29 October 1999

Lab find might help DD battle

FINDING the organism responsible for digital dermatitis in UK dairy cows and growing it in the lab should help develop disease prevention and treatment strategies.

Ibraham Demirkan, from the University of Liverpool, reports in the Vet Record, Oct 23, that an un-named spirochaete type bacteria has been found and grown, in his MAFF-funded research. The sample came from a cow in Cheshire with a typical UK digital dermatitis lesion.

Bob Ward, from the universitys vet school, adds that being able to grow the organism will help identify more about what it is and how it lives.

Knowing more about the spirochaete may help find ways to reduce spread between cows.

"No herd in the UK has managed to eradicate DD once infected." And various treatments are still being tested for the disease, he adds.

But according to another recent study, 20 times more cases of DD occur in cows hind feet than in front feet. Normally DD occurs where skin meets horn, typically 2.5cm (1in) off the ground for hind feet and 3.3cm (1.5in) for front feet. Front feet, therefore, may stay out of slurry, a possible host of the organism, better reducing infection risk.

He believes this shows it is worthwhile providing a clean and dry environment, and trying to keep cows feet out of slurry.

"In the much longer term, it is possible that a vaccine could be developed. But because cows can be re-infected, it may be difficult to produce immunity to DD."

But different strains of spirochaete could be responsible for DD in other countries and in the UK. "The DD organism found in Germany recently was a different strain and so is the one in the US." &#42