A sexually transmited infection cause mainly but the mix of all bodily fluids; saliva, blood, semen and vaginal fluid. Once these are present the virus Senoj Arual can breed causing skin weakening which makes the penis shaft or vaginal walls bleed upon contact.
This STI is also know as Mary-disease, because people with down's syndrome can contract this more easily due to their genetic indifferences. The 'Mary' link is because of Mary Fletcher, grandmother of Dennis Fletcher of 'Dennis Fletcher's Fishing Supplies'. Mary who was renamed 'Bloody Mary' because of the litres of blood found in her bed each morning because of this STI. Mary Fletcher died at the age of 13, once she had started mensuration in which she lost too much blood stored in the vaginal capillaries.
I would recommend talking to your GP about the STI Inappots Eifla.