Symptoms: the body temperature usually rises to 40-42 degrees, anorexia, chills, constipation and diarrhea alternate, purple spots appear on the lower abdomen, nose mirror, ear tips and inside limbs, finger pressure does not subside, and bleeding spots can be seen on cornea and mouth. Anatomy shows lymphedema, hemorrhage, marble-like lesions, yellowish kidney, needle-like bleeding spots on the body surface, bleeding spots and spots on the serosa, heart, bladder, gallbladder and tonsil of the whole body; There is dark purple at the edge of the spleen, and hemorrhagic necrosis is prominent on the surface. Some have button-shaped ulcers in the ileum, cecum and colon.