conocer la incidencia de casos de leptospirosis detectados por laboratorio durante 2014 en Argentina y generar un esquema de análisis de bases de datos de diferentes organismos nacionales para que sea repetido y difundido anualmente. MÉTODOS: Se analizaron las bases de datos del Sistema de Vigilancia Laboratorial (SIVILA)y del Instituto Nacional de Enfermedades Respiratorias (INER), teniendo en cuenta los casos notificados en 2014, según la fecha de inicio de síntomas. RESULTADOS: La incidencia de casos confirmados de leptospirosis en 2014 fue de 0,32/100 000 habitantes, mayormente detectados en las provincias de Santa Fe, Buenos Aires y Entre Ríos. Los serogrupos circulantes más prevalentes fueron Icterohaemorrhagiae, Sejroe y Canicola. CONCLUSIONES: Se resalta la utilidad de este tipo de estudios, que incentivan la búsqueda de casos, notificación y vigilancia de la leptospirosis, tanto para mejorar el conocimiento de la incidencia de la enfermedad y su distribución como para orientar las acciones hacia los lugares de mayor riesgo del país.

INTRODUCTION: In general, there are only estimates of the number of cases in the Americas. This data is commonly obtained by both national and provincial Ministries of Health which, despite data limitations, provide useful information on leptospirosis incidence trends, outbreak identification and effects of government interventions. OBJECTIVES: To know the incidence of leptospirosis cases detected by laboratory during 2014 in Argentina, and to generate an analysis scheme of databases from different national organisms to be repeated and diffused annually. METHODS: The SIVILA and INER databases were analyzed, taking into account the cases reported in 2014, according to the date of onset of symptoms. RESULTS: The incidence of confirmed leptospirosis cases in 2014 was 0.32/100 000 persons, mostly detected in Santa Fe, Buenos Aires and Entre Ríos provinces. The most prevalent circulating serogroups were Icterohaemorrhagiae, Sejroe and Canicola. CONCLUSIONS: These studies motivate the suspicion, notification and surveillance of leptospirosis and are useful both to improve the knowledge of the incidence of cases and their distribution, as well as to guide actions towards the most risky places in the country.

Isolation and clinical sample typing of human leptospirosis cases in Argentina.

Leptospira typing is carried out using isolated strains. Because of difficulties in obtaining them, direct identification of infective Leptospira in clinical samples is a high priority. Multilocus sequence typing (MLST) proved highly discriminatory for seven pathogenic species of Leptospira, allowing isolate characterization and robust assignment to species, in addition to phylogenetic evidence for the relatedness between species. In this study we characterized Leptospira strains circulating in Argentina, using typing methods applied to human clinical samples and isolates. Phylogenetic studies based on 16S ribosomal RNA gene sequences enabled typing of 8 isolates (6 Leptospira interrogans, one Leptospira wolffii and one Leptospira broomii) and 58 out of 85 (68.2%) clinical samples (55 L. interrogans, 2 Leptospira meyeri, and one Leptospira kirschneri). MLST results for the L. interrogans isolates indicated that five were probably Canicola serogroup (ST37) and one was probably Icterohaemorrhagiae serogroup (ST17). Eleven clinical samples (21.6%), provided MLST interpretable data: five were probably Pyrogenes serogroup (ST13), four Sejroe (ST20), one Autumnalis (ST22) and one Canicola (ST37). To the best of our knowledge this study is the first report of the use of an MLST typing scheme with seven loci to identify Leptospira directly from clinical samples in Argentina. The use of clinical samples presents the advantage of the possibility of knowing the infecting strain without resorting to isolates. This study also allowed, for the first time, the characterization of isolates of intermediate pathogenicity species (L. wolffii and L. broomii) from symptomatic patients.

[Evaluation of a reduced panel of leptospira strains for microagglutination]. / Evaluación de un panel reducido de cepas de leptospiras para el diagnóstico en humanos por microaglutinación (MAT).

OBJECTIVE: To evaluate if the use of the 19 Leptospira strains panel suggested by the International Leptospirosis Society of World Health Organization for microagglutination allows confirmation of more cases that the 12 strains panel used in Argentina. MATERIALS AND METHODS: Cross-sectional observational study. We studied 441 serum samples corresponding to Argentinean patients with suspected leptospirosis derived during from July to December, 2009 and from January to October, 2013. RESULTS: The same number of positive samples was obtained using the MAT with the 19 or 12 strains. In six cases a serovar of the expanded collection was presumably infecting, but always coagglutinated with strains of the reduced panel. CONCLUSION: In Argentina, the diagnosis of leptospirosis by MAT could be made using the reduced 12 strains panel, obtaining the same result in case detection as using the 19 strains panel. Additional information provided by the use of all strains could be the presumably infecting serogroup.

