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Outbreaks of diarrhoea ('winter scours') in weaned Merino sheep in south-eastern Australia.
- Source :
-
Australian veterinary journal [Aust Vet J] 2018 May; Vol. 96 (5), pp. 176-183. - Publication Year :
- 2018
-
Abstract
- Objective: Identify the cause of outbreaks of diarrhoea during winter that are not attributable to gastrointestinal nematodes in weaned Merino sheep in the high rainfall regions of south-eastern Australia and determine the efficacy of antimicrobials used to treat this syndrome.<br />Methods: We investigated 45 outbreaks on 24 farms. Faecal samples from affected animals were cultured for Yersinia, Campylobacter and Salmonella spp. Risk factors, including rainfall, temperature and worm egg count (WEC), were assessed. Yersinia spp. were identified with molecular tests and susceptibility to four antimicrobials was determined.<br />Results: Yersinia pseudotuberculosis serotype III and virulent Y. enterocolitica were most frequently isolated. The frequency and severity of disease varied between region, farm and year. Yersinia pseudotuberculosis was detected only during winter, but Y. enterocolitica was present in all seasons. Pathogenic Yersinia species were more often isolated when WECs exceeded 500 eggs/g. A high proportion of Y. enterocolitica and Y. pseudotuberculosis were resistant to sulfafurazole (64% and 86.9%, respectively).<br />Conclusions: A bacterial enteritis caused by pathogenic Yersinia was the cause of the winter scours syndrome in the 24 flocks investigated. The use of molecular testing increased the sensitivity of detection and identification of Yersinia spp. No clear association between weather, WEC and disease was established, suggesting complex interactions between risk factors are more important than any single factor. Sulfonamides should not be routinely used to treat this syndrome. Rather, during an outbreak the targeted use of an effective antimicrobial, such as oxytetracycline, should be integrated with grazing management strategies, including moving affected mobs onto lower risk pastures and decreasing the stocking rate.<br /> (© 2018 Australian Veterinary Association.)
- Subjects :
- Animal Husbandry
Animals
Anti-Bacterial Agents therapeutic use
Autopsy veterinary
Campylobacter isolation & purification
Cross-Sectional Studies
Diarrhea drug therapy
Diarrhea epidemiology
Diarrhea microbiology
Disease Outbreaks veterinary
Feces microbiology
Gram-Negative Bacterial Infections drug therapy
Gram-Negative Bacterial Infections epidemiology
Oxytetracycline therapeutic use
Salmonella isolation & purification
Seasons
Serotyping veterinary
Sheep
Sheep Diseases drug therapy
South Australia epidemiology
Sulfonamides therapeutic use
Treatment Outcome
Yersinia isolation & purification
Diarrhea veterinary
Gram-Negative Bacterial Infections veterinary
Sheep Diseases epidemiology
Sheep Diseases microbiology
Subjects
Details
- Language :
- English
- ISSN :
- 1751-0813
- Volume :
- 96
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Australian veterinary journal
- Publication Type :
- Academic Journal
- Accession number :
- 29691860
- Full Text :
- https://doi.org/10.1111/avj.12696