Thrush is a bacterial infection. My daughter had it when she was born. If you're refering to a baby/child, it is a very thick film on their tongue. A pediatrician will prescribe a medication for her/him and you need to take a nipple brush to the inside of their nipples. Dishwashers do not get rid of it, you need to scrub them by hand every use. My childrens pediatrician said that's how the nipples and bottles need to be done no matter what or they are susceptible. I went further and also brushed my childs tongue with a baby brush which helped as well.
Hope this helps!
All sorts of different things including a cheese like discharge from your vagina. It may be red and itchy as well.