Evaluación de un panel reducido de cepas de leptospiras para el diagnóstico en humanos por microaglutinación (MAT) / Evaluation of a reduced panel of leptospira strains for microagglutination

Objetivo. Evaluar si el uso del panel de 19 cepas de leptospiras, sugerido por la Sociedad Internacional de Leptospirosis para la microaglutinación (MAT, por sus siglas en inglés), permite mayor confirmación de casos que el de 12 cepas. Material y métodos. Estudio observacional de corte transversal. Se estudiaron 441 muestras de sueros de pacientes de Argentina, derivadas para el diagnóstico de leptospirosis en los periodos de julio de 2009 a diciembre de 2010 y enero a octubre de 2013. Resultados. Se obtuvo el mismo resultado con el panel reducido que con el ampliado. En seis casos resultó presumiblemente infectante algún serovar del panel ampliado, aunque siempre coaglutinando con cepas del reducido. Conclusión. En Argentina, el diagnóstico de leptospirosis por MAT podría continuar realizándose con el panel reducido, lo que reduciría el costo y tiempo de diagnóstico. La información adicional que aportaría el panel ampliado está relacionada con la epidemiología, mediante un mejor conocimiento del serogrupo presumiblemente infectante.

Objective. To evaluate if the use of the 19 Leptospira strains panel suggested by the International Leptospirosis Society of World Health Organization for microagglutination allows confirmation of more cases that the 12 strains panel used in Argentina. Materials and methods. Cross-sectional observational study. We studied 441 serum samples corresponding to Argentinean patients with suspected leptospirosis derived during from July to December, 2009 and from January to October, 2013. Results. The same number of positive samples was obtained using the MAT with the 19 or 12 strains. In six cases a serovar of the expanded collection was presumably infecting, but always coagglutinated with strains of the reduced panel. Conclusion. In Argentina, the diagnosis of leptospirosis by MAT could be made using the reduced 12 strains panel, obtaining the same result in case detection as using the 19 strains panel. Additional information provided by the use of all strains could be the presumably infecting serogroup.

Association of Toll-like receptor 2 Arg753Gln and Toll-like receptor 1 Ile602Ser single-nucleotide polymorphisms with leptospirosis in an Argentine population.

Toll-like receptor 2 (TLR2), a member of the Toll-like receptor family, plays an important role in the recognition of and subsequent immune response activation against leptospirosis in humans. The genetic polymorphism in TLR2 of an arginine to glutamine substitution at residue 753 (Arg753Gln) has been associated with a negative influence on TLR2 function, which may, in turn, determine the innate host response to Leptospira spp. This bacterium signals through TLR2/TLR1 heterodimers in human cells. The aim of the present study was to investigate the Arg753Gln single-nucleotide polymorphism (SNP) of the TLR2 gene, and the isoleucine to serine transversion at position 602 (Ile602Ser) of the TLR1 gene (previously associated with Lyme disease), in leptospirosis patients compared to healthy controls, carrying out a retrospective case/control study. The TLR2 polymorphism adenine (A) allele was observed in 7.3% of leptospirosis patients but was not found in the control group, whereas the guanine (G) allele of the TLR1 polymorphism was found in 63.6% of patients and 41.6% of controls. Susceptibility to leptospirosis disease was increased 10.57-fold for carriers of the TLR2 G/A genotype (P=0.0493) and 3.85-fold for carriers of the TLR1 G/G genotype (P=0.0428). Furthermore, the risk of developing hepatic insufficiency and jaundice was increased 18.86- and 27.60-fold for TLR2 G/A carriers, respectively. Similarly, the risk of developing jaundice was increased 12.67-fold for TLR1 G allele carriers (G/G and T/G genotypes). In conclusion, the present data suggest that the TLR2 Arg753Gln and TLR1 Ile602Ser SNPs influence the risk of developing leptospirosis and its severity.

