Creatures Caves

How realistic are they? From just looking at genetics and chemical levels, there are some baffling things about sickness... how do antibodies work? They don't seem to directly reduce antigens, and the level of antibodies don't seem to affect how quickly antigens go away, so why do creatures produce them? What about other toxins and histamines, where do they come from? What are the effects of coughing and sneezing? How does illness spread? Why do certain chemicals and toxins appear some times and not others?

On the surface, creatures immune systems and the behavior of infections don't seem to make much sense, but it really is a lot more elegant and realistic than it seems, because of another factor which makes up a large piece of that puzzle that is effectively invisible... bacteria. Bacteria are invisible cobs that are randomly placed occasionally by the game, which represent infectious agents, and can sit around and attach themselves to creatures and objects and inject antigens and toxins. If floating around or on an object, they can either attach or copy themselves to any passing creature.

In creatures, there are effectively 8 families or types of infection, each with effects in common (representing separately things like pneumococci, streptococci, spirococci, staphylococci, influenza strains, etc...) These families each have their own unique set of effects they have in common, which are represented by the 8 antigens, so all types of flu might make antigen 1 for example, all pneumococci might make antigen 0, all staph antigen 2, etc... this is actually pretty realistic, as closely related bacteria tend to affect the same parts of the body, have similar symptoms, and usually take similar amounts of effort for the body to fight off.

Antigens can be thought of as representing the level of symptoms of a particular type of infection, and each type has their own unique effects on creatures' bodies, determined by genetics... like making the creatures feverish or cold, making them tired, making their bodies release histamines, interfering with other reactions in their bodies, etc... The antigens being in the system also trigger the body's immune system response to that family of bacteria, which is to use extra energy to process and slowly break down some of the antigen into matching antibodies, which in real animals act like a key that specifically fits into a particular species of bacteria's proteins, breaking them down and killing them...but for creatures, these antibodies seem to have no chemical effect in their bodies at all and there are only 8... huh?

But antibodies actually do have the same ultimate effect in creatures... when they reach a high enough level, they kill that type of bacteria cob... stopping it from making new antigens and toxins, letting the antigens and toxins in the body decay so the sickness starts to slowly go away, just like getting over a real illness. Even without the bacteria cob on them, as long as a creature has that antigen in their systems, they can still be considered to have some level of that illness in them (but the symptoms weaken as the antigen level goes down and they aren't infectious any more)... A similar thing happens in real animals... antibodies take time and energy to create, and need to build up to a certain 'tipping point' before they can start to overcome an infection, and then the symptoms begin to go away gradually as the infection is actually fought off by the body.

In creatures, the different antibody numbers don't actually mean individual antibody strains... they really just represent different TYPES of immune responses, like fighting a flu vs a respiratory infection vs a blood infection... that's why some are produced slower than others... Their rate of production represents how quickly the body fights off different broad types of infection, but they don't represent immunity to any particular strain other than the specific bacteria they are currently infected with.

This is why it's realistic that a creature can get a new antigen 1 infection even after having made antibody 1 before, because the next time they get antigen 1, it's not from the same exact strain of bacteria, just a related one... This is how the flu works in reality.. even with vaccines or antibodies for one strain, the flu mutates each year making new strains... so each time you are exposed to a new strain, it might have similar symptoms, but the body still has to make a whole new set of flu-killing antibodies each time to kill it.

What about histamines? Why would creatures produce them if it just spreads the disease? Histamines don't seem to help them at all if you look at what they do chemically or genetically, which is just make them cough/sneeze... What's the point? That's explained also in the bacteria themselves, and has a solid basis in reality... When the host coughs or sneezes, bacteria have a chance to copy themselves and attach to other nearby creatures or objects (spreading the sickness), but also have a small chance to be expelled from their host (which is also realistic, and one reason why real animals produce histamines in the first place). If other sick creatures are around, there's a good chance they will just be reinfected after coughing out the bacteria, but it is still another way creatures can start to get better more quickly (or even get rid of an illness before it fully takes hold).

Bacteria also evolve and mutate on their own, making them produce any of a certain range of chemical toxins on top of their family's common antigen, making a large variety of effects possible, even among related strains of bacteria... They can even mutate and change their properties to release a different antigen too... Antigen mutation means they now have a different set of symptoms, and the bacteria becomes vulnerable to a different type of response because its now similar enough to another type of infection for that kind of response to kill them.

All in all, when you look at the whole picture, you end up with a fairly accurate, if simplified, representation of how real infectious agents and immune responses work, with different broad types of infections, that have symptoms in common, but can evolve a large variety of possible additional symptoms, and the creatures have the ability to evolve countless new types of immune responses and reactions to practically every strain. They can even form a symbiosis or carrier relationship with any of hundreds of unique infections, any of which can mutate and change on their own to make many new and more (or less) dangerous infections.