NEW YORK — At least two cases of the human swine influenza have been confirmed in Kansas and one more in California, bringing the U.S. total to 11. At least eight students at a New York City high school probably have swine flu, but health officials said Saturday they don't know whether they have the same strain of the virus that has killed scores of people in Mexico.
A strain of the flu has killed as many as 68 people and sickened more than 1,000 across Mexico. The World Health Organization chief said Saturday the strain has "pandemic potential" and it may be too late to contain a sudden outbreak.
Kansas health officials said Saturday they had confirmed swine flu in a married couple living in the central part of the state after the husband visited Mexico. The couple, who live in Dickinson County, were not hospitalized, and the state described their illnesses as mild.
Dr. Jason Eberhart-Phillips, the state health officer, said, "Fortunately, the man and woman understand the gravity of the situation and are very willing to isolate themselves."
The man traveled to Mexico last week for a professional conference and became ill after he returned home. His wife became ill later. Their doctor suspected swine flu, but it was not confirmed until flu specimens were flown to the federal Centers for Disease Control and Prevention in Atlanta.
Swine flu is a respiratory disease of pigs caused by type A flu viruses, the CDC's Web site says. Human cases of swine flu are uncommon but can happen in people who are around pigs and can be spread from person to person. Symptoms of the flu include a fever of more than 100 degrees, body aches, coughing, a sore throat, respiratory congestion and, in some cases, vomiting and diarrhea.
At least nine swine flu cases have been reported in California and Texas. The new California case, the seventh there, was a 35-year-old Imperial County woman who was hospitalized but recovered. The woman, whose illness began in early April, had no known contact with the other cases.
Health officials are worried because people appear to have no immunity to the virus, a combination of bird, swine and human influenzas. Also, the virus presents itself like other swine flus, but none of the U.S. cases appear to involve direct contact with pigs, said Eberhart-Phillips, who called the strain "a completely novel virus."
"It appears to be able to transmit easily between humans," Eberhart-Phillips said. "It's something that could potentially become very big, and we're only seeing, potentially, the very beginning of a widespread outbreak."
New York health officials said more than 100 students at the private St. Francis Preparatory School, in Queens, had come down with a fever, sore throat and other aches and pains in the past few days. Some of their relatives also have been ill.
New York City Health Commissioner Thomas Frieden said nose and throat swabs had confirmed that eight students had a non-human strain of influenza type A, indicating probable cases of swine flu, but the exact subtypes were still unknown.
Samples had been sent to the CDC for more testing. Results were expected Sunday.
The symptoms in the New York cases have all been mild, and no students have been hospitalized, Frieden said, but the illnesses have caused concern because of the deadly outbreak in Mexico.
Frieden said that if the CDC confirms that the students have swine flu, he will likely recommend that St. Francis Preparatory remain closed on Monday "out of an abundance of caution."
"You could say, 'All you've got is a lot of kids with mild illness. Why close a school?'" Frieden said.
One factor, he said, is that the illness appears to be moving efficiently from person to person, affecting as many as 100 to 200 people in a student body of 2,700.
"We're very concerned about what may happen," he said, although he noted that the pattern of illness appeared different from Mexico, where much larger groups of people have become much sicker. Overall, flu cases have been declining in the city in recent weeks, he said.
"If we were to see, as they have in Mexico City, a large number of people becoming seriously ill with flu, that would be a very different situation from what we have now," he said.
The city health department has asked doctors to be extra vigilant in the coming days and test any patients who have flu-like symptoms and have traveled recently to California, Texas or Mexico.
Investigators also were testing children who fell ill at a day care center in the Bronx, Frieden said. And two families in Manhattan had contacted the city, saying they had recently returned ill from Mexico with flu-like symptoms.
Frieden said New Yorkers having trouble breathing due to an undiagnosed respiratory illness should seek treatment but shouldn't become overly alarmed. Medical facilities in the part of Queens near St. Francis Prep, he said, had already been flooded with people overreacting to the outbreak.