Pathogenic fungi are types of fungi that can cause diseases in humans, animals, and plants. They can enter the body through the skin, respiratory system, or other routes, leading to infections. Common examples include Candida, which can cause yeast infections, and Aspergillus, which can lead to respiratory issues. These fungi thrive in various environments, often in warm and damp conditions. Some pathogenic fungi are opportunistic, meaning they primarily affect individuals with weakened immune systems, such as those with HIV/AIDS or undergoing chemotherapy. Understanding these fungi is crucial for prevention and treatment of fungal infections.