An outbreak of strangles associated with a novel genotype of Streptococcus equi subspecies equi in donkeys in China during 2018.
Abstract: Strangles is a highly contagious respiratory disease of equids caused by the bacterium Streptococcus equi subspecies equi. Objective: To identify the cause of an outbreak of strangles that occurred on donkey farms within the Shandong Province of China and determine the prevalence of the disease. Methods: Cross-sectional. Methods: Samples were taken from clinically affected animals to measure the prevalence of strangles within the population of donkeys at six intensive farms in China and identify the SeM type of isolate recovered from affected animals. Diagnosis was confirmed by bacterial isolation, biochemical tests and PCR. Epidemiological data were analysed using Chi-square test and a Fisher's exact two-sided test. The SeM gene of S. equi isolates recovered from affected animals was determined and compared with the SeM database PubMLST-seM. Results: In July and August 2018, an outbreak of strangles occurred on six donkey farms within the Shandong Province of China. The overall prevalence of disease within the different donkey herds was 13.4%. Younger animals were worst affected with 40.3% (83/206) of donkey foals aged under 1 year exhibiting clinical signs compared with 12.5% (191/1525) of donkeys aged one to 2 years and 3.8% (17/442) of donkeys over 2 years of age. Analysis of SeM sequencing data identified that the farms were affected by the same strain of S. equi, SD201807, which contains the novel 136 allele of SeM. Conclusions: Healthy donkeys were not sampled in this study. Conclusions: The number of intensive donkey breeding farms in China has risen recently. The higher numbers of animals that are in closer proximity to one another raise the potential for the transmission of infectious diseases such as strangles. This is the first description of a strangles outbreak among donkey herds in China. The Summary is available in Chinese - see Supporting information.
© 2019 EVJ Ltd.
Publication Date: 2019-04-10 PubMed ID: 30900775DOI: 10.1111/evj.13114Google Scholar: Lookup
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Summary
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This research article discusses an outbreak of strangles, a contagious respiratory disease in animals, in donkey farms in China caused by a novel genotype of the bacterium, Streptococcus equi. The researchers were able to establish an overall disease prevalence of 13.4% among the herds, with younger animals appearing to be most affected.
Research Objective
The researchers undertook this study with the aim of identifying the mean cause of a strangles outbreak in donkey farms within China’s Shandong Province. They sought to secure an understanding of the disease’s prevalence and attempt to determine the specific type (SeM type) of the prominent isolates.
Experimental Methodology
- They decided on a cross-sectional approach, sampling from animals directly affected by the disease. This helped in studying the prevalence within the populations on six intensive donkey farms within China.
- The diagnosis required the bacterial isolation, combination of different biochemical tests, and PCR (Polymerase Chain Reaction), a test to detect genetic material from a specific organism, such as a virus.
- Epidemiological data derived from the study was analyzed with chi-square tests and Fisher’s exact two-tailed tests to compare observed data with expected data.
- An examination was conducted on the specific SeM gene of the S. equi isolates recovered from the affected animals. Comparison was made of this examination with existing records in the ‘PubMLST-seM’ SeM database.
Research Findings
- In July and August 2018, a strangles outbreak on six donkey farms within the Shandong Province of China was recorded.
- Overall, the prevalence of disease among different donkey herds was observed to be 13.4%. It was also observed that younger animals were greatly affected with 40.3% of donkey foals under a year showing signs of the disease. Contrastingly, only 12.5% of donkeys aged between one and two years, and a low 3.8% of donkeys older than two years showed signs.
- Upon analyzing the sequencing data of SeM, it was determined that the same strain of S. equi, SD201807, was affecting the farms. This particular strain contains the novel 136 allele of SeM.
Conclusions Drawn
- The researchers acknowledged that healthy donkeys were not sampled in this particular study.
- They noted a recent increase in the number of intensive donkey breeding farms in China, stressing that this leads to a higher concentration of animals in a single vicinity, which greatly increases the potential for the transmission of infectious diseases.
- This marks the first record of a strangles outbreak specifically among donkey herds in China.
Cite This Article
APA
Dong J, Gao N, Waller AS, Cook FR, Fan S, Yuan D, Du Y, Li F, Norimine J, Zhu W.
(2019).
An outbreak of strangles associated with a novel genotype of Streptococcus equi subspecies equi in donkeys in China during 2018.
Equine Vet J, 51(6), 743-748.
https://doi.org/10.1111/evj.13114 Publication
Researcher Affiliations
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Shandong Donkey Industry Technology Collaborative Innovation Center, College of Agronomy, Liaocheng University, Liaocheng, China.
- Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- The Animal Health Trust, Newmarket, UK.
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
- Department of Veterinary Medical Science, Shandong Vocational Animal Science and Veterinary College, Weifang, China.
- Shandong Donkey Industry Technology Collaborative Innovation Center, College of Agronomy, Liaocheng University, Liaocheng, China.
MeSH Terms
- Animals
- China / epidemiology
- Disease Outbreaks / veterinary
- Equidae
- Genotype
- Phylogeny
- Streptococcal Infections / epidemiology
- Streptococcal Infections / microbiology
- Streptococcal Infections / veterinary
- Streptococcus / genetics
Grant Funding
- SDAIT-27-11 / Shandong Province Modern Agricultural Industry Technology System
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Citations
This article has been cited 12 times.- Rotinsulu DA, Ewers C, Kerner K, Amrozi A, Soejoedono RD, Semmler T, Bauerfeind R. Molecular Features and Antimicrobial Susceptibilities of Streptococcus equi ssp. equi Isolates from Strangles Cases in Indonesia. Vet Sci 2023 Jan 10;10(1).
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