State health officials had expected to get verification Monday that a crew member aboard a cruise ship in Alaska waters contracted swine flu, but officials may have to wait a bit longer.
Ann Potempa, a spokeswoman for the state Department of Health and Social Services, said it looks increasingly unlikely the verification would come Monday.
The testing was done at the Washington State Public Health Laboratory and was being verified by the Centers for Disease Control and Prevention in Atlanta.
Dr. Jay Butler, Alaska's chief medical officer, announced Sunday that the crew member aboard the Serenade of the Seas had a probable case of swine flu but testing was being conducted by the federal health agency for confirmation. No other people aboard the ship reported flu-like symptoms since the woman became ill on May 2. She was placed in isolation two days later.
The female crew member underwent a course of treatment with Tamiflu, an anti-viral medication that is effective against swine flu. She has not had flu symptoms or been running a fever for several days.
Cynthia Martinez, spokeswoman for Royal Caribbean International, said the female crew member completed a CDC-recommended 7-day period of isolation, but she did not know if the crew member had been cleared to rejoin the crew. She said the woman will have to meet with the ship's doctor and be cleared to go back to work.
The Serenade of the Seas is on a 14-day cruise to southeast Alaska and Canada. Its next port-of-call is in Sitka on Tuesday. It departed San Francisco and headed north on May 2, the same day the female crew member began feeling sick.
Butler has said there is no reason to restrict the movement of passengers aboard the ship, as long as they are not reporting flu-like symptoms.
Before embarking on the Alaska cruise, the Serenade of the Seas departed San Juan, Puerto Rico for a 14-night Panama Canal voyage in which the ship visited Mexico, the country hit hardest by swine flu. Scientists now say that the new strain of swine flu could have sickened 23,000 people in Mexico before anyone realized it was an epidemic on April 23.
Butler said the ship's medical staff followed strict isolation procedures to prevent the spread of the illness.
At least 61 people have been killed by swine flu around the world, and the World Health Organization has confirmed 4,800 cases.
Butler said the case aboard the ship can't be considered Alaska's first case for several reasons, including that the testing was done outside Alaska and the crew member is not an Alaskan.
After swine flu cases, Deer Park schools reopen
When Kathleen Donlon returned to school in Deer Park Monday after it had been shut down because several students were sickened with swine flu, the fourth-grader did as her mother asked: She washed her hands throughout the day.
"About four times," Kathleen, 10, said in an interview in the John F. Kennedy Intermediate School parking lot Monday when her mother, Peggy Donlon, 44, picked her up.
The school is cleaner and notices that once hung on bulletin boards throughout the building were gone, Kathleen said, but other than that everything seemed normal again.
At first, she said, she was a tad apprehensive about going back to class.
"A little bit because I didn't want to catch it," Kathleen said.
JFK and Deer Park's five other public schools, which serve 4,400 students, total, were closed all last week as a precaution after it was learned that three female students contracted the swine flu, also known as H1N1 virus. A fourth student was confirmed to have the virus on Thursday.
All four students have recovered and are back at school, said Elizabeth Marino, superintendent of the Deer Park school district.
Monday, Humayun J. Chaudhry, commissioner of Suffolk County's Department of Health Services, said there have been no additional cases of H1N1 flu reported in Suffolk since Thursday.
With the school closings, Marino said the district took the opportunity to scrub and clean its six buildings and school buses.
Monday at JFK, only 37 students out of 987 were absent, she said. That's a stark contrast to April 30, when 321 students did not come to class at JFK.
Yvonne Mirabito sent her daughter, a third-grader, back to class Monday with a bottle of hand sanitizer and instructed her not to drink from the school's water fountains.
"As a precaution I gave her the hand sanitizer, even though I do feel very confident that they cleaned the school from top to bottom," said Mirabito.
Linda Ponterio, of Deer Park, reminded her daughter, Kristin, a fifth-grader, about personal hygiene. She asked her daughter to cover her mouth when she sneezes and not eat her friends' foods or offer foods to her friends unless they were individually wrapped.
"I just reinforced them a bit more," Ponterio said.
All three women said they supported the district's decision to shut the schools down for a week.
"About four times," Kathleen, 10, said in an interview in the John F. Kennedy Intermediate School parking lot Monday when her mother, Peggy Donlon, 44, picked her up.
The school is cleaner and notices that once hung on bulletin boards throughout the building were gone, Kathleen said, but other than that everything seemed normal again.
At first, she said, she was a tad apprehensive about going back to class.
"A little bit because I didn't want to catch it," Kathleen said.
JFK and Deer Park's five other public schools, which serve 4,400 students, total, were closed all last week as a precaution after it was learned that three female students contracted the swine flu, also known as H1N1 virus. A fourth student was confirmed to have the virus on Thursday.
All four students have recovered and are back at school, said Elizabeth Marino, superintendent of the Deer Park school district.
Monday, Humayun J. Chaudhry, commissioner of Suffolk County's Department of Health Services, said there have been no additional cases of H1N1 flu reported in Suffolk since Thursday.
With the school closings, Marino said the district took the opportunity to scrub and clean its six buildings and school buses.
Monday at JFK, only 37 students out of 987 were absent, she said. That's a stark contrast to April 30, when 321 students did not come to class at JFK.
Yvonne Mirabito sent her daughter, a third-grader, back to class Monday with a bottle of hand sanitizer and instructed her not to drink from the school's water fountains.
"As a precaution I gave her the hand sanitizer, even though I do feel very confident that they cleaned the school from top to bottom," said Mirabito.
