In this video guide I will show you how to manually cure a dinosaur or reptile of a disease. This can be done early on in the campaign. Once a dinosaur is sick with a treatable disease you will be given requirements before researching the cure. An example would be for E. Coli you need to separate the sick dinosaur into a separate pen for a minute. Then you can research the cure. Once you have the cure just use the med truck to manually drive in the pen and use the dart gun to shoot the cure into the dinosaur.
You may need to change from the scanner to the dart gun before using it as well. Also may take a few dinosaurs to cure before the achievement pops. Mine was either laggy, or took a couple dinosaurs. Once the dinosaur is cured by you doing it yourself, the achievement will pop.