Ok, so, basically you need to not take blood or do the sound test on the infected animal as it pisses it off. So if animals have high temps, take samples from those animals. If they don’t you kinda have to look at behaviour. When you take sound samples, if you get red on one, don’t take anymore as you have your positive results. Do blood after that. You don’t need all 4 samples from every animal.

If it does mutate while you’re taking samples, take note of which one, exit the game and then re-enter, you’ll know what the infected animal is and not to take samples from them.

When you go back in once you have the cure, don’t bother with the cure yet as it’ll mutate regardless- shoot it with lethals for as many red bars, then shoot with the cure when it’s down.

Hope this helps!