Letter From Ada is a file that can be found in Resident Evil 4.
Once a Plaga egg hatches, it's nearly impossible to remove it from the body. But if it's before it hatches, then it can be neutralized by medication.
If it does hatch you might be able to get it out by surgery before it turns to an adult. But it won't be easy. There's a high chance you won't survive the operation.
As far as I know the girl was injected with the egg before you. Her time is ticking. You should prepare yourself for the worst case scenario.
After Leon exits the underground caves, Ada leaves this note to remind him of using the drugs that Luis Sera stole to delay the growth of the Las Plagas inside one's body. The only other solution would be the radiation treatment that may kill Leon and Ashley. It also warns it is only a matter of time before Ashley gets fully infected by the Las Plagas.
- Koichi Hamamura, ed (2006) (in Japanese). biohazard4 kaitaishinsho revised edition. Famitsu. ISBN 4-7577-2638-4.
- Birlew, Dan (2005). Davis, H. Leigh. ed. Resident Evil 4 Official Strategy Guide. Indianapolis: BradyGames. ISBN 0-7440-0346-6.