Novel MLST sequence types of pathogenic Leptospira spp.: Opening the black box of animal leptospirosis in Brazil.

In the current context of the emergence of certain infectious diseases and discussion of the One Health concept for many of these, the study of leptospirosis - both in domestic and wild hosts - cannot be neglected. The study of animal leptospirosis has evolved in recent years. It has been demonstrated that the human-animal-environment interface is more important than previously thought. In the present study, 35 strains of five pathogenic Leptospira species were isolated from different animal species in Brazil and characterized by rrs, secY, and Multilocus Sequence Typing (MLST) sequencing. Phylogenetic inferences were performed and the molecular diversity of the populations (intra- and inter-population levels) was evaluated. Among the five studied species, 18 different sequence types (STs) were found (22 new alleles and 11 new STs). eBURST analysis revealed two clonal complexes (CCs) and seven singletons. A high genetic diversity was demonstrated (H = 0.954 ± 0.017), mainly for the L. santarosai population (H = 0.942 ± 0.034, n = 20). The same strain was identified in different host species, as well as strains with zoonotic potential circulating in the country. Although the difficulty of culturing Leptospira strains is well known, the high variability of the strains found in Brazil highlights the importance of animals in maintaining the biological cycle of the bacterium in nature. Moreover, the selection of autochthonous strains for the development of vaccines becomes a challenge.

Detection of East/Central/South African genotype Chikungunya virus during an outbreak in a southeastern state of Brazil.

Chikungunya virus (CHIKV) is an arbovirus transmitted by Aedes mosquitoes that was first identified in Brazil in 2014. It causes a febrile illness characterised by severe arthralgia and rash. Our group investigated a suspected CHIKV outbreak in Governador Valadares, state of Minas Gerais, Brazil and from 25 acute-phase patients, 10 had qRT-PCR positive sera samples and had E1 partial sequence amplified and Sanger sequenced. Samples were identified as East/Central/South African (ECSA) genotype by phylogenetic analysis and clustered with CHIKV sequences isolated in the neighbour state of Bahia. Our findings confirm previous predictions that ECSA genotype would spread through northeast and southeast of Brazil.

Genotyping of Leptospira directly in urine samples of cattle demonstrates a diversity of species and strains in Brazil.

The aim of this study was to identify Leptospira in urine samples of cattle by direct sequencing of the secY gene. The validity of this approach was assessed using ten Leptospira strains obtained from cattle in Brazil and 77 DNA samples previously extracted from cattle urine, that were positive by PCR for the genus-specific lipL32 gene of Leptospira. Direct sequencing identified 24 (31·1%) interpretable secY sequences and these were identical to those obtained from direct DNA sequencing of the urine samples from which they were recovered. Phylogenetic analyses identified four species: L. interrogans, L. borgpetersenii, L. noguchii, and L. santarosai with the most prevalent genotypes being associated with L. borgpetersenii. While direct sequencing cannot, as yet, replace culturing of leptospires, it is a valid additional tool for epidemiological studies. An unexpected finding from this study was the genetic diversity of Leptospira infecting Brazilian cattle.