A bacterial infection does not necessarily mean that the home is too dirty. Whether a bacterial infection can occur is a combination of an individual’s immunity and the specific circumstances of the bacteria. If the bacteria themselves are not infectious, they will not usually lead to infection, no matter how dirty the home is; whereas when the bacteria are virulent, or numerous, infection can occur when the body’s immunity is reduced or is not strong enough to fight them, so it is not possible to generalise. In addition, bacteria are not visible to the naked eye, and a dirty living room may be dusty, and an individual cannot be directly equated with a bacterial infection even if they are ill.