This would be an interesting feature and would add a new dynamic to the game when dealing with any players. When attacked by a certain type of zombie and hit X amount of times the player will become contaminated. Everything on that player then becomes contaminated and after about 1 hr the players screen will slowly turn yellow and become so yellow that you eventually can hardly see. At this point you soon die. To counter this (similar to the vitamin bottle) there are pills you take(Must take 10 pills and only 5 per bottle max)Once all are consumed the player goes back to normal. Nobody besides that player knows he is contaminated and nobody can tell unless they have a special solution they can add to a players skin or add to any item before moving it to their inventory, if an item is contaminated there will be a large spray bottle full of the solution and spray it down to make it safe to use. Any item thats left in your inventory too long will contaminated the player. When contaminated players are close to others they can spit on them to spread it, spit in water or on food and give it to the bandit that's about to kill you as a final F**k you. :) Special gloves, suits, or items all could be added to further prevent contamination.