Wash your hands. Cover your mouth when you cough or sneeze. Keep your hands away from your eyes, mouth and nose.

The same things your mother told you as a child are still critical today as the nation experiences what is expected to be its worst flu season in a decade.

And it’s early, too. The flu season just got under way two months ago and can run as late as April or early May.

That’s precisely what has health experts on edge — that and the fact that the traditional flu season is being supplemented by the arrival of a new kind of intestinal bug and the worst outbreak of whooping cough in more than 50 years.

Overall, based on the week ending Dec. 29, all but seven states and the District of Columbia were experiencing a “widespread” outbreak of the flu, according to the U.S. Centers for Disease Control and Prevention.

How bad is it?

Boston Mayor Thomas Menino declared a public health emergency in response to 700 confirmed cases of the flu — 10 times more than all of last year. Across Massachusetts, 18 deaths have been attributed to the flu.

Lehigh Valley Hospital-Cedar Crest in Allentown, Pa., has erected a heated tent outside the hospital to treat patients with mild symptoms and keep them isolated from the more serious cases inside. So far, 22 flu-related deaths have been recorded statewide.

In New Hampshire, 13 deaths were attributed to the flu in December, considerably more than in recent years.

While none of the deaths has involved children, Dr. Jose Montero, the state’s public health director, warned the virus can spread easily among schools and day care centers.

So, get vaccinated. Avoid close contact with people who are sick. Cover your mouth when you cough or sneeze. Avoid touching your eyes, mouth and nose. And wash your hands.

— The Nashua (N.H.) Telegraph