Typhoid cells are actually a type of macrophage, which is a specific and characteristic change in the human body after infection with typhoid fever. If a person is infected with S. typhi, there will be a proliferation of macrophages, which appear to destroy S. typhi and engulf S. typhi, and there will be red blood cells and fragments of some cells, so that there will be a proliferation of macrophages that engulf S. typhi. The cells containing S. typhi, typhoid vesicles, erythrocytes, and macrophages are collectively called typhoid cells because they are found in the cytoplasm by pathological histology. Typhoid cells can gather in clusters or in tubes called typhoid nodules. If typhoid cells or typhoid nodules are found in the physical examination, it proves that the body is infected with typhoid fever.