Infectious disease symptoms can vary widely depending on the type of infection. Common signs include fever, fatigue, cough, and body aches. Some infections may also cause gastrointestinal issues like nausea, vomiting, or diarrhea. Symptoms can appear suddenly or develop gradually, and their severity can range from mild to severe. Infectious diseases can be caused by various pathogens, including bacteria, viruses, fungi, and parasites. Early detection and treatment are crucial for managing symptoms and preventing complications. If symptoms persist or worsen, it is important to seek medical attention for proper diagnosis and care.