13 December 1996

Vets verdict on salmonella

MINIMISING the risk to farm animals – particularly cattle – and humans from a multiple antibiotic-resistant strain of salmonella will depend on better management.

So says a report by Sarah Evans and Robert Davies of MAFFs Central Vet Lab in the Veterinary Record, Dec 7, 1996.

The infection affected more calves than adult cattle, and was fatal in 40% of cases, although more calves than adult animals died. And in 20% of cases, affected farms reported associated illness in farm staff or families.

The report says producers should reduce the risk of infection by purchasing replacement stock from direct sources rather than dealers; buying from dealers increased risks fourfold. Newly purchased animals should also be quarantined for four weeks, say the authors.

Sick animals should be restricted to a dedicated isolation area. Infection risk was found to be worst where cows were calved in buildings which had previously housed diseased stock.

Preventing cats and wild birds accessing cattle feed stores is also important, and the authors found that a high density of cats on the farm was shown to increase infection risks.

Vaccination stopped sub-clinical salmonella infection in all the herds vaccinated, but in non-vaccinated herds, sub-clinical infection lasted for at least six months.