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Novel Streptococcus equi strains causing strangles outbreaks in Arabian horses in Egypt
Author(s) -
Tartor Yasmine H.,
ELNaenaeey ElSayed Y.,
Gharieb Nesreen M.,
Ali Wessam S.,
Ammar Ahmed M.
Publication year - 2020
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.13584
Subject(s) - streptococcus equi , biology , multiplex polymerase chain reaction , typing , polymerase chain reaction , outbreak , genotype , microbiology and biotechnology , allele , virology , horse , gene , genetics , bacteria , paleontology
Strangles displays a major challenge to veterinary medicine worldwide. However, no data on Streptococcus equi subsp. equi ( S. equi ) M protein alleles have been reported so far from Arabian horses. We report here for the first time the S. equi SeM alleles causing strangles in Arabian horses, and the associated risk factors for the disease. Duplicate samples from one hundred Arabian horses with acute strangles in confirmed outbreaks and sporadic cases were analysed by phenotypic methods and multiplex polymerase chain reaction (PCR) targeting streptokinase precursor, see I and sod A genes. PCR and sequencing of S. equi SeM gene were employed for strains typing, and the four superantigens were determined among the allelic variants. Direct‐sample PCR confirmed and highly positively correlated ( r = .85) with the phenotypic results, and detected S. equi in five samples more than the conventional culture. A combination of multiplex PCR from samples and culture could successfully identify S. equi (92%), S. zooepidemicus (5%) and S. equisimilis (3%). SeM typing demonstrated five SeM alleles, including four previously unidentified alleles that were deposited in the PubMLST‐SeM database. SeM‐139 and SeM‐141 are related to some strains that were recently recovered from donkeys in China. SeM‐140 and SeM‐199 are related to a group of alleles from horses in Europe. Variation in the presence of see M , see H and see L superantigens was found across the four novel alleles without interference with the severity of strangles and clinical presentation seen in different outbreaks. Horse age was the most important factor in developing strangles, followed by seasonality and the diagnosis of strangles in the previous year. These new findings comprise a significant contribution to the horse industry through the identification of novel S. equi SeM types that may bolster measures for strangles control as the identified SeM alleles will certainly help in the development of SeM‐containing vaccine.