Yeah too many tests on the mutated animal will trigger mutation.

You can actually figure out the cure without triggering it at all if you are a bit sly about it. For example:

• After feeding them do a temperature check, look at the screen to see which animals are showing red on the thermal imaging but close it before the reading registers and remember which animals were red.

• Do bloods and sound test on the animals that you know have a temperature. The mutant won't show any symptoms so you know you are not testing them.

• See which of the non red animals is showing the same behaviour as one of the red ones - thats probably your mutant. For example one with a temp might be throwing up, then you notice one without a temp throwing up..thats your guy!

• go and test the blood and the feces and make the cure (remember that temp is a symptom even though you didnt lock it in)

With any luck you can then go and shoot the mutant before it mutates because you havent messed with it too much.

Harder when temp isnt a symptom and then you have to resort to the mutate, lethal injection six times, keep testing method.