However, if an individual is sick with something and currently shedding out large quantities of an infectious virulent pathogen (virus or bacteria) in their urine, feces or vomitus, this dynamic completely changes.
A 2024 study empirically disproved this theory, illustrating that the viruses that toilet plume contains still spread out the gaps in the seat onto the walls and concentrating on the surrounding floors.
[2] There is evidence that toilet aerosols generated by flushing can be a vector for diseases that involve acute gastroenteritis with the shedding of large numbers of pathogens through feces and vomit.
[7] The feces and vomit of infected people can contain high concentrations of viruses & bacteria many of which are known to survive on surfaces for days, weeks or even months.
Some other pathogens speculatively identified as being of potential concern for these reasons include gram-positive MRSA, Mycobacterium tuberculosis, and the pandemic H1N1/09 virus commonly known as "swine flu".
[7] The critical size dividing these dispersal modes depends on the evaporation rate and vertical distance between the toilet and the surface in question.