Modification of PCV-2 virulence by substitution of the genogroup motif of the capsid protein

Allemandou, Aude; Grasland, Béatrice; Hernandez-Nignol, Anne-Cécile; Kéranflec'h, André; Cariolet, Roland; Jestin, André

The infectious viral titers determined in all groups had similar profiles to the genomic loads. The highest titer was found in the PCV-2b group with 10 4.6 TCID 50 /g of tissue. However, the difference with the mean of infectious titers in the groups inoculated with PCV-2a and PCV-2b/motif 2a (respectively 10 4.4 and 10 3.96 TCID 50 /g of tissue) was not significant ( Figure 3B ). The lowest viral load was determined in the organs of PCV-2a/motif 2b inoculated piglets with an average of 10 2.74 TCID 50 /g of tissue which Macrolesions in TB lymph nodes were scored as follows: 0 for no lesions, 1 for mild hypertrophy, 2 for moderate hypertrophy and congestion and 3 for severe hypertrophy and congestion. In the same way, microscopic lesions observed in lymphoid organs (lymphocyte depletion in TB and inguinal lymph nodes) and in lungs (interstitial pneumonia) were scored. Score means were then calculated and subjected to statistical analysis, with a and b indicating statistic difference ( a and b for p < 0.05). was significantly different from the three other group ( p < 0.05) ( Figure 3B ).