Diagnosis of Swine Dysentery

Since 2008, there has been an increase in detection of cases of swine dysentery (SD) at the ISU VDL from which either Brachyspira hyodysenteriae or Brachyspira hampsonii were isolated by culture. Both of these strongly beta-hemolytic spirochetes have been extensively studied and are equally capable of producing disease in susceptible pigs (Burrough ER, 2017). Disease expression is strongly influenced by diet, particularly dietary fiber, where certain insoluble fiber types increase susceptibility and certain soluble fibers reduce susceptibility (Wilberts et al., 2014; Helm et al., 2021).

The gold standard for diagnosis of SD is still selective anaerobic culture and speciation is determined by MALDI-TOF (Warneke et al. 2014). At the ISU VDL, antimicrobial susceptibility testing is available for Brachyspira spp. at a cost of $40 and is routinely performed for agents of SD. Ongoing analysis of susceptibility data will help monitor emergence of potential resistance in US isolates.

For epidemiological purposes, whole genome sequencing and analysis is available for agents of SD at the ISU VDL to determine the sequence type of any isolate and for comparative analysis of temporal isolates within systems. Please contact the VDL for more information about this service and for an estimate of cost.

Burrough, ER. 2017. Swine dysentery: etiopathogenesis and diagnosis of a reemerging disease. Vet Pathol 54(1), 22-31.

Helm ET, Gabler NK, Burrough ER. 2021. Highly fermentable fiber alters fecal microbiota and mitigates swine dysentery during Brachyspira hyodysenteriae challenge. Animals 11:396.

Warneke HL, Kinyon JM, Bower LP, Burrough ER, Frana TS. 2014. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for rapid identification of Brachyspira species isolated from swine, including the newly described "Brachyspira hampsonii". J Vet Diagn Invest 26(5):635-639.

Wilberts BL, Arruda PH, Kinyon JM, Frana TS, Wang C, Magstadt DR, Madson DM, Patience JF, Burrough ER. 2014. Investigation of the impact of increased dietary insoluble fiber through feeding of distillers dried grains with solubles (DDGS) on the incidence and severity of Brachyspira-associated colitis in pigs. PLoS One 9(12):e114741.