Health officials across the Bay Area say they are actively monitoring the spread of swine flu in the U.S., though no cases have been reported locally.
Dr. Richard Besser, acting director of the U.S. Centers for Disease Control and Prevention, said today that his agency has confirmed 40 cases of the respiratory disease in five U.S. states including California, none of the cases producing serious illness.
There have been seven reported cases in California, four in San Diego County and three in Imperial County.
Health officials in Sacramento County confirmed a case of swine flu after a student reported feeling sick following a family trip to Cancun, Mexico. The boy is the eighth confirmed case of the illness in the state.
The small Catholic school in Fair Oaks has shut its doors through at least Wednesday.
The number of confirmed cases rose from 20 reported Sunday after further testing revealed the additional cases in New York City.
The CDC was also able to confirm several cases in Mexico.
Besser said that later today, "out of an abundance of caution," the CDC will issue a travel advisory recommending avoiding nonessential travel to Mexico.
He said "much is unknown" about how or where this strain of swine flu originated and that the agency was aggressively investigating the situation, in collaboration with international, state and local health officials.
According to the CDC, swine flu cases have been confirmed in New York, California, Texas, Ohio and Kansas. Only one person has been hospitalized and all of those infected have since recovered.
Influenza, including swine flu, is spread mainly from person to person through coughing or sneezing, and health officials recommend frequent hand washing and covering one's mouth when coughing or sneezing.
The seventh-grader at St. Mel felt sick last Monday and went home. Another classmate missed school on Wednesday with flu-like symptoms, and by Friday seven students were out, school officials said.