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If the U.S. swine flu epidemic isn’t over, it certainly looks as if it’s on its last legs. While federal health officials are not ready to declare the threat has passed and the outbreak has run its course, they did report Friday that for the fourth week in a row, no states had widespread flu activity. U.S. cases have been declining since late October.
One U.S. expert said the epidemic has “one foot in the grave,” and there are many reasons to believe there won’t be another wave later in the year.
For one thing, the virus has shown no signs of mutating. The vaccine against it is effective. And roughly half the people in the U.S. probably have some immunity because they were infected with it or got vaccinated.
The World Health Organization is witnessing an international decline as well, and is discussing criteria for declaring the pandemic over. Britain this week shut down its swine flu hot line, which was set up to diagnose cases and give out Tamiflu.
“Clearly, the last four weeks have been one of the quietest January flu seasons I can remember in my career,” said Michael Osterholm, a prominent expert on global flu outbreaks with the University of Minnesota.
Since its emergence last April, swine flu has caused an estimated 15,200 deaths worldwide, mostly in the U.S. — a much lower number than initially feared. The positive outcome is primarily because the virus didn’t mutate into a deadlier form.
Even so, experts have praised the actions of the U.S. and Mexican governments and scientists who quickly developed an effective vaccine.
Criticizing the government for its intense response would be like chastising officials for building dikes in New Orleans to withstand a Category 5 hurricane and then seeing only a Category 3 come ashore, Osterholm said.
“The government did not overreact,” said University of Michigan flu expert Dr. Arnold Monto, echoing Osterholm’s point.
Whether it will stay quiet for the rest of the winter is hard to say, but some experts are beginning to lean that way.
“If it’s not dead, it’s weakening fast. It’s got one foot in the grave,” said Dr. William Schaffner, a flu authority at Vanderbilt University.
A poll released Friday by the Harvard School of Public Health found that 44 percent of Americans believe the outbreak is over.
The Centers for Disease Control and Prevention released numbers Friday showing most states continued to have only occasional flu activity last week. However, only three states had absolutely no reports, and a CDC official cautioned that swine flu is still around and is likely to keep infecting people for weeks or months to come.
“We don’t seem to be seeing the disappearance of this virus,” said the official, Dr. Anne Schuchat.
Whether there will be another wave of swine flu — as was seen in the spring last year and again in the early fall — is a much harder question, she added.
Her comments reflect a raging debate among scientists. One expert told The Associated Press he thinks a spike in H1N1 cases is likely by May, though perhaps a smaller one than last fall. Another said he did not expect another spike. A third predicted another wave, but not until next fall at the earliest. A fourth refused to even guess.
An estimated 70 million Americans have been vaccinated against swine flu through a government campaign that started in October. Counting those who have already been infected and others who were vaccinated, perhaps 40 percent of the public has some immunity to the virus.
However, that means at least half of Americans don’t have immunity, and there are many places that have not been hit hard by swine flu yet, some experts noted.
Also, this is a global disease that can move quickly through air travel, and much of the rest of the world is not vaccinated, Osterholm pointed out.
Experts give health officials generally good marks for their handling of the pandemic, even with months of delays in the production of swine flu vaccine.
About 60 percent of the 1,400 adults in the Harvard poll said U.S. public health officials did a good or excellent job in dealing with the pandemic. More than half said the government devoted the right amount of attention to the outbreak.
The telephone survey was done in late January and had a margin of error of plus or minus 3.2 percentage points.
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Associated Press Medical Writer Maria Cheng contributed to this report from London.
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The new swine flu is scary, no doubt about it. But here’s the information you need to better understand the illness and the ways you can protect yourself and your family from infection.
Understanding the Swine Flu Virus
Human influenza, or the “flu,” is a viral infection that usually occurs seasonally and is transmitted between people. The viruses are categorized into two major types, A and B, and subtypes, named H and N. The current swine flu is a new type of influenza A virus, H1N1, which has not previously been seen. This strain is unusual in that it appears to be a cross between strains that infect swine, birds and human beings. While this new strain may yet present some surprises, we know a lot about how influenza is transmitted and how to slow or break that cycle.
The main way that influenza viruses are spread is person to person via the respiratory droplets of coughs and sneezes. The virus is transmitted when these infected droplets land on the mouth or nose of people nearby or when people touch respiratory droplets on another person or an object, and then they touch their mouth or nose or rub their eyes before washing their hands. Swine flu is not spread by eating pork or other food, and pigs pose little risk of viral transmission.
Protecting Yourself and Your Family from Infection
The bottom line of protecting yourself is to practice good hygiene and avoid coming into contact with the virus.
Keep your hands away from your face or wash them first. Stay away from crowds. Avoid contact with sick people if you can. If you can’t, wash your hands often with soap and water. Be sure to use a paper towel to turn off the faucet handles so as not to recontaminate your hands. The same paper towel precautionary measure applies to doorknobs. If you can’t wash your hands, use an alcohol-based hand sanitizer with at least 60 percent alcohol.
Cover your mouth when you cough and sneeze. Teach your family to do the same and to discard used tissues promptly. If no tissues are available, it is better to cough or sneeze into your sleeve than your hand. They should wash their hands immediately, before they contaminate other surfaces with infective secretions.