Linda Ponterio, of Deer Park, reminded her daughter, Kristin, a fifth-grader, about personal hygiene. She asked her daughter to cover her mouth when she sneezes and not eat her friends' foods or offer foods to her friends unless they were individually wrapped.
"I just reinforced them a bit more," Ponterio said.
All three women said they supported the district's decision to shut the schools down for a week.
Swine flu: is it safe to travel?
What every traveller wants to know is: am I increasing my risk of exposure to swine flu by travelling abroad or should I play it safe and stay at home?
As the alert level for a pandemic rises, one control measure has been strikingly absent – neither national governments nor the World Health Organisation (WHO) have attempted to bring international travel – even to Mexico – to a halt.
The reason is that such a ban would make almost no practical difference. For example, a 90 per cent ban on global travel, introduced at the earliest sign of trouble, would have delayed the arrival of people infected with swine flu into Britain by a week and a half. A 99 per cent ban – difficult to impose – would have delayed the arrival of such people by just three weeks.
Does that tell us that travel is safe? No, but the current risk of contracting flu from travel is still small. Leaving aside Mexico, is it safe to visit other countries with reported cases? How can we compare the risk of visiting a country with good surveillance systems in place, which has revealed and confirmed a number of imported cases, with the risk of travelling to a country with no reports of any problems but, perhaps, no reporting systems either? Is it safer to stay at home?
The greatest risks may come from the journey itself: a coughing cab driver, crowded airports, a febrile passenger in the next seat… The experience of Sars in 2003, and our subsequent efforts to understand and prepare for H5N1 bird flu, will be invaluable, but until we know much more about the new viral strain – how quickly and easily it spreads, and whether the illness is really as mild as we now believe – these will be the hardest risks to understand.
Prepare for a new etiquette – socially, in the workplace, and certainly in the aircraft cabin. "Social distancing" and self-isolation will be the new order of the day, and anyone with flu symptoms should opt to stay at home. We shall have to take much more care with hand washing, hygiene, blowing noses in public, shaking hands, and kissing our acquaintances and friends on the cheek. More people will be using face masks.
For those of a nervous disposition it won't be much fun to travel in this climate of anxiety, suspicion and alarm. But at least choosing whether to travel is still a matter for the individual. I'm heading for a conference in Istanbul next week and will not be changing my travel plans.
As the alert level for a pandemic rises, one control measure has been strikingly absent – neither national governments nor the World Health Organisation (WHO) have attempted to bring international travel – even to Mexico – to a halt.
The reason is that such a ban would make almost no practical difference. For example, a 90 per cent ban on global travel, introduced at the earliest sign of trouble, would have delayed the arrival of people infected with swine flu into Britain by a week and a half. A 99 per cent ban – difficult to impose – would have delayed the arrival of such people by just three weeks.
Does that tell us that travel is safe? No, but the current risk of contracting flu from travel is still small. Leaving aside Mexico, is it safe to visit other countries with reported cases? How can we compare the risk of visiting a country with good surveillance systems in place, which has revealed and confirmed a number of imported cases, with the risk of travelling to a country with no reports of any problems but, perhaps, no reporting systems either? Is it safer to stay at home?
The greatest risks may come from the journey itself: a coughing cab driver, crowded airports, a febrile passenger in the next seat… The experience of Sars in 2003, and our subsequent efforts to understand and prepare for H5N1 bird flu, will be invaluable, but until we know much more about the new viral strain – how quickly and easily it spreads, and whether the illness is really as mild as we now believe – these will be the hardest risks to understand.
Prepare for a new etiquette – socially, in the workplace, and certainly in the aircraft cabin. "Social distancing" and self-isolation will be the new order of the day, and anyone with flu symptoms should opt to stay at home. We shall have to take much more care with hand washing, hygiene, blowing noses in public, shaking hands, and kissing our acquaintances and friends on the cheek. More people will be using face masks.
For those of a nervous disposition it won't be much fun to travel in this climate of anxiety, suspicion and alarm. But at least choosing whether to travel is still a matter for the individual. I'm heading for a conference in Istanbul next week and will not be changing my travel plans.
With swine flu, we're all in this together
On the western edge of Mexico's capital, 10 new luxury apartment towers promise an antiseptically modern lifestyle with spas, private playgrounds and an exclusive shopping center. Blocks away, a world-class private hospital has opened.
But there's no escaping the view from these $1.5 million apartments: Just across a ravine is a slum where maids and construction workers make do in crowded, humid homes of raw concrete and spotty drinking water. For them, getting sick means medicating themselves at a discount pharmacy, or waiting for hours in an overcrowded public hospital.
Wealthy Mexicans aren't alone in trying — and failing — to distance themselves from deprivation and disease. People all over the world want to protect their families from the problems of the less fortunate.
But if there's anything we've learned from the swine flu epidemic, it is this: the virus doesn't discriminate.
"We're all in this together," President Barack Obama said as he urged public health agencies to reach all corners of America. "When one person gets sick, it has the potential of making us all sick."
The outbreak might not have become an epidemic if Mexico's first swine flu victims had been identified and treated quickly. We now know that for most, the virus causes only mild symptoms, and that nearly all of those who become quite sick can recover if they get proper treatment within 48 hours.
We also know that most of Mexico's dead didn't get that treatment in time.
But it feels awfully late to be pointing fingers over initial delays. And by ordering a nationwide shutdown last week of public gathering places where flu can spread, Mexico saved many more lives, experts say.
Now the world must face what Mexicans learned as they stayed home from schools and restaurants, venturing outside fearfully in face masks only to replenish their refrigerators: Rich and poor breathe the same air. The 53 people killed around the world so far range from poor day laborers to the grandson of one of the richest men in Mexico.
