Detection of reactive canines to Leptospira in Campeche City, Mexico / Detection of reactive canines to Leptospira in Campeche City, Mexico.

Leptospira reactivity in stray and household dogs in Campeche as well as associated risk factors to the seropositivity in household dogs have been herein determined. The survey included 323 dogs, 142 of which were stray dogs and 181 household dogs. Nine Leptospira interrogans serovars were tested by the microagglutination test. Reactivity was 21.3

corresponded to household dogs and 26.7

), and Leptospira Icterohaemorrhagiae (16.12

) were the most common serovars reacting against the serum of household animals, while Leptospira Canicola (15.78

), and Leptospira Pomona (7.89

) were those reacting in stray dogs. Results showed that all dogs have been in contact with different Leptospira serovars and outdoor exposure is the main infection risk factor.

Survey of Leptospira spp in pampas deer (Ozotoceros bezoarticus) in the Pantanal wetlands of the state of Mato Grosso do Sul, Brazil by serology and polymerase chain reaction

This work reports a survey of Leptospira spp in pampas deer (Ozotoceros bezoarticus) in the Pantanal wetlands of the state of Mato Grosso do Sul, Brazil by serology and polymerase chain reaction (PCR). Seventy pampas deer were captured in the dry season and surveyed using PCR, microscopic agglutination test (MAT) (n = 51) and by both techniques (n = 47). PCR detected infections in two pampas deer and MAT detected infections in three. Through sequencing and phylogenetic analyses, the PCR-amplified fragment detected in deer was identified as Leptospira interrogans. Serovars Pomona and Butembo were detected using MAT and the highest titre was 200 for serovar Pomona. Epidemiological aspects of the findings are discussed.

Differential response of cytokines induced by Leptospira interrogans, serogroup Pomona, serovar Pomona, in mouse and human cell lines.

Leptospira interrogans, the causative agent of leptospirosis, is an important zoonotic bacterium. The mechanisms and roles of cytokine induction in both humans and animals remain unclear. Therefore, the IFN-gamma, IL-6, IL-10 and IL-12 levels were measured by enzyme-linked immunosorbent assay (ELISA) in human THP-1 and mouse RAW 264.7 monocyte cell lines following stimulation with heat-killed Leptospira interrogans serogroup Pomona serovar Pomona, L. biflexa, E. coli or Salmonella group B. The production of IL-6 and IL-12 were higher and rose more rapidly in the RAW 264.7 cells with all bacteria. The IL-10 was not detected in the RAW 264.7 cells when induced by leptospires. The IFN-gamma level in human peripheral blood mononuclear cells (PBMCs) induced by leptospires was also significantly lower than with other bacteria. When IL-10 and IL-12 mRNA expressions were detected in hamster's spleen, their patterns were similar to what was observed in THP-1 in that IL-12 was only slightly increased while IL-10 expression was high. Moreover, the IFN-gamma expression could not be detected in hamsters. The more potent cytokine responses in the RAW 264.7 cells may indirectly reflect the disease outcome in mice which render them to be a good reservoir of leptospirosis. Whether these cytokines have contributed to immunoprotection during the L. interrogans infection remains to be further investigated.

Identificação da Leptospira interrogans sorovar pomona em camundongos geneticamente selecionados, para a alta e baixa produção de anticorpos, através da técnica de imunoperoxidase em tecido renal e isolamento bacteriano em meio de Fletcher / Identification of Leptospira interrogans serovar pomona in mice genetically selected for high and low antibody production, by means of the immunoperoxidase technique in renal tissue and bacterial isolation in Fletcher medium

O presente trabalho teve por objetivo identificar a presença da Leptospira interrogans sorovar pomona em camundongos geneticamente selecionados para a alta e baixa resposta a anticorpos. Todos os animais foram submetidos ao isolamento bacteriano, imunohistoquímica (imunoperoxidase) em cortes de tecido renal e coloração através da hematoxilina-eosina. A técnica de imunoperoxidase apresentou-se pouco mais sensível em relação ao cultivo, entretanto, ambas foram bons parâmetros de identificação do agente. Presença de lesões renais mais intensas ocorreram em períodos em que houve maior número de bactérias isoladas em meio de cultivo. Camundongos da linhagem HIV-A conseguiram eliminar as leptospiras com maior eficiência e rapidez em relação as linhagem LIV-A, entretanto o estudo demonstrou que ambas linhagens da seleção IV-A foram eficientes em controlar o processo infeccioso.

