Decreases seen in B, T, and natural killer (NK) (singlets+live+CD45 + CD3-CD20-CD14-) cell populations in animals with acute illness that met endpoint criteria for euthanasia were followed by slight increases and a rebound at the terminal phase of disease (those with NiV-M infection); similar activity was seen survivors but not evident in animals exposed to NiV-M that remained uninfected. Here, CD14 is linked to infection.