It's a moral challenge, as clear now as the view from those luxury living room windows: When vast numbers of poor people lack decent health care, no one is immune from disease.
A rural bricklayer with a bad cough, a kindergartner in a remote mountain village, a maintenance worker in a vast urban slum — these swine flu cases might have seemed a world away from the United States and Europe.
But it takes just four hours by bus for workers to reach the capital from the pig-farming community of La Gloria, where hundreds of villagers were suffering from acute respiratory infections for weeks before one of their kindergartners became Mexico's earliest confirmed swine flu case.
It takes even less time to fly from Mexico City to the U.S., where this strange new strain of swine flu was first identified in a 10-year-old San Diego boy.
No one knows yet where this outbreak began. Despite calls to close the U.S. border, scientists say the deadly chimera — a blend of bird, human and pig flu genes for which humans have limited natural immunity — may have jumped from pigs to humans in North Carolina, about 10 years and 10,000 generations of virus ago.
Millions of dollars have been spent on pandemic preparedness since scientists realized flu could jump between species. Top flu experts even developed a detailed containment plan — with an extremely limited window of opportunity.
World Health Organization experts determined that a virus with pandemic potential would have to be identified, the epicenter quarantined and 80 percent of the initially affected population blanketed with antiviral drugs within three weeks of the first symptoms.
Oh, and the outbreak would have to be limited to a small geographic area — like a remote village of about 1,000 people.
This H1N1 virus was likely spreading all over Mexico and parts of the United States long before anyone got sick enough to be tested. By the time the wheezing, sneezing villagers of La Gloria complained enough for their samples to be taken, dozens had been commuting to Mexico City for weeks.
Before anyone knew this flu's name, cases were popping up all over the megalopolis of 20 million.
A Canadian lab quickly confirmed that swine flu had reached Mexico, and a global alarm was raised. But only hours later, the WHO said it was useless to close borders and ban flights. Travelers had already carried the virus from Mexico to New York and New Zealand. It has since spread to at least 29 countries around the world.
So now Mexico's challenge has become a truly global problem. Experts say even normal seasonal flu infects millions and kills about 500,000 people worldwide every year. With the WHO warning that a possible swine flu pandemic could infect 2 billion people, how on earth can we protect the whole world?
The drug makers say they can "most likely" produce 917 million doses in 10 months, a number considered overly ambitious by some experts.
Even the first vaccines won't be ready for months — too late for the Southern Hemisphere, where flu season is about to start. And if the virus evolves into something more contagious or deadly — possibly by mixing with regular flu or even H5N1 bird flu, which is endemic in parts of Asia and Africa — these vaccines may not provide much protection in the end.
Antiviral drugs will be critical if it comes to that, but they are expensive, and there aren't enough to go around. The largest stockpiles are kept by the wealthiest nations, for their own citizens' protection.
But hoarding antivirals could backfire. A 2007 study modeled what would happen in a flu pandemic if wealthy nations hoard or share these drugs.
They concluded that the hardest-hit populations should be blanketed with antivirals, even if they are too poor to pay for them, and even if it means people with reliable health care in wealthier nations would go untreated.
Doing so would save many millions of lives, they found — including in the wealthy countries that share.
Nobody knows where this current outbreak is headed as the swine flu virus evolves. It may lose its potency.
But there's no escaping the view from these $1.5 million apartments: Just across a ravine is a slum where maids and construction workers make do in crowded, humid homes of raw concrete and spotty drinking water. For them, getting sick means medicating themselves at a discount pharmacy, or waiting for hours in an overcrowded public hospital.
Wealthy Mexicans aren't alone in trying — and failing — to distance themselves from deprivation and disease. People all over the world want to protect their families from the problems of the less fortunate.
But if there's anything we've learned from the swine flu epidemic, it is this: the virus doesn't discriminate.
"We're all in this together," President Barack Obama said as he urged public health agencies to reach all corners of America. "When one person gets sick, it has the potential of making us all sick."
The outbreak might not have become an epidemic if Mexico's first swine flu victims had been identified and treated quickly. We now know that for most, the virus causes only mild symptoms, and that nearly all of those who become quite sick can recover if they get proper treatment within 48 hours.
We also know that most of Mexico's dead didn't get that treatment in time.
But it feels awfully late to be pointing fingers over initial delays. And by ordering a nationwide shutdown last week of public gathering places where flu can spread, Mexico saved many more lives, experts say.
Now the world must face what Mexicans learned as they stayed home from schools and restaurants, venturing outside fearfully in face masks only to replenish their refrigerators: Rich and poor breathe the same air. The 53 people killed around the world so far range from poor day laborers to the grandson of one of the richest men in Mexico.
It's a moral challenge, as clear now as the view from those luxury living room windows: When vast numbers of poor people lack decent health care, no one is immune from disease.
A rural bricklayer with a bad cough, a kindergartner in a remote mountain village, a maintenance worker in a vast urban slum — these swine flu cases might have seemed a world away from the United States and Europe.
But it takes just four hours by bus for workers to reach the capital from the pig-farming community of La Gloria, where hundreds of villagers were suffering from acute respiratory infections for weeks before one of their kindergartners became Mexico's earliest confirmed swine flu case.
It takes even less time to fly from Mexico City to the U.S., where this strange new strain of swine flu was first identified in a 10-year-old San Diego boy.
No one knows yet where this outbreak began. Despite calls to close the U.S. border, scientists say the deadly chimera — a blend of bird, human and pig flu genes for which humans have limited natural immunity — may have jumped from pigs to humans in North Carolina, about 10 years and 10,000 generations of virus ago.
