20 years ago erysipelas was a rare disease in laying hens in Sweden and other countries, but since 1998 outbreaks have hit Swedish laying hens every year. In several other countries in Europe a similar trend is seen and it seems to be a link to the fact that hens nowadays are held floor systems. Organic farms seem to have a particularly increased risk for the disease.
Assistant state veterinarian Helena Eriksson (SVA / Inst f Clinical Sciences SLU) defended on May 31 her thesis on erysipelas in laying hens. It is the bacterium Erysipelothrix rhusiopathiae causing the disease erysipelas. The disease is well known in pigs, but many other mammals and birds can also suffer from it.
In one of the included studies, six organic laying hen herds were examined. Four of these farms had on-going erysipelas breakouts while the hens on the other two farms were healthy. Samples were taken from the hens and the environment on the farms. The bacteria were found in samples of intestinal contents from hens, manure, dust and water dispensers in the affected herds. It was not, however, possible to detect any erysipelas bacteria in the samples from the healthy herds.
One conclusion is that above all, manure, but also dust, from erysipelas infected flocks may spread the infection. This suggests that infection occurs at the same time from a single source of infection from outside, and that the bacteria then spreads through the flock.