17th May 2010

New non-chemical treatment to tackle sheep scab

A breakthrough new technique to tackle sheep scab (psoroptic mange) could be on the cards as a result of a Quality Meat Scotland study unveiled this week.

The project was highlighted during a briefing to launch the 2010 Research and Development Report published by QMS which contains information about many of the 47 projects and studentships which the Scottish red meat promotion and development body funds. The report is available to view on line at www.qmscotland.co.uk or by calling 0131 472 4040.

SAC PhD student, Sarah Hall, who is one of 21 post-graduate students working on QMS-funded research projects, explained the sheep scab project could produce an environmentally-friendly alternative to existing chemical treatments for the problem of sheep scab.

Emphasising the impact of sheep scab on the Scottish flock as a serious welfare issue, Ms Hall pointed out that more than 40% of flocks throughout Scotland are affected by the problem.

During the coming year she will investigate the relationship between the bacteria associated with sheep scab and the mites which cause the problem and the extent to which the survival of the mites is affected when these internal bacteria are reduced or altered.

Speaking today (Monday 17th May) Ms Hall said sheep scab used to be considered a winter disease but cases are now being reported all year round.

“Control of the disease is being hampered by reported resistance of the mite to some available products and other environmental side-effects,” she observed.

Among the challenges of the work undertaken so far by Ms Hall has been the construction of chambers to keep scab mites removed from their sheep hosts while they are fed products during the trial work to target and kill potentially beneficial internal bacteria.

“Our results so far indicate that mites fed antimicrobials have much shorter lives than those fed a normal sheep serum diet,” said Ms Hall. While the results are still being analysed preliminary results indicate potential links between bacterial density and survival.

“Once there is a clearer picture of which species of bacteria are present with the sheep scab mites it should be possible to find a type of naturally occurring bacteria-specific virus – known as a bacteriophage - which would selectively kill these bacteria,” said Ms Hall.

The result, she said, could be an environmentally sound alternative to chemical treatments which would only kill a single species of bacteria within the mite and pose no harm to humans or animals.


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