Millions of dollars have been spent on pandemic preparedness since scientists realized flu could jump between species. Top flu experts even developed a detailed containment plan — with an extremely limited window of opportunity.
World Health Organization experts determined that a virus with pandemic potential would have to be identified, the epicenter quarantined and 80 percent of the initially affected population blanketed with antiviral drugs within three weeks of the first symptoms.
Oh, and the outbreak would have to be limited to a small geographic area — like a remote village of about 1,000 people.
This H1N1 virus was likely spreading all over Mexico and parts of the United States long before anyone got sick enough to be tested. By the time the wheezing, sneezing villagers of La Gloria complained enough for their samples to be taken, dozens had been commuting to Mexico City for weeks.
Before anyone knew this flu's name, cases were popping up all over the megalopolis of 20 million.
A Canadian lab quickly confirmed that swine flu had reached Mexico, and a global alarm was raised. But only hours later, the WHO said it was useless to close borders and ban flights. Travelers had already carried the virus from Mexico to New York and New Zealand. It has since spread to at least 29 countries around the world.
So now Mexico's challenge has become a truly global problem. Experts say even normal seasonal flu infects millions and kills about 500,000 people worldwide every year. With the WHO warning that a possible swine flu pandemic could infect 2 billion people, how on earth can we protect the whole world?
The drug makers say they can "most likely" produce 917 million doses in 10 months, a number considered overly ambitious by some experts.
Even the first vaccines won't be ready for months — too late for the Southern Hemisphere, where flu season is about to start. And if the virus evolves into something more contagious or deadly — possibly by mixing with regular flu or even H5N1 bird flu, which is endemic in parts of Asia and Africa — these vaccines may not provide much protection in the end.
Antiviral drugs will be critical if it comes to that, but they are expensive, and there aren't enough to go around. The largest stockpiles are kept by the wealthiest nations, for their own citizens' protection.
But hoarding antivirals could backfire. A 2007 study modeled what would happen in a flu pandemic if wealthy nations hoard or share these drugs.
They concluded that the hardest-hit populations should be blanketed with antivirals, even if they are too poor to pay for them, and even if it means people with reliable health care in wealthier nations would go untreated.
Doing so would save many millions of lives, they found — including in the wealthy countries that share.
Nobody knows where this current outbreak is headed as the swine flu virus evolves. It may lose its potency.
Swine flu threat fades - for now
Almost as quickly as it appeared, swine flu has faded as a public health threat - for now. But that could change by winter.
Public health experts say the virus has a chance of returning in a new and more dangerous form when the influenza season picks up again in late November, and are deciding now how to protect people worldwide.
They are preparing even as an increasing number of infectious disease experts are saying that the swine flu does not show signs of reappearing in a more virulent form next winter. It could even disappear altogether or more likely, come back and join the other strains of usually mild flu that typically circulate among humans each winter, they say.
But no one knows for sure.
"I wish I could predict what we are going to see, because it would be very easy to make the kinds of decisions we need to make as a nation over the next few months," said Dr. Richard Besser, acting director of the Center for Disease Control and Prevention, in a news conference late last week.
The CDC has started growing the virus in labs as a first step toward making a swine flu vaccine, and World Health Organization leaders will meet Wednesday to discuss when - and how - global manufacturing of a vaccine should start.
At the same time, infectious disease experts will spend the next few months studying the swine flu - a strain of influenza A, subtype H1N1 - to figure out just how dangerous it is, or could become. And public health experts will prepare for ways to keep the swine flu contained if there is another outbreak, including devising plans to close schools again when necessary.
Even if swine flu turns out to be no more virulent than seasonal flu, that's nothing to dismiss - seasonal flu kills about 36,000 people every year.
The flu is a respiratory illness caused by the influenza virus. Typically three strains of flu infect people every winter - two types of influenza A and one type of influenza B.
One of the distinguishing traits of influenza is its ability to mutate quickly and easily. The virus is made up of eight segments that will shift as the disease replicates. That leads to frequent small mutations, and when two different strains of influenza are in one person, or animal, the strains can mix and create significant mutations.
"That's why we have to vaccinate every year," said David Lewis, an infectious disease specialist with Stanford University School of Medicine. "There are always changes."
"Every time influenza replicates itself, it has a tendency to naturally make some mistakes," he said. "That means it's generating a whole bunch of slight changes that can be selected for a slight advantage. So it's a very rapid natural selection for whatever virus is able to elude the immune system."
That's what scientists believe happened with swine flu, which is a mix of viruses found in pigs, birds and humans. What alarmed infectious disease experts was the virus' ability to pass from person to person - a trait that could prove devastating if a virus is particularly harmful to humans.
So far the symptoms of swine flu appear to be mild, especially in the cases found in the United States. More than 1,600 confirmed cases of swine flu were reported in the United States over the past three weeks, about 50 people were hospitalized and two died. On Saturday, health officials in Washington state reported a death that also may have been caused by swine flu.
In the early days of the outbreak in Mexico, it seemed to be a serious health threat because it killed more than 150 people. But epidemiologists believe many thousands of mild cases of swine flu in Mexico were never reported - making it no more deadly than seasonal flu.
Why experts worry
But this particular strain is new to humans - leaving people with little natural immunity to it - which would mean more people would be vulnerable to infection. Given that vulnerability, a more virulent form in the winter would be all that much more worrisome.
So public health experts are preparing. The most famous influenza epidemic in recent history started in the spring of 1917 with a mild outbreak of the flu that returned months later and killed millions worldwide.