Diseño y aplicación de una nueva herramienta para la evaluación de la Red Nacional de Laboratorios de Leptospirosis / Design and application of a new tool for the evaluation of the national betwork of leptospirosis laboratories

INTRODUCCION: La leptospirosis es unaenfermedad febril aguda, frecuentemente subdiagnosticada ysubnotificada por su diversa presentación clínica, baja sospechay falta de disponibilidad de métodos diagnósticos rápidos, simples y eficientes. El Laboratorio Nacional de Referencia de Leptospirosis (LNRL) del Instituto Nacional de EnfermedadesRespiratorias (INER) ôDr. Emilio Coniö produce antígeno termorresistente (TR) y lo distribuye a los laboratorios de la Red Nacional de Laboratorios de Leptospirosis (RNLL). Luego, éstosrealizan la técnica y envían las muestras positivas al LNRL para la confirmación del diagnóstico y las negativas para control de calidad (CC). Sin embargo, hasta la realización de este estudio noexistía un control de uso de TR y envío de muestras. OBJETIVOS: Diseñar y aplicar una herramienta para evaluar operativamente la RNLL. METODOS: Durante 2012 y 2013 se aplicó una planilla de registro de uso de TR, y se crearon y analizaron indicadores de eficiencia de uso, aplicación y reposición del TR y derivación de muestras. RESULTADOS: Se observó que entre 2012 y 2013 mejoró la participación en el CC y la eficiencia de uso del TR.La derivación de muestras positivas y la solicitud de reposición de TR se mantuvieron similares. CONCLUSIONES: La planilladiseñada permitió obtener información de cantidad y calidad de uso del TR, y calcular indicadores para evaluar su distribución y aplicación. Se observó que el desempeño de los laboratoriosmejoró de un año al otro.

INTRODUCTION: Leptospirosis is an acute febrile disease, often underdiagnosed and underreported because of its diverse clinical presentation, low suspicion, and unavailability of rapid, simple and efficient diagnostic methods. TheNational Leptospirosis Reference Laboratory (LNRL) of the National Institute of Respiratory Diseases ôDr. Emilio Coniö produces thermo-resistant antigen (TR) and distributes it to the National Network of Leptospirosis Laboratories (RNLL). These laboratories perform the screening, send the positivesamples for confirmation and the negative ones for quality control. However, until this study there was no control of TR uses and shipment of samples. OBJECTIVES: To design andimplement a tool to operatively assess the RNLL. METHODS: During the years 2012 and 2013, a registration form for the TR use was applied, also creating and analyzing indicators of use efficiency, application and replacement of TR, and referral of samples. RESULTS: It was noted that in the period2012-2013, the participation in the CC and efficiency of use of TR improved. The derivation of positive samples and request for replacement TR remained similar. CONCLUSIONS: The designed form allowed for the first time to obtain information on the quantity and quality of use of the reagent, to design andcalculate indicators to assess the distribution and application of TR during 2012 and 2013. In general, the performance of decentralized laboratories improved from one year to the next.

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations.

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina.

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations.

Comparison of three diagnostic techniques for the detection of leptospires in the kidneys of wild house mice (Mus musculus)

Foram capturados 41 camundongos (Mus musculus) na região urbana, próximo à ferrovia da cidade de Santa Fé, Argentina. Os rins de cada animal capturado foram removidos para estudos bacteriológicos e histológicos. Um dos rins foi imerso em meio semi-sólido de Fletcher para isolamento de leptospiras, as quais foram serologicamente tipificadas. O outro rim foi microscopicamente examinado por coloração de cortes histológicos pela hematoxilina-eosina, impregnação pela prata e imunohistoquímica. Leptospiras pertencentes ao serogrupo Ballum foram isoladas em 16 (39%) das 41 amostras availadas. A presença do agente foi observada em 18 (44%) e 19 (46%) das 41 amostras avaliadas por impregnação pela prata e imunohistoquímica, respectivamente. Leptospiras foram detectadas em grande numero na superfície apical das células epiteliais e no lumen dos túbulos medulares e foram menos frequentemente encontradas na superficie apical de células epiteliais ou no lúmen dos túbulos corticais, o que é considerado achado raro em animais portadores. Lesões microscópicas consistindo de nefrite mononuclear intersticial focal, atrofia glomerular e descamação das células tubulares epiteliais foram observadas em 13 dos 19 animais infectados e em 10 dos 22 animais não infectados. Não houve diferença estatisticamente significativa entre presença de lesões em animais infectados e não infectados (P=0,14). As três técnicas empregadas, isolamento, impregnação pela prata e imunohistoquímica, apresentaram alta concordância (k 0,85) e não apresentaram diferenças estatisticamente significativas (P>0,05). Esse trabalho descreve a presença incomum de leptospira em rins de animais portadores, porém com esse estudo não foi possível estabelecer uma relação entre lesões e presença de leptospira.