Resumo
A leptospirose bovina é uma doença endêmica nos rebanhos brasileiros, sendo os bovinos considerados hospedeiros de manutenção do sorovar Hardjo e as principais manifestações clínicas nesta espécie estão relacionadas à diminuição do desempenho reprodutivo. Esse sorovar possui dois genótipos: Hardjobovis e Hardjoprajitno. O genótipo Hardjobovis pertence à espécie Leptospira borgpetersenii e o genótipo Hardjoprajitno à espécie Leptospira interrogans. Apesar de ambos causarem problemas reprodutivos nos rebanhos bovinos de todo o mundo, existem diferenças epidemiológicas entre eles. A infecção causada pelo genótipo Hardjobovis é caracterizada pela forma subclínica, ocasionando principalmente aborto; enquanto que o genótipo Hardjoprajitno, caracteriza-se por ser mais patogênica ocasionando problemas reprodutivos e também queda da produção de leite. Apesar de não corresponder com a classificação sorológica, atualmente os melhores métodos de diagnóstico para a leptospirose são aqueles que utilizam ferramentas moleculares. O isolamento bacteriológico, a correta caracterização e identificação genética são extremamente importantes para a compreensão da etiologia, epidemiologia e patogênese das diferentes espécies e genótipos de leptospiras. O objetivo deste trabalho foi isolar e identificar características moleculares através do Multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) e o sequenciamento parcial do gene sec Y de duas cepas isoladas de Leptospira em amostras de urina de bovinos naturalmente infectados de rebanhos leiteiros. Foram selecionadas quinze vacas leiteiras reagentes no teste de soroaglutinação microscópica (SAM) com títulos entre 400 e 800 para o sorovar Hardjo e histórico de falha reprodutiva, tais como aborto e infertilidade. As amostras de urina obtidas de cada animal foram imediatamente semeadas em tubos contendo meio de cultura Ellinghausen-McCullough-Johnson-Harris (EMJH). Das 15 amostras de urina avaliadas, duas leptospiras foram isoladas e nomeadas Londrina 49 e Londrina 54. O perfil MLVA e o sequenciamento parcial do gene sec Y caracterizaram os isolados como L. borgpetersenii sorovar Hardjo genótipo Hardjobovis diferenciando-os da cepa de referência Hardjoprajitno. Este é o primeiro isolamento da L. borgpetersenii sorovar Hardjo genótipo Hardjobovis obtido no Brasil e na América Latina. Portanto, mais estudos são necessários incluindo o isolamento e caracterização molecular de cepas regionais para obter um melhor conhecimento sobre a epidemiologia do sorovar Hardjo em bovinos o que podem ajudar em futuras estratégias de prevenção e controle da leptospirose bovina.
Bovine leptospirosis is an endemic disease in bovine Brazilian herds, and the cattle are considered the serovar Hardjo maintenance hosts and the clinical manifestations in this species are related to decreased reproductive performance. This serovar has two genotypes: Hardjobovis and Hardjoprajitno. The genotype Hardjobovis belongs to the specie Leptospira borgpetersenii and Hardjoprajitno genotype to the specie Leptospira interrogans. Although both cause reproductive failure in cattle herds around the world, there are epidemiological differences between them. The infection caused by Hardjobovis genotype is characterized by subclinical form, especially causing abortion; while Hardjoprajitno genotype, is more pathogenic causing reproductive problems and also decreased milk production. Although not correspond with the serological classification, currently the best diagnostic methods for leptospirosis are those using molecular tools. The bacterial isolation, the correct characterization and genetic identification are important for understanding the etiology, epidemiology and pathogenesis of the different specie and genotype of Leptospira. The objective of this study was to isolate and identify molecular characteristics through Multilocus variable-number tandem repeat (VNTR) analysis (MLVA) and sequencing of the sec Y partial gene of two isolated strains of Leptospira in urine samples from bovine naturally infected of dairy herds. Fifteen dairy cows reagents in the microscopic agglutination test (MAT) with titles between 100 and 800 for the serovar Hardjo and history of reproductive failure were selected, such as abortion and infertility. The urine samples obtained from each animal were immediately seeded in tubes containing culture medium Ellinghausen-McCullough-Johnson-Harris (EMJH). The identification of the isolates was performed by Multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) technique and phylogenetic analysis of partial sequence of gene sec Y. From the 15 urine samples evaluated, two leptospiras were isolated and named Londrina 49 and Londrina 54 strains. The MLVA profile and partial sequencing of gene sec Y characterized the isolates as L. borgpetersenii serovar Hardjo genotype Hardjobovis differing them from Hardjoprajitno reference strain. Therefore, more studies are needed including isolation and molecular characterization from regional strains to obtain a better knowledge about epidemiology of serovar Hardjo in bovine which may assist in future strategies of prevention and control of bovine leptospirosis
Resumo
The main goal of this study was to evaluate the prevalence of leptospirosis among field rodents of Tiruchirappalli district, Tamil Nadu, India. In total 35 field rats were trapped and tested for seroprevalence by the microscopic agglutination test (MAT). Isolation of leptospires was performed from blood and kidney tissues and characterized to serovar level. Genomospecies identification was carried out using 16S rRNA and lipL32 gene sequencing. The molecular phylogeny was constructed to find out species segregation. Seroprevalence was about 51.4 %, and the predominant serovars were Autumnalis, Javanica, Icterohaemorrhagiae and Pomona. Two isolates from the kidneys were identified as serovar Javanica of Serogroup Javanica, and sequence based molecular phylogeny indicated these two isolates were Leptospira borgpetersenii.