Low occurrence of Brachyspira -hyodysenteriae in Swiss pig herds with diarrhoea

In the Swiss pig population, only four sequence types (ST6, ST66, ST196, ST197) of Brachyspira ( B .) hyodysenteriae , an agent of Swine Dysentery (SD), have been so far detected suggesting a limited number of sources of B. hyodysenteriae in the Swiss pig production. A one year culture- and molecular-based diagnostic project was performed to identify and trace back B. hyodysenteriae in pig herds with SD, and to identify possible new STs. Up to five faecal swabs from herds with diarrhoea were examined. Three out of 141 herds tested positive for B. hyodysenteriae of ST196 (n=2) and ST66 (n=1). A common source was unlikely as none of the supplier herds or pig trader was shared and the occurrence was very low (2.1%) in the study population. This low occurrence may have resulted from the monitoring and eradications during the last ten years, emphasising their further applications to control B. hyodysenteriae.