Immunity and Disease
As if poisons weren't enough, there are bacteria floating around on board Capillata that your Norns can catch disease from. These bacteria are capable of breeding and mutating, changing in numbers and disease severity over time. The symptoms of disease are highly varied, ranging from a mild infection that you won't even notice your Norns have had, to diseases that can kill in a few minutes. Therefore, it is important to give your Norns regular check-ups with the HoverDoc, and treat any diseases your Norns catch. To test for disease using the HoverDoc, drop the HoverDoc onto a creature, and then click the right hand arrow to slide out the options panel. Click the little bug-like symbol second from the top. The HoverDoc will then scan the Norn it is currently paying attention to for bacteria. You can also scan the immediate area for bacteria by pressing the magnifying glass, and kill them off using the symbol of a bug with a cross over it. The containment area can also make bacteria visible and kill them off using similar sprays. When made visible, bacteria appear as little yellow dots. If you see one follow a creature around, it is likely that creature has an infection of some kind.
When a bacteria is infecting a Norn, it injects it with one of eight different antigens, named antigen 0 - antigen 7. Some of these antigens react with the Norn's biochemistry, producing toxins such as the histamines. All the antigens can affect long term health by causing withering of the Norn's internal organs. However, this only becomes a problem if a Norn has many infections during its lifetime, so don't panic! The antigens have a good effect, too. They stimulate the Norn's immune system to produce one of the eight antibodies, appropriately called antibody 0 - antibody 7. These will eventually fight off an infection, even if it is not cured by the containment area or the HoverDoc first.
The bacteria themselves can also inject toxins into your Norn's bloodstream. If you find a Norn with an odd case of poisoning, the chances are it has had an infection at some point. Since the bacteria evolve, you never know what symptoms a disease will cause.