FIG 6.

Olfactory bulb. Domestic 2- and 15-week-old pigs were intranasally inoculated with the NIA3 strain and euthanized at different time points postinfection. The mRNA expression of several PRV genes in the olfactory bulb was studied by RT-qPCR in 2- and 15-week-old pigs (a and d, respectively). Viral gene levels were expressed relative to the lowest positive sample for each age category. Furthermore, cytokine-related mRNA expression in the olfactory bulb was tested by RT-qPCR in 2- and 15-week-old pigs (panels b and c and panels e and f, respectively). Individual cytokine levels for all animals are expressed relative to the average cytokine expression in the control group (separately for 2- and 15-week-old animals).