Reproduction of Mucohaemorrhagic Diarrhea and Colitis Indistinguishable from Swine Dysentery following Experimental Inoculation with “Brachyspira hampsonii” Strain 30446

Abstract

"Brachyspira hampsonii" strain 30446 causes mucohaemorrhagic diarrhea in pigs following a 4-9 day incubation period. Fecal shedding was detectable by day 4 post inoculation, and rarely preceded the onset of mucoid or haemorrhagic diarrhea by more than 2 days. Culture and 30446-specific qPCR are reliable methods of detection of this organism in feces and tissues of diarrheic pigs. The emergence of a novel Brachyspira spp., such as "B. hampsonii", creates diagnostic challenges including higher risk of false negative diagnostic tests. We therefore recommend diagnostic laboratories routinely use Brachyspira culture, nox-based and species-specific PCR, and DNA sequencing to diagnose Brachyspira-associated colitis in pigs.