People who often get sick or have poor health probably lead dirty lives. Knowledge about sanitation, bacteria, and cleanliness go a long way to show how a clean environment can mean good health. If a person is able to keep their house clean and in good condition, most diseases will be killed.
I think the term "cleanliness is next to godliness" I imagine that most of the issues can be resolved by just keeping your house and personal space clean,but I think that's just a given. I mean the bacertia and viruses have to start somewhere, just be better if you cleaned up and didn't make your house ground zero.
Yes, I believe that environmentally induced illnesses are caused by poor housekeeping, because with poor housekeeping, germs can stay in the home for later infection. If a bathroom is not cleaned, infections can grow on handles. If food is not cleaned, bacteria can get into food and can infect the people in the family.
I think that poor housekeeping does, in fact, play a role in illnesses. Some of them even environmentally induced. There's more than one study out there that says the air quality in the average household is almost as toxic as some factories. Clearly, better housekeeping (not to mention a few open windows) are in order.
Housekeeping can be great inside of a structure and still result in occupants getting ill. Something like asbestos or other bad construction issues can result in environmentally induced illnesses, regardless of how dirty or clean a place is inside. Poor housekeeping might increases chances of such illness, but they are not a sole cause