"I don't think this (swine flu) is going to be a pandemic. I worry about a true pandemic with a wholly new strain (of influenza) more than I worry about this one. But you can't ignore it," said Dr. Larry Drew, director of the UCSF virology lab. "We're going to have to address this strain."
The most important step, say infectious disease experts, will be preparing a vaccine. But public health officials have difficult decisions to make right now if they intend to have a vaccine ready by next winter.
They must decide whether the swine flu vaccine should be combined with the seasonal flu vaccine, which is already designed to combat three forms of influenza. Some vaccine experts worry that adding swine flu into the mix will dilute the protective abilities of the rest of the vaccine - and argue there probably won't be enough time to test the efficacy of combining all four.
If swine flu can't be combined in the usual vaccine, a separate one will have to be made. But that raises questions of how many vaccine doses to prepare worldwide, and whether developing a new vaccine will interrupt manufacturing of the seasonal vaccine.
Who gets vaccinated
Then there's the question of who would be best served by a vaccine. With swine flu getting so much attention, demand will almost definitely be higher than normal this year, say public health experts.
"Given the lead time, we probably have the ability to make a vaccine, at least for the United States. But part of it depends on how many people you're planning on vaccinating," Lewis said. "This next season there will probably be a real crush to get vaccines."
If there aren't enough vaccines to give to everyone who wants them, priority will go to the most vulnerable - young children and the elderly, along with people who have other health risks or who work in health care.
Since early evidence suggests that young people - particularly teenagers and young adults - make up most of the cases of swine flu, it may be logical to target a vaccine to high school and college students, said Drew. That's yet another piece of the swine flu mystery that researchers will be studying this summer.
Meanwhile, Besser of the CDC is urging local public health officials and communities to be prepared for the worst.
"What would they do if this came back and was really severe and we needed to take measures like closing schools?" he said. "That kind of preparedness over this period of time will really help minimize the impact, should this come back and be more severe."
Public health experts say the virus has a chance of returning in a new and more dangerous form when the influenza season picks up again in late November, and are deciding now how to protect people worldwide.
They are preparing even as an increasing number of infectious disease experts are saying that the swine flu does not show signs of reappearing in a more virulent form next winter. It could even disappear altogether or more likely, come back and join the other strains of usually mild flu that typically circulate among humans each winter, they say.
But no one knows for sure.
"I wish I could predict what we are going to see, because it would be very easy to make the kinds of decisions we need to make as a nation over the next few months," said Dr. Richard Besser, acting director of the Center for Disease Control and Prevention, in a news conference late last week.
The CDC has started growing the virus in labs as a first step toward making a swine flu vaccine, and World Health Organization leaders will meet Wednesday to discuss when - and how - global manufacturing of a vaccine should start.
At the same time, infectious disease experts will spend the next few months studying the swine flu - a strain of influenza A, subtype H1N1 - to figure out just how dangerous it is, or could become. And public health experts will prepare for ways to keep the swine flu contained if there is another outbreak, including devising plans to close schools again when necessary.
Even if swine flu turns out to be no more virulent than seasonal flu, that's nothing to dismiss - seasonal flu kills about 36,000 people every year.
The flu is a respiratory illness caused by the influenza virus. Typically three strains of flu infect people every winter - two types of influenza A and one type of influenza B.
One of the distinguishing traits of influenza is its ability to mutate quickly and easily. The virus is made up of eight segments that will shift as the disease replicates. That leads to frequent small mutations, and when two different strains of influenza are in one person, or animal, the strains can mix and create significant mutations.
"That's why we have to vaccinate every year," said David Lewis, an infectious disease specialist with Stanford University School of Medicine. "There are always changes."
"Every time influenza replicates itself, it has a tendency to naturally make some mistakes," he said. "That means it's generating a whole bunch of slight changes that can be selected for a slight advantage. So it's a very rapid natural selection for whatever virus is able to elude the immune system."
That's what scientists believe happened with swine flu, which is a mix of viruses found in pigs, birds and humans. What alarmed infectious disease experts was the virus' ability to pass from person to person - a trait that could prove devastating if a virus is particularly harmful to humans.
So far the symptoms of swine flu appear to be mild, especially in the cases found in the United States. More than 1,600 confirmed cases of swine flu were reported in the United States over the past three weeks, about 50 people were hospitalized and two died. On Saturday, health officials in Washington state reported a death that also may have been caused by swine flu.
In the early days of the outbreak in Mexico, it seemed to be a serious health threat because it killed more than 150 people. But epidemiologists believe many thousands of mild cases of swine flu in Mexico were never reported - making it no more deadly than seasonal flu.
Why experts worry
But this particular strain is new to humans - leaving people with little natural immunity to it - which would mean more people would be vulnerable to infection. Given that vulnerability, a more virulent form in the winter would be all that much more worrisome.
So public health experts are preparing. The most famous influenza epidemic in recent history started in the spring of 1917 with a mild outbreak of the flu that returned months later and killed millions worldwide.
"I don't think this (swine flu) is going to be a pandemic. I worry about a true pandemic with a wholly new strain (of influenza) more than I worry about this one. But you can't ignore it," said Dr. Larry Drew, director of the UCSF virology lab. "We're going to have to address this strain."
The most important step, say infectious disease experts, will be preparing a vaccine. But public health officials have difficult decisions to make right now if they intend to have a vaccine ready by next winter.
They must decide whether the swine flu vaccine should be combined with the seasonal flu vaccine, which is already designed to combat three forms of influenza. Some vaccine experts worry that adding swine flu into the mix will dilute the protective abilities of the rest of the vaccine - and argue there probably won't be enough time to test the efficacy of combining all four.
