Infectious diseases arise from bacteria, viruses, fungi, or parasites and can spread through contact, contaminated food or water, or weakened immunity. Common types include bacterial infections (e.g., strep throat), viral illnesses (e.g., influenza), fungal infections (e.g., athlete’s foot), and parasitic conditions (e.g., malaria). Treatment options include antibiotics, antivirals, antifungals, and antiparasitic medications, alongside preventive measures like vaccinations and hygiene practices. Supportive care, such as rest and hydration, aids recovery. Adopting good hygiene, safe food practices, and vaccinations significantly reduces infection risks.