Longitudinal Dichelobacter nodosus status in 9 sheep flocks free from clinical footrot

Locher, Iwan; Greber, Deborah; Holdener, Kerstin; Lüchinger, Rita; Haerdi-Landerer, Christina; Schüpbach, Gertraud; Frey, Joachim; Steiner, Adrian (2015). Longitudinal Dichelobacter nodosus status in 9 sheep flocks free from clinical footrot. Small ruminant research, 132, pp. 128-132. Elsevier 10.1016/j.smallrumres.2015.10.021

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Footrot is a widespread problem in Swiss sheep farming. The objectives of this study were to determine whether flocks which were clinically free from footrot carry virulent strains of Dichelobacter nodosus, and to describe the infection dynamics for flocks and individual sheep. To this purpose, a new PCR-diagnostic tool was used, which is able to distinguish benign from virulent D. nodosus. Nine farms were examined three times at intervals of 6 months. Cotton swabs were used to collect samples from the interdigital skin to analyze for the presence of virulent and benign strains of D. nodosus. Additionally, epidemiological data of the farms were collected with the aid of a standardized questionnaire. On four farms, benign strains were diagnosed at each visit; in one farm, benign strains were detected once only. Two flocks revealed sheep infected with virulent D. nodosus throughout the study but without clinical evidence of footrot. In two flocks, the virulent strains of D. nodosus were introduced into the flock during the study period. In one farm, clinical symptoms of virulent footrot were evident only two weeks after the positive finding by PCR. Only individual sheep with previously negative status, but none with previously benign status became infected with virulent strains during the study. The newly developed competitive RT PCR proved to be more sensitive than clinical diagnosis for detecting footrot infection in herds, as it unequivocally classified the four flocks as infected with virulent D. nodosus, even though they did not show clinical signs at the times of sampling. This early detection may be crucial to the success of any control program. Both new infections with virulent strains could be explained by contact with sheep from herds with virulent D. nodosus as evaluated from the questionnaires. These results show that the within-herd eradication of footrot becomes possible using the competitive PCR assay to specifically diagnose virulent D. nodosus.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Research Foci > Veterinary Public Health / Herd Health Management
05 Veterinary Medicine > Research Foci > Host-Pathogen Interaction
05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV)
05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > Clinic for Ruminants
05 Veterinary Medicine > Department of Clinical Research and Veterinary Public Health (DCR-VPH) > Veterinary Public Health Institute
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP)
05 Veterinary Medicine > Department of Clinical Research and Veterinary Public Health (DCR-VPH)
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Veterinary Bacteriology

UniBE Contributor:

Locher, Iwan; Greber, Deborah; Schüpbach, Gertraud; Frey, Joachim and Steiner, Adrian

Subjects:

600 Technology > 610 Medicine & health
600 Technology > 630 Agriculture

ISSN:

0921-4488

Publisher:

Elsevier

Language:

English

Submitter:

Patrik Zanolari

Date Deposited:

01 Mar 2016 17:04

Last Modified:

17 Aug 2018 08:06

Publisher DOI:

10.1016/j.smallrumres.2015.10.021

BORIS DOI:

10.7892/boris.76204

URI:

https://boris.unibe.ch/id/eprint/76204

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