VIP and infection: Similarly, the mitochondrial transmembrane potential was reduced by 50% or more at both day 10 and 14 post infection (p<0.001, Fig 5E), and VIP treatment for day 5–10 alleviated the reduction at both time points (p<0.05, Fig 5E), whereas treatment for day 10–14 or 5–14 was less effective (Fig 5E).