Characterisation of South African field Ehrlichia ruminantium using multilocus sequence typing

Onderstepoort Journal of Veterinary Research

Field Value
Title Characterisation of South African field Ehrlichia ruminantium using multilocus sequence typing
Creator Dlamkile, Zinathi Neves, Luis Morar-Leather, Darshana Brandt, Christopher Pretorius, Alri Steyn, Helena Liebenberg, Junita
Subject — Ehrlichia ruminantium; heartwater; characterisation; pCS20; multilocus sequence typing; MLST; phylogenetic; PCR
Description Heartwater, one of the major tick-borne diseases of some domestic and wild ruminants in Africa, is caused by Ehrlichia ruminantium. The genetic diversity of E. ruminantium isolates renders the available vaccine ineffective against certain virulent isolates. To better understand the E. ruminantium genotypes in South Africa, a total of 1004 Amblyomma hebraeum tick deoxyribonucleic acid (DNA) samples from cattle in three South African provinces were tested by pCS20 Sol1 real-time polymerase chain reaction (qPCR) and characterised by multilocus sequence typing (MLST) using five housekeeping genes. Out of 1004 samples tested, 222 (22%) were positive for E. ruminantium. The occurrence of E. ruminantium in Mpumalanga, KwaZulu-Natal and Limpopo provinces was 19%, 22% and 27%, respectively. The E. ruminantium positive samples were screened for housekeeping genes and sequenced. Phylogenetic analysis revealed three main lineages: clade 1 made up of worldwide isolates (eastern, southern Africa, and Caribbean isolates), clade 2 comprised only West African isolates and clade 3 consisted of Omatjenne, Kümm2 and Riverside. Some study sample sequences were not identical to any of the reference isolates. However, they could all be grouped into the worldwide clade. Genetic variation in the sequenced regions was observed in the form of single nucleotide polymorphisms (SNPs). Using MLST to characterise E. ruminantium field isolates allowed the South African genotypes to be clearly distinguished from the distinct West African isolates.Contribution: Characterisation of E. ruminantium field isolates is important for the control of heartwater and contributes to preliminary knowledge required for the development of a more practical vaccine against heartwater.
Publisher AOSIS
Contributor Long term EU‐ Africa research and innovation Partnership on food and nutrition security and sustainable Agriculture Agricultural Sector Education Training Authority Belgian Directorate-General for Development Co-operation Framework Agreement 4
Date 2023-11-14
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — —
Format text/html application/epub+zip text/xml application/pdf
Identifier 10.4102/ojvr.v90i1.2119
Source Onderstepoort Journal of Veterinary Research; Vol 90, No 1 (2023); 8 pages 2219-0635 0030-2465
Language eng
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Rights Copyright (c) 2023 Zinathi Dlamkile, Luis Neves, Darshana Morar-Leather, Christopher Brandt, Alri Pretorius, Helena Steyn, Junita Liebenberg