Two days off work

I have had the past two days off work due to the flu. I probably could have went today, but I still can't seem to eat. It hit my whole family hard. Where on earth does the illness come from?? I was talking to my fiance about this last night. We have three kids. One goes to daycare, one to headstart, the other in first grade....three kids, three different environments which are potential for viruses. Then there is myself and Michael..we both work...at two different places around people. There are more factors. Then if you figure in how my children's father had them last weekend, they were in another environment. There father works around lots of people. My sister works in fast food around people as does her fiance...there is another 3 possible locations. So if you add up how many people they are around, and the people they are around are around, it could be a damn epidemic!