Final answer:
Oral thrush is a fungal infection caused by Candida overgrowth in the mouth. It affects infants and immunodeficient patients. Treatment options include topical and systemic antifungal medications.
Step-by-step explanation:
Oral thrush is a fungal infection caused by overgrowth of the yeast Candida in the oral cavity. It is characterized by the appearance of white patches and pseudomembranes in the mouth. Oral thrush is most common in infants and immunodeficient patients, including those with AIDS. The infection can be treated with topical or systemic antifungal medications, depending on the severity.