Dichelobacter nodosus is an obligate parasite of the feet of sheep, which means that it does not survive in the environment for more than a few weeks. This is the principle upon which all methods of control are based: if sheep with the infection can all be identified and either treated or removed, the disease can be eradicated (Beveridge, 1941; Egerton, 1986).
In general, the disease must be controlled before it can be eradicated. Control means that the number of affected sheep is reduced to a low level. Eradication means that all cases of the disease are eliminated and that it does not recur. Surveillance is then required to confirm that eradication has been achieved and is maintained. The means of doing this were summarised by Egerton (1986):
- Destocking – replace entire flock with disease free sheep
- Sell affected sheep to reduce prevalence, confirm control and then eradicate
- Treat affected sheep to reduce prevalence, confirm control and then eradicate
Please refer to the page on Treatment for the options that are available.
An accurate diagnosis of virulent footrot is required in order to justify control and eradication. There is no economic benefit in attempting to control benign footrot. However, there is a diagnostic grey zone with intermediate footrot, where there may be some economic losses and separately in some regions where producers do become concerned about mild, temporary, seasonal lameness, particularly in young sheep; this syndrome is a form of footrot of uncertain economic impact that requires detailed research (see pages on intermediate footrot).
Each farm situation is unique. A control and eradication program does require detailed planning and commitment of resources over the short, medium and long terms. This work should be done in conjunction with an experienced veterinarian. Egerton (1986) noted that “Eradication is an expensive proposition and should not be attempted unless owners and others involved appreciate all of the costs, including labour, which are essential to success” and “successful eradication is also dependent on management factors, like the provision of adequate facilities for handling sheep, full musters for all inspections, sheep-proof fencing and care in the introduction of new stock”.
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Important disclaimer: The advice contained on this website is of a general nature. Please consult your veterinarian or government district veterinarian, animal health or biosecurity officer for an accurate diagnosis if you suspect footrot, and for specific advice on the best course of action to prevent, control and eradicate footrot.