My son is in daycare and seems to pick up everything that anyone gets -- colds, flu, ear infections -- you name it. And then he brings it home! I've heard you say that a daycare of 6 or fewer would help, but switching to a smaller daycare is just not practical. What else can I do to prevent the cycle from continuing to infect us all? I don't want my son to be sick and I can't miss any more work!

As an active pediatrician, I am exposed to every cold and flu virus in every daycare center in our community. Think about it! Sneezed on, slobbered on – I even wind up examining poopy diapers that parents bring in for my educated opinion. I have a front row seat to contagious diseases.

I am often asked how I manage to avoid so many of the colds, flus, and diarrheal illnesses that sweep through town. Part of the answer is that, over the years, my immune system has met many of these microscopic invaders, learned about them, and now stands ready with antibodies to prevent infection. This has happened over time, often with no conscious help from me. Appropriate vaccines do this same job in a number of instances (I get the flu vaccine each year, for instance).

When possible, I try to help keep my immune system functioning in peak form. Getting good nutrition (plenty of fresh fruits, vegetables, whole grains, and supplements for the areas in which my diet is not adequate) is a foundation for good health. Plenty of good sleep is vital (perhaps the toughest one for me). Plenty of activity (a brisk walk by the waterfront is my favorite), and lots of love and laughter both strengthen the immune system (read the compelling Anatomy of an Illness by Greene family friend Norman Cousins if you've missed this classic). Avoiding inordinate stress helps too – and this is something I've still got a lot to learn about.

Whatever shape your immune system is in, it makes sense to minimize the overwhelming numbers of disease-causing germs you are exposed to. There are four key ways to do this:

Decrease the disease-causing germs on surfaces in the home.

Where are these germs truly a problem? Where does this really make a difference? In a number of different fascinating studies, researchers have carefully cultured every imaginable surface of typical homes to find where the disease-causing germs live. It turns out that the kitchen harbors more germs than any other room in the home -- yes, more than the bathroom. The greatest concentration is found in the moist germ havens we call kitchen sponges and dishcloths. These are the very same germs with which people in that household get sick. Sink drains, faucet handles, and doorknobs -- either in the kitchen or bathroom -- are the next highest on the list. Toilet seats had fewer germs than any other surface tested (Journal of Applied Microbiology, 1998;85(5):19--28)! If we can keep these objects clean -- especially the sponges and dishcloths -- we can cut the spread of infection.

But here's the problem:

Tossing a dishcloth in the washing machine, even with a strong detergent, doesn't appreciably cut down on surviving germs. The micro-crevices that make a sponge such an effective cleaning device make it even more difficult to disinfect. Running a sponge through the dishwasher makes it look clean but leaves it just as infectious.