If swine flu can't be combined in the usual vaccine, a separate one will have to be made. But that raises questions of how many vaccine doses to prepare worldwide, and whether developing a new vaccine will interrupt manufacturing of the seasonal vaccine.
Who gets vaccinated
Then there's the question of who would be best served by a vaccine. With swine flu getting so much attention, demand will almost definitely be higher than normal this year, say public health experts.
"Given the lead time, we probably have the ability to make a vaccine, at least for the United States. But part of it depends on how many people you're planning on vaccinating," Lewis said. "This next season there will probably be a real crush to get vaccines."
If there aren't enough vaccines to give to everyone who wants them, priority will go to the most vulnerable - young children and the elderly, along with people who have other health risks or who work in health care.
Since early evidence suggests that young people - particularly teenagers and young adults - make up most of the cases of swine flu, it may be logical to target a vaccine to high school and college students, said Drew. That's yet another piece of the swine flu mystery that researchers will be studying this summer.
Meanwhile, Besser of the CDC is urging local public health officials and communities to be prepared for the worst.
"What would they do if this came back and was really severe and we needed to take measures like closing schools?" he said. "That kind of preparedness over this period of time will really help minimize the impact, should this come back and be more severe."
Students rethink plans for traveling in swine flu's wake
Carlos Beltran, a first-year-business student at Michigan State University, is worried about H1N1 flu -- but not in Michigan where the illnesses have been few and mild. The Mexico City native has been trying to keep up with friends and family in his nation's capital, which was hard-hit by the novel virus.
"No one was concerned at first," he said. Then the Mexican government shut schools and businesses and told people to stay at home. The metropolis of 20 million became a ghost town for a while, he said.
Since the first public reports of swine flu in Mexico surfaced in late April, 44 people with flu-like symptoms have died and at least 1,204 have fallen ill. An early spate of deaths fueled belief it was particularly deadly, and U.S. health officials prepared for a pandemic.
H1N1 hasn't been as deadly in the United States, but health officials say not to assume swine flu is over. Consequently, people in Michigan with ties to Mexico are reconsidering travel plans.
In spite of the distance between him and the worst of swine flu, Beltran is feeling its wrath. The business school is leaving for China on Tuesday, and the 28-year-old said he isn't going, for fear of being quarantined. China recently quarantined, then released, several people from Mexico.
In Monterrey, Mexico, Priscila Martinez said, her grandparents "don't take precautions like they should." The 19-year-old and her mother left Mexico for Canton when she was 11. Now at the University of Michigan, the junior political science major said she didn't know what flu was until she came to the United States.
"We don't get vaccines," she said. "We don't talk about it."
David Hayes-Bautista, an epidemiologist at the University of California, Los Angeles, who studies Latino health issues, said illnesses like flu are top-10 killers in Mexico. It's a perception problem, he said.
Former Mexican minister of health Julio Frenk said recently that about 10,000 people die of flu complications each year in Mexico, making its death rate slightly less than in the United States, where 36,000 of the 306 million Americans die each year.
Even with what has been learned since the outbreak began, Victoria Pardo , a 22-year-old math major from Dearborn at Wayne State University, still is rethinking her August trip to Chihuahua, a border state where the third-generation Mexican American has been a missionary.
"The thought of even being there worries me and my family," she said.
"No one was concerned at first," he said. Then the Mexican government shut schools and businesses and told people to stay at home. The metropolis of 20 million became a ghost town for a while, he said.
Since the first public reports of swine flu in Mexico surfaced in late April, 44 people with flu-like symptoms have died and at least 1,204 have fallen ill. An early spate of deaths fueled belief it was particularly deadly, and U.S. health officials prepared for a pandemic.
H1N1 hasn't been as deadly in the United States, but health officials say not to assume swine flu is over. Consequently, people in Michigan with ties to Mexico are reconsidering travel plans.
In spite of the distance between him and the worst of swine flu, Beltran is feeling its wrath. The business school is leaving for China on Tuesday, and the 28-year-old said he isn't going, for fear of being quarantined. China recently quarantined, then released, several people from Mexico.
In Monterrey, Mexico, Priscila Martinez said, her grandparents "don't take precautions like they should." The 19-year-old and her mother left Mexico for Canton when she was 11. Now at the University of Michigan, the junior political science major said she didn't know what flu was until she came to the United States.
"We don't get vaccines," she said. "We don't talk about it."
David Hayes-Bautista, an epidemiologist at the University of California, Los Angeles, who studies Latino health issues, said illnesses like flu are top-10 killers in Mexico. It's a perception problem, he said.
Former Mexican minister of health Julio Frenk said recently that about 10,000 people die of flu complications each year in Mexico, making its death rate slightly less than in the United States, where 36,000 of the 306 million Americans die each year.
Even with what has been learned since the outbreak began, Victoria Pardo , a 22-year-old math major from Dearborn at Wayne State University, still is rethinking her August trip to Chihuahua, a border state where the third-generation Mexican American has been a missionary.
"The thought of even being there worries me and my family," she said.
Seven further UK swine flu cases
Seven new swine flu cases in the UK have been confirmed, the Department of Health has said.
A spokeswoman said all the people diagnosed were in England, bringing the total in the UK to 55.
She added that the cases involved two adults and four children in London and an adult in the east of England.
"So far, all infections in the UK have been mild, and cases have been diagnosed and treated early," the spokeswoman said.
Laboratory investigation
A Health Protection Agency (HPA) spokeswoman said the adult in the east of England and one of the London adults had been in contact with individuals who had previously been confirmed with swine flu.
