To infect with flu the mouse must be deeply unconscious so that the gag reflex is suppressed. If the mouse begins to come around then use additional avertin (0.1ml) to boost anesthesia and insure that the mouse is completely unconscious. This procedure should be carried out only in a approved area for working with FLU virus.
1. dilute flu virus so that it is at a concentration where the desired number of PFU of virus are in 50 μl of PBS. 2. Anesthetize mice (no more than 2 at a time due to length of process) and check for deep sleep (slow breathing). 3. collect 50 μl of virus in p200. 4. lift mouse by scruff gently and hold upright. 5. Add flu dropwise to the nose holding mouth shut between drops and leaving sufficient time for mouse breathing to recover to normal between drops. Note if the mouse stops breathing immediately free mouth and gently tap/massage chest to get breathing again. 6. Place mouse back in cage to recover. 7. Clean hands and procedure area with quatricide to kill off any contamination virions.
Equipment: p200 and tips, FLU in PBS at conc for 50 μl per mouse, quatricide to clean area used, absorbent pad to work over.