When you have finished always put the lid down on the toilet before you flush, this prevents the airborne spread of contaminated water vapour as the toilet flushes and particles spread over an extended area of many square meters potentially contaminating toothbrushes, soap, surfaces, make up and other bathroom products you would much rather keep clean and protected from such dangerous micro organisms as Ecoli, Pseudomonas, Salmonella, Norovirus.
According to the American Journal of Infection Control flushing the toilet with the lid open produces what is called “Toilet Plume Aerosols” which can contaminate surfaces and can survive for weeks , even months and has been the source of many dangerous outbreaks of Pseudomonas and Ecoli to name but a few. Click Here to Watch a video illustrating this
So in the future it may be a good idea to close the lid of your toilet before you flush and save yourself the risk of tummy upsets or even worse.