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Does whole flock gamithromycin treatment reduce the prevalence of footrot in sheep?

Clinical Scenario

Mr Jones runs a flock of 700 Welsh mountain ewes and has been struggling with high levels of lameness in his ewes for many years. He has heard of another vet practice advocating injecting all the sheep in a flock with a macrolide antibiotic to eradicate footrot from a flock once and for all. He asks if he should do it on his farm.  You wonder if administering whole flock treatment with gamithromycin would reduce the prevalence of footrot.....

3-Part Question (PICO)

In [sheep with footrot] does [whole flock gamithromycin treatment] reduce [the prevalence of disease]?

Search Strategy and Summary of Evidence

Search Strategy

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) 1946 to Present using the OVID interface

(sheep.mp. OR ovine.mp. OR ovines.mp. OR ovis.mp. OR exp sheep/)

AND

(footrot.mp. OR foot rot.mp. OR scald.mp. OR strip.mp. OR fusobacterium necrophorum.mp. OR dichelobacter nodosus.mp. OR infectious pododermatitis.mp. OR interdigital dermatitis.mp. OR fusobacterium.mp. OR dichelobacter.mp. OR pododermatitis.mp. OR F necrophorum.mp. OR D nodosus.mp. OR exp Foot Rot/ OR exp Fusobacterium necrophorum/ OR exp Dichelobacter nodosus/ OR exp Fusobacterium Infections/ OR exp Fusobacterium/ OR exp Foot Dermatoses/)

AND

(gamithromycin.mp. OR Zactran.mp. OR macrolide.mp. OR macrolides.mp. OR exp Macrolides/)

CAB Abstracts 1910 to Present using the OVID interface

(sheep.mp. OR ovine.mp. OR ovines.mp. OR ovis.mp. OR exp sheep/)

AND

(footrot.mp. OR foot rot.mp. OR scald.mp. OR strip.mp. OR fusobacterium necrophorum.mp. OR dichelobacter nodosus.mp. OR infectious pododermatitis.mp. OR interdigital dermatitis.mp. OR fusobacterium.mp. OR dichelobacter.mp. OR pododermatitis.mp. OR F necrophorum.mp. OR D nodosus.mp. OR exp foot rot/ OR exp Dichelobacter/ OR exp Dichelobacter nodosus/ OR exp fusobacterium necrophorum/ OR exp Fusobacterium/ OR exp interdigital dermatitis/ OR exp Pododermatitis/)

AND

(gamithromycin.mp. OR Zactran.mp. OR macrolide.mp. OR macrolides.mp. OR exp macrolide antibiotics/)

Search Outcome

MEDLINE

  • 11 papers found in MEDLINE search
  • 9 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 1 papers excluded as they are review articles/in vitro research/conference proceedings
  • 1 total relevant papers from MEDLINE

CAB Abstracts

  • 28 papers found in CAB search
  • 24 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 3 papers excluded as they are review articles/in vitro research/conference proceedings
  • 1 total relevant papers from CAB

Total relevant papers

1 relevant papers from both MEDLINE and CAB Abstracts

Summary of Evidence

Forbes et al. (2014) Germany and Denmark

Title:

Field studies on the elimination of footrot in sheep through whole flock treatments with gamithromycin.

Patient group:

One flock of German Merinolandschaf sheep and 48 Danish sheep flocks

Study Type:

Case series

Outcomes:
  • Foot lesions scored from 0 to 5 (0 being normal) (in all 184 animals in Merionlandschaf flock)
  • PCR analysis for presence of D nodosus from interdigital samples (from a proportion of animals in Merinolandschaf flock, and in a sample of 8 animals from each Danish flock)
  • Lameness (only reported in Merinolandschaf flock)
Key Results:
  • Merinolandschaf flock:
  • At the beginning of the study, 117/184 animals had footrot lesion score of >=1; at day 23, 8 animals had footrot lesion score >1 which were re-treated; and at day 45, no positive scores were seen.
  • No initial lameness scoring is reported, but at day 23, 8 animals were lame and were re-treated, at day 45, no lameness was seen. During the following 6 months, 5 animals were lame
  • At day 23, 8 animals lame animals tested PCR positive for D nodosus, 11 animals with 'warm feet' (not mentioned in the methods) tested PCR negative for D nodosus; 6 months later 5 animals lame tested PCR negative for D nodosus
  • Danish flocks:
  • Of the 48 flocks where one or more of a selection of 8 sheep tested PCR positive for D nodosus initially, 44 converted to being PCR negative when 8 animals were tested more than one year later
  • It was stated that a few individual sheep developed transitory injection site reactions, but the number of these was not mentioned
Study Weaknesses:
  • The study is a descriptive case series, and prone to substantial bias
  • It is not clear how the outcomes were measured, particularly the scoring systems for lameness and footrot lesions
  • Few details were given in relation to the adequacy of the sampling regime
  • Further methodological details are required to be able to repeat the study
  • It is not stated as to whether the study received ethical approval or not
  • The total number of sheep (denominator) at each time point measured across the study is not given
  • It was stated that a few sheep developed transitory injection site reactions, but the number is unknown
  • The manufacturers of the product used in the study funded the study and the primary author at the time of writing was employed by the company
Attachment:
Evidence appraisalEvidence appraisal

Comments

The use of gamithromycin in sheep is currently not licenced in the UK and with other preparations available that are licenced to treat footrot in sheep, should not be used under the cascade. 

Additionally, the way in which footrot affects flocks in Denmark and Germany is likely to be different to how footrot as an endemic disease affects flocks in the UK.

For good antimicrobial stewardship, therapeutic (not blanket treatment) antimicrobial use should always complement other preventive practices, such as good farm hygiene and biosecurity (RUMA 2005).

Bottom line

There is not enough good quality evidence to suggest that whole sheep flock treatment with gamithromycin will reduce the prevalence of footroot.

Disclaimer

The BETs on this website are a summary of the evidence found on a topic and are not clinical guidelines. It is the responsibility of the individual veterinary surgeon to ensure appropriate decisions are made based on the specific circumstances of patients under their care, taking into account other factors such as local licensing regulations. Read small print

References

Forbes AB, Strobel H, Stamphoj I, (2014). Field studies on the elimination of footrot in sheep through whole flock treatments with gamithromycin. The Veterinary Record 174: doi: 10.1136/vr.102028.

About this BET

First author:
Marnie Brennan
Second author:
Zoe Belshaw
Institution:

CEVM, University of Nottingham

Search last performed:
2016-11-22 17:21:23
Original publication date:
2016-11-29 17:21:23
Last updated:
2016-11-29 17:21:23
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