Nucleotide sequence heterogeneity in the small subunit ribosomal RNA gene within Theileria equi from horses in Sudan.
Abstract: This is a molecular epidemiological investigation on Theileria equi, a causative agent of equine piroplasmosis. Blood samples were collected from 127 horses from different geographical locations in Sudan. The small subunit of rRNA gene (18S; ~1,600 bp) was amplified from 20 positive field samples and subsequently subjected to direct sequencing and analysis to reveal possible strain differences and the presence of a novel species or genotypes. Sequences were compared with published sequences mainly from South African and Spanish isolates. Eleven distinct T. equi sequences within 18S rRNA gene were identified to have occurred, and three genotypes were lying within the three previously identified groups. Alignments demonstrated extensive sequence variation in the hypervariable region of the 18S rRNA gene and many SNPs within the Sudanese T. equi isolates.
Publication Date: 2009-12-02 PubMed ID: 19953269DOI: 10.1007/s00436-009-1691-7Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study is about the identification of different strains of Theileria equi, a protozoan parasite causing equine piroplasmosis, in horses from various regions of Sudan. The examination involved evaluation of the genetic variation in the small subunit of the parasite’s ribosomal RNA gene.
Methodology
- Blood samples were taken from 127 horses from different geographical locations in Sudan, to account for variations in strains across geography.
- A subsection of the ribosomal RNA gene of the causative protozoan, known as the small subunit or 18S, was selected for analysis. This choice is due to its substantial length (~1,600 base pairs) and its well-established use in similar genetic studies.
- Of these, 20 Theileria equi positive samples were selected and subjected to a process called “amplification”. This technique, often used in genetic studies, multiplies a specific section of DNA to make it easier to analyse.
- These amplified samples were then directly sequenced – finding the exact order of nucleotides in the gene.
Analysis
- Gene sequences obtained from Sudanese horses were compared to previously published sequences, primarily from South Africa and Spain. This comparative method reveals differences and similarities in the genetic structure, pointing to potential strain variations or novel species.
- The team managed to identify eleven distinct T. equi sequences within the 18S rRNA gene, implying the presence of multiple strains within the sampled population.
- Additionally, three genotypes were fitting within previously recognised groups, suggesting they aren’t novel but variations of existing strains.
- The researchers also assessed “hypervariable” regions of the gene. These sections are known for high mutation rates, often causing significant differences between strains. An extensive variation in these sections strengthens the argument for multiple strains within the same species.
- In conclusion, numerous single nucleotide polymorphisms (SNPs – genetic variations at a single position in a DNA sequence) were noted in the Sudanese T. equi isolates, contributing to the strain diversity in these parasites.
This study helps in understanding the genetic diversity of T. equi within various horse populations. Identifying these different strains is crucial for public health planning and disease control strategies, as they can determine the efficacy of available treatments and potential resistance development.
Cite This Article
APA
Salim B, Bakheit MA, Kamau J, Nakamura I, Sugimoto C.
(2009).
Nucleotide sequence heterogeneity in the small subunit ribosomal RNA gene within Theileria equi from horses in Sudan.
Parasitol Res, 106(2), 493-498.
https://doi.org/10.1007/s00436-009-1691-7 Publication
Researcher Affiliations
- Department of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan. bashirsalim@gmail.com
MeSH Terms
- Animals
- Cluster Analysis
- DNA, Protozoan / chemistry
- DNA, Protozoan / genetics
- DNA, Ribosomal / chemistry
- DNA, Ribosomal / genetics
- Genotype
- Horse Diseases / parasitology
- Horses / parasitology
- Molecular Epidemiology
- Molecular Sequence Data
- Phylogeny
- Polymorphism, Genetic
- RNA, Ribosomal, 18S / genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Sudan / epidemiology
- Theileria / classification
- Theileria / genetics
- Theileria / isolation & purification
- Theileriasis / epidemiology
- Theileriasis / parasitology
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