Mr. Clean

As the state's chief epidemiologist, DeMaria has become an evangelist for remarkably simple methods of basic hygiene, asserting that one of the best ways to avoid diseases such as swine flu is to follow some fundamental rules we all learned - or should have learned - from our mothers.

The most obvious and sometimes the most overlooked is hand-washing, he said. A quick run-the-water-over-your-hands-for-a-second will not do. He advocates a thorough scrubbing with warm water and lots of soap, for at least 20 seconds.

"It's really that foaming, lathering action and the rinse that gets the virus or the bacteria off your hands," said DeMaria, taking a break yesterday from monitoring the swine flu outbreak to demonstrate proper techniques in a bathroom at state Department of Public Health headquarters.

"Sometimes you want to take off the ring," he said of jewelry as he vigorously rubbed his bubble-covered hands together.

The hand-washing gospel is one health specialists have pushed for years, as repeated studies have shown that many Americans do not wash after using public restrooms. Men, the studies have shown, are typically more negligent than women.

But proper hygiene has taken on an elevated importance in the two weeks since the swine flu outbreak began. The virus has spread to more than 400 people nationwide, including several dozen so far in Massachusetts.

"Everything we know about transmission of infection suggests that the hands play a big role in many of those infections," DeMaria said.

OK, but what if you're not near a sink? You get off the T, you stop for a bagel on the way to work, then what?

Yes, DeMaria said, those ubiquitous alcohol-based hand sanitizers are very effective. Particularly for the influenza virus, he said, "alcohol really destroys its infectiousness."

"You don't want to put too little; you don't want to put too much," he said, filling the palm of his hand with two squirts. "Make sure that your hands are uniformly wet."

DeMaria has been carrying a small bottle of the cleanser in his pocket for years. He said it makes it less horrifying to watch people cough into their hands and then touch something he has to touch.

So what if you are the one coughing or sneezing? Do not cover your mouth with your hand, DeMaria said; the safest thing is to use is a tissue. Absent that, use the crook of your elbow, he said, burying his face in his tweed blazer to demonstrate.

"People say, 'Well, you know, this is kind of trivial,' " DeMaria said of his hygiene tips. "The fact is, if you do these things, you can reduce transmission in your own family and your own community. And when you have something like swine flu, where we really don't know where it's going to go or what it is exactly, it's so important that everybody do that now."

Take heart, he practices what he preaches: Even before yesterday's interview, the reporter came upon DeMaria dutifully washing up in the men's room. He ran the faucet for a long time. Maybe even 20 seconds.

Scott Helman can be reached at shelman@globe.com.