The present work had the objective of identifying the presence of Leptospira interrogans serovar pomona in mice that had been genetically selected for high and low response to antibodies. All the animals were subjected to bacterial isolation, immunohistochemical analysis (immunoperoxidase) in renal tissue sections and hematoxylin-eosin staining. The immunoperoxidase technique was little more sensitive than culturing, but both were good parameters for agent identification. More severe renal lesions were present at times when there were greater numbers of bacteria isolated in culture medium. Mice of the lineage HIV-A were able to eliminate the Leptospira more efficiently and faster than the lineage LIV-A could. However, the study demonstrated that both lineages of the IV-A selection were efficient in controlling the infectious process.

Inmunogenicidad y capacidad protectora en hamsters de vacunas antileptospirósicas monovalentes de células enteras del serogrupo Ballum / Immunogenicity and protective capacity of leptospiral whole-cell monovalent serogroup Ballum vaccines in hamsters

El serogrupo Ballum de Leptospira constituye en la actualidad la primera causa de leptospirosis humana en Cuba. Vacunas de células enteras químicamente inactivadas fueron formuladas a partir de dos cepas clínicas de Leptospira interrogans serogrupo Ballum empleando como adyuvante hidróxido de aluminio. Los niveles de aglutininas inducidos en hamsters por una u otra preparación vacunal fueron estimados mediante aglutinación microscópica y la actividad IgG específica fue cuantificada mediante ELISA. La capacidad de protección homóloga y heteróloga contra la infección letal y subletal se determinó mediante el desafío con 100 y 10 000 DL50 de cinco cepas virulentas pertenecientes a los serogrupos Ballum, Canicola, Icterohaemorrhagiae y Pomona. Las evaluaciones realizadas demostraron que ambas vacunas fueron inmunogénicas e indujeron una completa protección homóloga en el modelo animal empleado. La protección cruzada frente a serogrupos heterólogos solo fue significativa en una de las preparaciones monovalentes frente al desafío con 100 DL50 de Canicola. Como resultado de este estudio se pudo comprobar la alta inmunogenicidad y capacidad protectora en hamsters de vacunas monovalentes de células enteras formuladas a partir de dos cepas candidatas vacunales del serogrupo de Leptospira de mayor circulación en humanos en Cuba no incluido en la vacuna actualmente disponible.

Leptospira serogroup Ballum is at present the first cause of human leptospirosis in Cuba. Killed whole-cell vaccines were formulated with two clinical isolates of Leptospira interrogans serogroup Ballum using aluminum hydroxide as adjuvant. Agglutinins levels induced by each vaccine in hamsters were estimated by microscopic agglutination test and specific IgG activities were quantified by a whole cell-based enzyme-linked immunosorbent assay. Homologous and cross protective capacity against lethal and sublethal infection were determined in vaccinated animals by challenge with 100 and 10 000 LD50 of five virulent strains belonging to serogroups Ballum, Canicola, Icterohaemorrhagiae and Pomona. Both monovalent serogroup Ballum vaccines were immunogenic and induced complete homologous protection in the animal model. Cross-protection was only significant in one of the two vaccines against challenge with 100 LD50 of serogroup Canicola. The results of this study demonstrate the high immunogenicity and protective capacity in hamsters of whole-cell monovalent vaccines formulated with two vaccine candidate strains belonging to the most prevalent serogroup of Leptospira in Cuba.