It is a type of infective endocardium that results from direct infection by bacteria, fungi, viruses, rickettsia, chlamydia, etc. The onset of the disease is slow, with generalized malaise, malaise, low-grade fever, and weight loss as nonspecific symptoms. Fever is the most common, with an irregular fever pattern and may also be characterized by tachypnea or intermittent fever, accompanied by sweating and coldness, and a body temperature of 37.5-39 degrees Celsius, or more than 40 degrees Celsius, or only a low fever. Anemia is another common symptom, 70% of patients have progressive anemia, mainly related to infection and suppression of bone marrow. Another manifestation is pain, mainly joint pain, low back pain and muscle pain.