The other adult in London and all four children "were swabbed last week and may have acquired their infection before the closure of their school", she said.
She added that anti-viral drugs had been given to all children and staff as a precaution, and all symptomatic patients were recovering at home.
According to the HPA, a further 384 cases were under laboratory investigation as of 1500BST on Sunday.
Of the 55 cases in the UK, 50 have been confirmed in England and five in Scotland.
A spokeswoman said all the people diagnosed were in England, bringing the total in the UK to 55.
She added that the cases involved two adults and four children in London and an adult in the east of England.
"So far, all infections in the UK have been mild, and cases have been diagnosed and treated early," the spokeswoman said.
Laboratory investigation
A Health Protection Agency (HPA) spokeswoman said the adult in the east of England and one of the London adults had been in contact with individuals who had previously been confirmed with swine flu.
The other adult in London and all four children "were swabbed last week and may have acquired their infection before the closure of their school", she said.
She added that anti-viral drugs had been given to all children and staff as a precaution, and all symptomatic patients were recovering at home.
According to the HPA, a further 384 cases were under laboratory investigation as of 1500BST on Sunday.
Of the 55 cases in the UK, 50 have been confirmed in England and five in Scotland.
Japan ramps up swine flu checks
Japan intensified follow-up checks to prevent the spread of swine flu Sunday after confirming its first cases of the virus in four Japanese recently returned from a trip to North America.
The health ministry announced early Sunday that a male high school student had tested positive for the A(H1N1) influenza virus in Japan's fourth confirmed case.
He was among 49 passengers who arrived at Tokyo's Narita airport on a flight from the US city of Detroit on Friday. The group was quarantined because they were seated close to the first three Japanese people found to have the virus.
They were taken to a hotel near the airport to be isolated for 10 days.
The ministry said it was also monitoring the condition of other people who had already entered Japan after arriving on the same Northwest Airlines flight. They have spread to 26 of the country's 47 prefectures.
"We will continue observing the health conditions of the 163 people by telephone calls and through their local public health centres for 10 days," said Yukiko Nakatani, an official at the ministry's medical department.
"We cannot say anything definite about the possibility of the disease spreading domestically," she told AFP.
The ministry said on Saturday that a 46-year-old male teacher and two of the student's male schoolmates, both 16, who had been on a study trip to Canada, tested positive for the virus. They were from a high school in Osaka, western Japan.
They stayed in Oakville, west of Toronto, from April 24 until last Thursday.
There were 409 passengers and crew members aboard the flight and many of them have travelled on to other countries after changing planes at Narita.
Nakatani said the conditions of the first three patients had improved.
"The teacher's body temperature is slightly high but those of the students have returned to normal," she said, adding that the fourth patient was in a "stable condition."
Japanese newspapers, warning the domestic spread of swine flu might be inevitable, urged the government Sunday to take effective measures against the viral infections.
The business daily Nikkei said, "It will become important hereafter to keep track of virus carriers as soon as possible and locally contain secondary infections."
Major daily Mainichi Shumbun called on the government to "prepare for a long-running battle" against the disease.
Japan has been on high alert as one of the year's busiest travel periods came to an end, the "Golden Week" of public holidays when tens of millions travel domestically and overseas.
The health ministry announced early Sunday that a male high school student had tested positive for the A(H1N1) influenza virus in Japan's fourth confirmed case.
He was among 49 passengers who arrived at Tokyo's Narita airport on a flight from the US city of Detroit on Friday. The group was quarantined because they were seated close to the first three Japanese people found to have the virus.
They were taken to a hotel near the airport to be isolated for 10 days.
The ministry said it was also monitoring the condition of other people who had already entered Japan after arriving on the same Northwest Airlines flight. They have spread to 26 of the country's 47 prefectures.
"We will continue observing the health conditions of the 163 people by telephone calls and through their local public health centres for 10 days," said Yukiko Nakatani, an official at the ministry's medical department.
"We cannot say anything definite about the possibility of the disease spreading domestically," she told AFP.
The ministry said on Saturday that a 46-year-old male teacher and two of the student's male schoolmates, both 16, who had been on a study trip to Canada, tested positive for the virus. They were from a high school in Osaka, western Japan.
They stayed in Oakville, west of Toronto, from April 24 until last Thursday.
There were 409 passengers and crew members aboard the flight and many of them have travelled on to other countries after changing planes at Narita.
Nakatani said the conditions of the first three patients had improved.
"The teacher's body temperature is slightly high but those of the students have returned to normal," she said, adding that the fourth patient was in a "stable condition."
Japanese newspapers, warning the domestic spread of swine flu might be inevitable, urged the government Sunday to take effective measures against the viral infections.
The business daily Nikkei said, "It will become important hereafter to keep track of virus carriers as soon as possible and locally contain secondary infections."
Major daily Mainichi Shumbun called on the government to "prepare for a long-running battle" against the disease.
Japan has been on high alert as one of the year's busiest travel periods came to an end, the "Golden Week" of public holidays when tens of millions travel domestically and overseas.
Developments on swine flu worldwide
Key developments on swine flu outbreaks, according to the U.S. Centers for Disease Control and Prevention, the World Health Organization and government officials:
Deaths: Global total of 53 — 48 in Mexico; three in the U.S.; one in Canada and one in Costa Rica. One of those who died in the U.S. was a toddler from Mexico. Officials said the Canadian, U.S. and Costa Rican victims also had other underlying medical conditions.
Confirmed cases, according to WHO and CDC: more than 4,500 in 29 countries, including at least 1,626 in Mexico, at least 2,532 in the United States and 280 in Canada.
