Detectability and prevalence of Brachyspira species in herds rearing health class feeder pigs in Finland

Faeces samples were taken three times at two-week intervals, from the farro wing units of four herds of known Brachyspira (formerly Serpulina) status a nd one of unknown Brachyspira status. Brachyspira hyodysenteriae, Brachyspi ra pilosicoli, Brachyspira intermedia and Brachyspira group iii were isolat ed from the faecal samples from the weaners in the herds using either a max imum of 50 ppm of olaquindox or no feed additives. The detection rates were relatively consistent. However, B hyodysenteriae was not detected at one s ampling in a known positive herd. The prevalence of Brachyspira species was also studied in feeder pigs originating from LSO 2000 health class farrowi ng units, comparable with specific pathogen-free herds. These farms were fr ee from swine dysentery, sarcoptic mange, swine enzootic pneumonia and prog ressive atrophic rhinitis. Fifty of 428 herds were sampled once. B hyodysen teriae was not isolated from any of them, but B intermedia, B pilosicoli an d Brachyspira group III were isolated from five, 14 and 37 of the herds, re spectively. The detection of Brachyspira species did not relate to the prev alence of diarrhoea in the herds, as judged by the farmers. The herds using carbadox (40 to 50 ppm) had a lower prevalence of Brachyspira species than those using olaquindox (40 to 50 ppm).