A medical specialty called infectious diseases focuses on preventing, diagnosing, and treating illnesses brought on by microorganisms like bacteria, viruses, fungi, and parasites. A wide variety of infectious conditions, including bacterial infections (like pneumonia and urinary tract infections), viral infections (like influenza and HIV), fungal infections (like candidiasis and aspergillosis), and parasitic infections (like malaria and giardiasis), can be diagnosed and treated by infectious disease specialists, also known as infectious disease doctors. By researching infection patterns, keeping an eye on outbreaks, and putting controls in place to stop the spread of infectious illnesses, they play a critical role in promoting public health.