Third U.S. death was a man in his 30s in Washington state, where health officials said he had underlying heart conditions.
Japan reported its first four cases: a teacher and three students who had been on a high school trip to Canada. Australia reported its first confirmed case Saturday.
WHO says up to 2 billion people could be infected by swine flu if outbreak turns into pandemic over months or years. But WHO flu chief Keiji Fukuda says it's too early to tell how widespread or severe the outbreak will become.
President Barack Obama sought to reassure Hispanics that swine flu won't lead to epidemic of discrimination in the United States just because Mexico has been the center of the outbreak.
Mexico's U.N. envoy says nations need common rules for responding to flu outbreaks to prevent discrimination and unfair trade restrictions; says Mexicans unfairly singled out.
High schools, universities, dance halls, movie theaters and bars have reopened across Mexico. Primary schools will reopen next week.
CDC says only about 10 percent of Americans with swine flu are believed to have gotten it during trips to Mexico.
Deaths: Global total of 53 — 48 in Mexico; three in the U.S.; one in Canada and one in Costa Rica. One of those who died in the U.S. was a toddler from Mexico. Officials said the Canadian, U.S. and Costa Rican victims also had other underlying medical conditions.
Confirmed cases, according to WHO and CDC: more than 4,500 in 29 countries, including at least 1,626 in Mexico, at least 2,532 in the United States and 280 in Canada.
Third U.S. death was a man in his 30s in Washington state, where health officials said he had underlying heart conditions.
Japan reported its first four cases: a teacher and three students who had been on a high school trip to Canada. Australia reported its first confirmed case Saturday.
WHO says up to 2 billion people could be infected by swine flu if outbreak turns into pandemic over months or years. But WHO flu chief Keiji Fukuda says it's too early to tell how widespread or severe the outbreak will become.
President Barack Obama sought to reassure Hispanics that swine flu won't lead to epidemic of discrimination in the United States just because Mexico has been the center of the outbreak.
Mexico's U.N. envoy says nations need common rules for responding to flu outbreaks to prevent discrimination and unfair trade restrictions; says Mexicans unfairly singled out.
High schools, universities, dance halls, movie theaters and bars have reopened across Mexico. Primary schools will reopen next week.
CDC says only about 10 percent of Americans with swine flu are believed to have gotten it during trips to Mexico.
2 More Swine Flu Deaths
Two additional deaths attributed to swine flu were reported over the weekend, with both victims suffering from other health conditions.
China also reported its first suspected case of the flu, according to The Associated Press. On Sunday, the World Health Organization reported that there were 4,379 cases of the A (H1N1) virus in 29 countries. In the United States, the Centers for Disease Control and Prevention reported 2,532 cases in 44 states and the District of Columbia.
In Costa Rica, a 53-year old man died after contracting the virus, that country’s Health Ministry said, adding that he also suffered from diabetes and chronic lung disease.
In the state of Washington, an American man in his 30’s with underlying health issues and viral pneumonia died, according to that state’s health department. So far, three people have died of swine flu in the United States, the first victim a Mexican toddler who died in a Houston hospital.
The unidentified Washington man was in his 30’s and lived in Snohomish County, north of Seattle. The Washington Sate Department of Health said on its Web site that he had “underlying heart conditions and died last week with what appears to be complications” of swine flu.
He began showing symptoms on April 30, The A.P. reported, and was treated with anti-viral medication. Dr. Gary Goldbaum, Snohomish Health District medical director, said medical officials had not been able to isolate any “risk factors” for the man to identify where he might have been exposed.
Underlying health conditions appear to put swine flu victims at greater risk of hospitalization or death, the World Health Organization and the Centers for Disease Control and Prevention said on Friday. Officials stressed that their observations were preliminary.
All three reported deaths in the United States to this point have involved victims with health problems, as has the single fatal case in Canada. More than 100 people have been hospitalized because of the virus in the United States. But most of the victims in Mexico, the center of the outbreak where 48 people with swine flu have died, have been adults aged 20 to 49 with no known complicating factors.
China also reported its first suspected case of the flu, according to The Associated Press. On Sunday, the World Health Organization reported that there were 4,379 cases of the A (H1N1) virus in 29 countries. In the United States, the Centers for Disease Control and Prevention reported 2,532 cases in 44 states and the District of Columbia.
In Costa Rica, a 53-year old man died after contracting the virus, that country’s Health Ministry said, adding that he also suffered from diabetes and chronic lung disease.
In the state of Washington, an American man in his 30’s with underlying health issues and viral pneumonia died, according to that state’s health department. So far, three people have died of swine flu in the United States, the first victim a Mexican toddler who died in a Houston hospital.
The unidentified Washington man was in his 30’s and lived in Snohomish County, north of Seattle. The Washington Sate Department of Health said on its Web site that he had “underlying heart conditions and died last week with what appears to be complications” of swine flu.
He began showing symptoms on April 30, The A.P. reported, and was treated with anti-viral medication. Dr. Gary Goldbaum, Snohomish Health District medical director, said medical officials had not been able to isolate any “risk factors” for the man to identify where he might have been exposed.
Underlying health conditions appear to put swine flu victims at greater risk of hospitalization or death, the World Health Organization and the Centers for Disease Control and Prevention said on Friday. Officials stressed that their observations were preliminary.
All three reported deaths in the United States to this point have involved victims with health problems, as has the single fatal case in Canada. More than 100 people have been hospitalized because of the virus in the United States. But most of the victims in Mexico, the center of the outbreak where 48 people with swine flu have died, have been adults aged 20 to 49 with no known complicating factors.