Related Clues:
- Major WWI killer
- Cause of many a sick day
- Wintertime ailment
- Reason to stay in bed
- ___ vaccine
- Reason for a shot
- Reason to take a sick day
- Sick-day cause
- It may be avian
- Pandemic disease of 1918
- Bug with its own season
- Yuppie ___ (chronic fatigue syndrome)
- Pandemic of 1918
- Bug that leaves you weak
- Bug with two homonyms