Background“Brachyspira hampsonii”, discovered in North America in 2010 associated with dysentery-like illness, is an economically relevant swine pathogen resulting in decreased feed efficiency and increased morbidity, mortality and medication usage. “B. hampsonii” clade II strain 30446 has been shown to be causally associated with mucohemorrhagic diarrhea and colitis. Our objectives were to determine if “Brachyspira hampsonii” clade I strain 30599 is pathogenic to pigs, and to evaluate the relative diagnostic performance of three ante mortem sampling methodologies (direct PCR on feces, PCR on rectal GenoTube Livestock swabs, Brachyspira culture from rectal swabs). Five-week old pigs were intragastrically inoculated thrice with 108 genomic equivalents "B. hampsonii" (n = 12), or served as sham controls (n = 6). Feces were sampled and consistency assessed daily. Necropsies were performed 24 h after peak clinical signs.ResultsOne pig died due to unrelated illness. Nine of 11 inoculated pigs, but no controls, developed mucoid or mucohemorrhagic diarrhea (MHD). Characteristic lesions of swine dysentery were observed in large intestine. “B. hampsonii” strain 30599 DNA was detected by qPCR in feces of all inoculated pigs for up to 6 days prior to the onset of MHD. The organism was isolated from the feces and colons of pigs demonstrating MHD, but not from controls. B. intermedia was isolated from inoculated pigs without MHD, and from 5 of 6 controls.ConclusionsWe conclude that “Brachyspira hampsonii” clade I strain 30599 is pathogenic and causes mucohemorrhagic diarrhea and colitis in susceptible pigs. Moreover, the three sampling methodologies performed similarly. GenoTube Livestock, a forensic swab designed to preserve DNA during shipping is a useful tool especially in settings where timely transport of diagnostic samples is challenging.

The role of N-myristoyltransferase and calcineurin is well established in signaling pathways. However, there are no data on their expression and activities in normal and inflamed lungs. The mechanisms of lung inflammation induced following administration of lipopolysaccharides (LPS) or exposure to swine barn air remain unclear. Therefore, we examined expression and activities of N-myristoyltransferase and calcineurin in normal and inflamed lungs of rats. Histopathology showed acute inflammation in the lungs of rats exposed to barn air or LPS but not of control rats. There was no difference in the activities of N-myristoyltransferase and calcineurin among the control, barn-exposed, and LPS-treated rat lungs. Although N-myristoyltransferase and calcineurin were localized in airway epithelium, blood vessel walls, alveolar macrophages, and septa in the lungs of rats from all the groups, the staining intensity was increased in the lungs from rats exposed to intravenous LPS or barn air. Densitometric analyses of Western blots of 55- and 60-kDa polypeptide bands corresponding to N-myristoyltransferase and calcineurin, respectively, in the lung homogenates revealed no differences among the groups. These results show that expression of myristoyltransferase and calcineurin in lung epithelium and endothelium and a cell-specific increase in immunohistochemical expression.