Idiots guide to spreading germs!
1) take a number of organisms which spread germs through droplet infection. (Sneezing and coughing etc.)
2) Sit them close together in confined space. (sealled aluminium tube is ideal). Try not to let them move freely.
3) Pump droplets through enclosed space.
4) Add stress to said organism by pressurising cabin to 8000feet. Try feeding alcohol and coffee to dehydrate organism.
AVOID FRESH AIR AT ALL COSTS.
Excuse the sarcasm, it is after all Monday morning.
PS Conjunctivitis is usually self limiting, depending on the cause. Go and see your doc if its not cleared up in 4-5days.