Adjusting How Wolves Contract Illnesses

I used the search tool and couldn't find a suggestion quite like the one I was thinking about.

So what's my idea? I would like to see adjustments to the way wolves contract illnesses.

But what's wrong with the current system?

The current system is flawed, and recently there's been some users taking advantage of it being flawed. When wolves contract one illness they are immune to all others. So when a wolf contracts an illness that is non-lethal and doesn't hurt a wolf's job, it is kept so that wolf can do things that would otherwise be an illness risk. Fleas are pretty notorious for this tactic, as they are even contagious! Meaning that someone's entire pack can contract fleas and an herbalist will become useless. They can't contract anything lethal or restraining as they have fleas! I've even personally seen people selling wolves with fleas in TC to act as a type of, "Patient zero."

So what's the issue with this flawed system?

When a whole pack has a nonlethal and nonrestricting illness, it makes the purpose of an herbalist null. When a lead has said illness it can give an unfair advantage (albeit small) by being able to reap rewards from rolling in poop and licking toads for a long time without having to deal with the risks.

What are ways that this system can be fixed?

Right now I have two ways that this can be fixed to be made less flawed. Each have pros and cons to them as no system can be absolutely perfect, just more user friendly and fair. The first one seems like the more ideal one.

Let illnesses stack aka multiple illnesses

So let's say a wolf gets fleas and it is untreated, they hunt, they return, now they have open wound on top of having fleas. With the herbalist, you can diagnose and treat one at a time. This allows for less to take advantage. However, there are issues. More SC and herbs will have to be used in order to make wolves completely healthy again. If the system isn't thought out well, it could also mean a possibility that lethal illnesses could stack which would equal more HP lost and less time to cure. If no limit is on how many can stack, then wolves can technically contract everything under the sun.

So allow for stacking, but to an extent. Only one lethal can be contracted at a time, and allow for a maximum of 2-3 nonlethal illnesses.

Have illnesses evolve to other illnesses

This one I see more concerns with. Let's say we have a wolf contracts ticks. A real life week passes with no treatment and now the wolf has lyme disease, which is a restricting illness that would not allow for them to hunt/scout or eat. It would have users less likely to keep a wolf sick because it can turn into something worse. There are also concerns with this. More coding would have to be brought in, and more illnesses would likely have to be made. It also makes the possibility for lethal illnesses much higher as new ones will likely be made for this system. 

Any ideas to further help the broken illness system is welcome. If no support, please explain why other than, "I don't like this because I want to roll in poop/not have an herbalist."

Support. We really should have a way to prevent people from taking advantage of the illness system.

Support!

It doesn't make sense that eg. having fleas make you immune to influenza. Also, illnesses stacking up would give a new meaning for "cure all". 

Oh! I didn't even think about the effects of the cure all. It would make that item even better.