There was sudden blood on the sheets, and I didn't have any wounds. What happened?

1. Wound bleeding is negative pressure, so it is difficult for body fluids to enter your blood from the negative pressure of the wound. I wonder how long the liquid on the sheets has been exposed to the air. You need fresh body fluids to infect. 3. The route of blood transmission refers to the use of needles and blood transfusion. If you want to contact body fluids through a wound, your wound should be large enough to see a doctor immediately, or a wound that has just undergone major surgery.