Detection of Neorickettsia risticii, the agent of Potomac horse fever, in horses from Rio de Janeiro, Brazil.
Abstract: This study aims to report the presence of Neorickettsia risticii DNA in blood samples from naturally infected horses in Rio de Janeiro, provide clinicopathological findings related to the infection, and report the phylogenetic diversity of the 16S rDNA of N. risticii in order to evaluate its heterogeneity. Real-time quantitative polymerase chain reaction (qPCR) was performed to investigate the presence of N. risticii in samples collected from horses (n = 187). Five positive samples were found in the molecular screening. Hypoalbuminemia and high levels of creatine kinase and lactate dehydrogenase were the predominant findings in the biochemical analysis. The sequences were similar to those of N. risticii. Phylogenetic analysis revealed genotype segregation based on the geographical distribution in the N. risticii sequence clade. Dendrograms constructed with five hypervariable regions revealed that V4 distinguished Neorickettsia at the species level and produced a phylogeny that best represented the phylogeny obtained with the complete 16S rDNA sequence. This is the first report of N. risticii DNA in the blood of Brazilian horses based on sequences deposited in GenBank. Further studies are necessary to clarify the epidemiological chain of this vector-borne parasite in order to determine and establish appropriate preventive measures in the equine trading market.
Publication Date: 2020-04-29 PubMed ID: 32350359PubMed Central: PMC7190851DOI: 10.1038/s41598-020-64328-2Google Scholar: Lookup
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Summary
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The research article outlines the detection of a harmful pathogen, Neorickettsia risticii, in horses in Rio De Janeiro, Brazil. The study aimed to not only identify the presence of the bacteria but also understand its genetic diversity and associated clinical symptoms in infected horses.
Methodology and Objectives
- The goal of the study was to identify the presence of Neorickettsia risticii DNA in blood samples from horses in Rio de Janeiro. It also aimed to provide information on the clinical signs of the infection in horses.
- Additionally, the examination of the phylogenetic diversity of the 16S rDNA of Neorickettsia risticii was conducted to assess its heterogeneity. The 16S rDNA is a type of DNA sequence that scientists often use to classify and identify bacteria.
- The team employed real-time quantitative polymerase chain reaction (qPCR), a technique used to amplify and detect DNA sequences, on samples collected from 187 horses.
Findings
- Five samples tested positive for N. risticii in the molecular screening. Among these horses, low levels of albumin, and high levels of creatine kinase and lactate dehydrogenase were found, suggesting these could be key indicators of the infection.
- The sequences identified were similar to those of N. risticii, confirming the presence of this bacteria. Phylogenetic analysis, a method used to study the evolutionary relationships between organisms, revealed a pattern of genotype segregation based on geographical distribution within the sequence clade of N. risticii. A clade is a group of organisms believed to have a common ancestor.
- Dendrograms were constructed using five hypervariable regions and it was observed that the V4 region was effective in identifying Neorickettsia at the species level, and it displayed a phylogeny that was representative of the one acquired with the full 16S rDNA sequence.
Implications and Recommendations
- It’s the first time that N. risticii DNA has been reported in the blood of Brazilian horses, a finding that could have significant implications for veterinary care and the horse trading market in the region.
- The researchers recommended further investigation into the epidemiological chain of this vector-borne parasite. An understanding of how the bacteria spreads and its impact is crucial for establishing effective preventive measures in the equine trading market.
Cite This Article
APA
Paulino PG, Almosny N, Oliveira R, Viscardi V, Müller A, Guimarães A, Baldani C, da Silva C, Peckle M, Massard C, Santos H.
(2020).
Detection of Neorickettsia risticii, the agent of Potomac horse fever, in horses from Rio de Janeiro, Brazil.
Sci Rep, 10(1), 7208.
https://doi.org/10.1038/s41598-020-64328-2 Publication
Researcher Affiliations
- Department of Epidemiology and Public Health, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil. patgpaulino@gmail.com.
- Department of Veterinary Clinic and Pathology, Federal Fluminense University, Niteroi, Brazil.
- Department of Veterinary Clinic and Pathology, Federal Fluminense University, Niteroi, Brazil.
- Department of Veterinary Clinic and Pathology, Federal Fluminense University, Niteroi, Brazil.
- Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis.
- Instituto de Ciencias Clínicas Veterinarias, Universidad Austral de Chile, Valdivia, Chile.
- Department of Veterinary Medicine and Surgery, Veterinary Institute, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
- Department of Veterinary Medicine and Surgery, Veterinary Institute, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
- Department of Animal Parasitology, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
- Department of Animal Parasitology, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
- Department of Animal Parasitology, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
- Department of Epidemiology and Public Health, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropedica, RJ, 23890000, Brazil.
MeSH Terms
- Anaplasmataceae Infections / diagnosis
- Anaplasmataceae Infections / genetics
- Anaplasmataceae Infections / microbiology
- Anaplasmataceae Infections / veterinary
- Animals
- Brazil
- DNA, Bacterial / genetics
- DNA, Ribosomal / genetics
- Horse Diseases / diagnosis
- Horse Diseases / genetics
- Horse Diseases / microbiology
- Horses
- Neorickettsia risticii / genetics
- Neorickettsia risticii / isolation & purification
- Phylogeny
- RNA, Bacterial / genetics
- RNA, Ribosomal, 16S / genetics
Conflict of Interest Statement
The authors declare no competing interests.
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Citations
This article has been cited 5 times.- Perles L, Barreto WTG, Macedo GC, Herrera HM, Machado RZ, André MR. Neorickettsia sp. in coatis (Nasua nasua) in Brazil. Rev Bras Parasitol Vet 2023;32(3):e006623.
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