Experimental infection of piglets with a korean strain of porcine epidemic diarrhoea virus

Abstract

Thirty colostrum-deprived piglets aged 1 day were inoculated with a Korean strain of porcine epidemic diarrhoea virus (PEDV). The purpose was to elucidate the pathogenicity and viral distribution in PEDV-infected piglets over a period of 60 h, by morphometric analysis, in-situ hybridization and immunohistochemistry. At 24-60 h post-inoculation (hpi), the villous height/crypt depth (VH/CD) ratio of infected pigs was significantly less than that of control pigs. Positive cells typically exhibited a dark black reaction product (in-situ hybridization) or brown reaction product (immunohistochemistry) in the cytoplasm, without background staining. PEDV nucleic acid and antigen were detected in the duodenum, jejunum and ileum of experimentally infected pigs. The results suggested that the Korean strain was virulent and caused severe villous atrophy in the small intestine.

Fig. 1

Jejunum from a piglet dosed orally with PEDV; 36 h post-inoculation (hpi). PEDV nucleic acid (dark black reaction product) was detected in the villous enterocytes. In-situ hybridization. ×200.

Fig. 2

Jejunum from a piglet dosed orally with PEDV; 48 hpi. PEDV antigen (brown reaction product) was detected in the villous enterocytes. Immunohistochemistry. ×200.