Pathogenic yeasts are a type of fungus that can cause infections in humans and animals. The most common pathogenic yeast is Candida albicans, which can lead to conditions like thrush and yeast infections. These organisms thrive in warm, moist environments and can become harmful, especially in individuals with weakened immune systems. Another notable pathogenic yeast is Cryptococcus neoformans, which can cause severe respiratory infections and meningitis. This yeast is often found in soil and bird droppings. Pathogenic yeasts can be particularly dangerous for people with compromised immune systems, such as those with HIV/AIDS or undergoing chemotherapy.