<qa>  What is the proxy of the environment?2a Factors related to the procedure Compliance to disinfection guidelines prior to performing TVS Rank of procedure since last daily midlevel disinfection Presence of HPV on the ultrasound machine key board, a proxy of the environment 2b Factors related to the center in which TVS is performed Compliance to daily disinfection guidelines Traceability of the disinfection processes Type of center emergency clinic planned sessions obstetrics gynecology IVF monitoring 3 - To estimate the incidence of probe cover rupture and of visible probe contamination by bodily fluids 4 - To model the cost effectiveness of strategies of disinfection 