In San Diego there have been no new cases of swine flu aside from the four cases already confirmed, but local health officials are still on alert.
The federal government declared a national public health emergency Sunday, although there have only been about 20 confirmed cases of swine flu in the United States so far, including four in San Diego County and three in Imperial County, and those cases were reportedly mild.
But that's not the case in Mexico, where more than a thousand people have caught the disease and at least 81 have died from it.
Swine flu is usually transmitted to humans by pigs, but public health officials are concerned about a possible pandemic because the new strain appears to be spreading from human to human.
However, in announcing the nationwide health emergency at a White House news briefing, Homeland Security Secretary Janet Napolitano added, "That sounds more severe than really it is," she said. "This is standard operating procedure and allows us to free up federal, state, and local agencies and their resources for prevention and mitigation."
Tamiflu and Relenza are believed to have been effective in fighting the disease, and the federal government is releasing about a quarter of its stock of the medicines to the states.
At a news conference Sunday in San Diego, state Superintendent of Schools Jack O'Connell said parents should not be concerned about sending their children to school.
"Our schools in California are safe," O'Connell said. "We want to make sure our parents and professional educators do everything they can to keep our schools safe."
He said local school administrators can download a free "Keep Our Schools Healthy" toolkit that includes sample letters to send home to parents and posters to place on campuses to remind children about proper hygiene. The toolkits come in multiple languages, O'Connell said.
To keep the outbreak in perspective, only a few children out of a state enrollment of 6.3 million students have been infected, he said.
All four people in San Diego County who came down with mild cases of the disease -- two boys ages 7 and 10 and a 54-year-old man and his 16-year-old daughter -- have recovered, said Dr. Wilma Wooten, the county's public health officer.
"There are no new cases that we're reporting for San Diego," Wooten said.
However, Imperial County reported a third case -- a 35-year-old woman hospitalized because of respiratory problems stemming from a pre-existing health condition.
The cases were mild and the symptoms were the same as with the "seasonal flu," Wooten said.
"It's certainly possible that individuals throughout the county have already been infected with the swine influenza virus and didn't realize it and didn't get tested," Wooten said.
People should handle the swine flu like any other flu infection -- stay home and only seek treatment if necessary, she said.
Wooten said two San Diegans died in the recent flu season, but not from swine flu.
An estimated 36,000 people in the United States die annually from the seasonal flu, she said.
Testing is the only way to differentiate between the swine flu and other flu strains, she said.
Wooten said 20 cases of swine flu have been confirmed in the United States, including infections in New York, Ohio, Texas and Kansas as well as California.
Medical officials recommend frequent washing of hands for at least 20 seconds with soap and water, covering your mouth and nose when coughing or sneezing, and remaining home when you get sick.
The Centers for Disease Control has issued an outbreak notice for Mexico, but has not issued any travel restrictions.
In Mexico City, people have taken to wearing surgical masks, and the government has closed schools and canceled public events, including church services, in an effort to slow the spread of the disease.
