Except that entire incident made no sense with the established rules of morphing.
For example, how can Ax have gotten sick while in human morph? His traia gland obviously isn't part of the human body, it should have been in Z-Space, yet Ax first manifests symptoms at a school dance.
Next example, why does demorphing/remorphing not remove the disease? From what we know, yamphut is a medical complication when the gland collects too much disease organisms. Said disease organisms are by no means genetic, and they should have left the body whenever Ax morphs/demorphs, since they don't originate from Ax in the first place. But Ax remains fevered despite demorphing to andalite. This seems to imply that the problem is genetical (since morphing heals injuries from DNA) rather than acquired (which yamphut is explicitly said to be)
Also, just to point out something, the traia gland never bursts. If it bursts, said andalite dies, since the disease organisms are released into the body, and more importantly, is directly behind the brain, indicating that it would be the first affected organ.
Also, if Ax had yamphut, what he was suffering would be due to the inflammation of his traia gland; the disease is by no means 'contagious'. This would be like suffering from appendicitis and subsequently making everyone else around you sick. For the four animorphs to get sick means that whatever affected them had mutated to affect humans... and hawks. This would be a super virus, and more importantly, it would have affected everyone else around the animorphs. Rachel's mom, her two sisters, Jake's entire family, Marco's dad. And they would spread it to everyone else they'd meet, and you'd get an epidemic.
More importantly, it is confusing because yamphut seems to affect only one person (Ax. You need a traia gland to suffer from it). Of course, there is a plausible explanation, in that Ax was suffering from yamphut, yamphut being a symptom. What Ax is actually suffering from (as well as the animorphs) is an unknown disease, however the only reason As would die from it is because said disease is being contained by his traia gland, which is being worked to death and is about to rupture as a result. The animorphs however, get sick since they don't have such a gland to do work for them.
It raises a lot more questions than it answer, though it would explain the reason why an inflammatory condition can affect 3 kids and a bird.
It still wouldn't answer how demorphing/remorphing doesn';t fix it (and because Ax promptly regrows his Traia gland the next time he morphs and demorphs). If the problem was really the traia gland and not some unknown disease, Ax doesn't actuall solve the problem, since the problem is with his traia gland (ie. genetic) and that eventually it's going to happen again. Since it never does however, it backs up the theory that it wasn't his traia gland that caused him, 3 kids and 1 bird to get sick. It was another disease, which
we are never told where Ax had gotten from. (maybe at the school dance? spiked punch?)
I'm not buying the green box theory, or the purple box theory (though there IS a pruple box, which was used to contain a certain visser) partially because it was never established, and is a little bit too convenient. ("The aliens have morphing technology; OF COURSE THEY HAVE ADAPTATION TECHNOLOGY")
Not to mention, Seerow's Kindness was explicitly giving the yeerks portable kandrona generators. That was it.
You could argue that Visser 3 never gets it because lo and behold, he's Visser 3 with a large amoun of resources. Even if he needs a special daikyu radish that is only grown once every two years to cure his traia gland problem, he'd get it.
The Hork Bajir being immune to disease of Earth is unlikely, considering how the Arn would have to be super knowledgeable on earth disease, and be able to cure an entire species working for them against it, implying they expect their hork bajir to someday reach a planet with this disease. Unless there were generations of inbreeding the seers, this wouldn't happen.
Arn #1: "Hey, Arn #2, should we inoculate them against disease from a planet called Earth roughly millions of light years away?"
Arn #2: "Sure, arn #1, wouldn't want our Hork bajir getting sick when they head to earth for a vacation." *playful punch*
Arn #1: "Oh, you." *laughs*
Arn #2: "I try, I try." *kisses Arn #1*
Arn #1: "..."
Arn #2: "... too soon?"
But in any case, my original purpose was just to point this out. Having done that, I shall let this topic rest.
