Origin, Evolution, and Virulence of Porcine Deltacoronaviruses in the United States

Ma, Yuanmei; Zhang, Yu; Liang, Xueya; Lou, Fangfei; Oglesbee, Michael; Krakowka, Steven; Li, Jianrong

Pig challenge, sampling, and tissue collections. After virus challenge, the piglets were observed and evaluated daily for body weight and temperature changes and clinical signs of PdCV infection. Daily rectal mucosal/fecal swabs were collected from each piglet for virus detection. A diarrhea/fecal consistency score was assigned to each using a subjective scale wherein 0 is normal, 1 is pasty, 2 is creamy, and 3 is watery. Pigs with fecal consistency scores of 2 or 3 were scored as diarrhea-positive. Prior to termination, a blood sample for serum was collected from heavily sedated piglets; each piglet received Euthol solution intravenously to effect. Intestinal contents from the duodenum, proximal jejunum, ileum, transverse colon, spiral colon, and descending colon were collected from each pig. Whole blood and serum were collected first postmortem, followed by collection of duplicate tissues for RNA analysis and histological examination. The tissues sampled were glandular stomach, duodenum, proximal jejunum, distal jejunum, ileum, cecum, spiral colon, terminal colon, spleen, liver, kidney, and lung.