Hi J.
I don't know what the laws are over there, but mould like that can be dangerous to health, and certainly not good for such a young child. Do you have access to any environmental health people where you are? I'm sure if they came to have a look, that your landlord could be made to rectify the problem in some way. Meanwhile, there are tins of mould repellent that you can buy. You clean the walls or whatever first, and then paint over with this stuff. Most large DIY places sell it. Try and leave windows open to let out any steam/condensation, and let your baby get out in the fresh air when possible. Also have a word with your health visitor and/or doctor about your baby's condition. x