Keep ill family members away from others at home and stay at home unless medical care is needed. Masks are most effective when worn by infected people to prevent the spread of the virus, so if you are infected and you must go out, wear a mask to reduce the transmission of infected droplets to others. While masks are not effective against small viral particles that may be airborne, and airborne transmission may occur, large infective droplets are probably a major factor and the one that a mask can best protect against. Wear a mask if you are within six feet of an ill person. N-95 masks must fit tightly to work effectively. Don’t worry if you don’t have an N-95 or a fancy surgical mask. The key to prevention is to keep droplets away from your nose, mouth and eyes. You can use a cloth bandana or similar accessory to cover your nose and mouth. Change paper or cloth masks frequently. (In hospitals, N-95 masks are recommended because of higher exposure rates.)
Seek medical care promptly if you become ill with flu-like symptoms-fever, generalized aches, sore throat, cough, runny nose, vomiting, diarrhea and lethargy-especially if you are having trouble breathing. The antiviral medicines Tamiflu and Relenza are quite effective if taken within the first 48 hours of your symptoms’ appearance. If you are exposed to the new 2009H1N1 virus, you might also benefit from prophylactic antivirals to prevent infection, especially if you have underlying health problems. Check with your doctor.
Warning: Do not give aspirin (acetylsalicylic acid) to children or teenagers who have the flu; this can cause the serious and possibly fatal Reye’s syndrome. NSAIDS (nonsteroidal anti-inflamatory drugs) such as ibuprofen (Advil, Motrin), naproxen (Naprosyn, Midol) and acetominophen (Tylenol) are safe to administer for their symptomatic relief.
Remember, staying away from crowds and using good hygiene can help you prevent the contraction of many flu illnesses and give you some measure of reassurance during this flu outbreak.
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ATLANTA – Let us give thanks — and pass the Purell.
Your family might be sharing more than turkey and pumpkin pie this Thanksgiving. Swine flu may also be on the table — and at crowded airports and shopping malls.
Just as the pandemic seems to be waning around the country, some health officials are worried that holiday gatherings could lead to more infections. So the government has launched a new travel-health campaign.
“It’s important to remember the things that everybody can do to stay healthy,” said Dr. Beth Bell of the Centers for Disease Control and Prevention.
Thanksgiving is typically followed by at least a modest bump in early seasonal flu cases, according to reports from the past few years. But this, of course, is not a typical year. Swine flu is a new virus that accounts for nearly all flu cases right now.
Despite weeks of declining infections, health officials are staying vigilant. The federal government is putting up posters in airports, seaports and border crossings in time for Thanksgiving. The campaign also includes advertisements with slogans such as “Stop, Wash & Go.”
The CDC urges people to travel only if they are well, get vaccinated against swine and seasonal flu, wash their hands often, and cover coughs and sneezes with a tissue or sleeve.
Some 33 million Americans are expected to hit the nation’s highways over the Thanksgiving holiday, a slight increase from last year. About 2.3 million more will travel by airplane.
The elbow-to-elbow conditions expected on many flights may pose more of an infection threat than a runny-nosed tike at the other end of a Thanksgiving dinner table. One CDC official even suggested asking that a sick passenger be moved to another part of a plane.
But that’s not likely to happen on a crowded airliner or bus, and it isn’t much of a solution anyway, said a few people waiting at Atlanta’s downtown Greyhound station on Tuesday morning.
“That’s just putting it next to somebody else,” said Judd Nelson, 39, waiting to start a two-day bus trip to Phoenix.
Nelson had not been vaccinated against swine flu, and he did not have any hand sanitizer. He was resigned to his fate if someone with swine flu happens to be aboard his bus.
“The way I look at it is, if I get it, I’m going to get it no matter what,” he said.
Swine flu has sickened an estimated 22 million Americans, hospitalized about 98,000 and killed 4,000 since it was first identified last April. It is similar to seasonal flu but poses a much bigger threat to children and young adults.
Usually, seasonal flu is just getting going in late November, and holiday get-togethers allow illness to jump from small pockets to other parts of the country. Swine flu, in contrast, has been widespread for months.
“It’s not like we expect to see a bunch of infected people going to uninfected cities and towns,” said Andrew Pekosz, a flu expert at Johns Hopkins University.
The swine flu pandemic hit in two waves: first in the spring, then a larger wave that started in the late summer.
For the past three weeks, fewer states have been reporting widespread cases. School closings have dropped to the point that there were none on Monday — the first time that’s happened since late August — though there were six on Tuesday, according to the U.S. Department of Education.
But there are still plenty of ill people — as many as during the peak of many regular flu seasons, CDC officials say.
Indeed, disease trackers are quick to say that flu is unpredictable. A variety of things could happen, including a third wave or a mutation that could make the virus more deadly or less susceptible to medicines.
“We really don’t know what the trajectory is going to be,” said Bell, a CDC epidemiologist who has been a leader in the agency’s swine flu response.
Seasonal flu usually emerges at this time of year, but some experts think swine flu will muscle aside the seasonal viruses. That probably will not be known until next month, said Dr. Richard Whitley, an infectious diseases specialist at the University of Alabama at Birmingham.
At New York’s Pennsylvania Station, Katie Almroth was waiting to board a train Tuesday with her 11-month-old daughter Anna, who’s been vaccinated for seasonal flu but not for swine flu. They were headed to Harrisburg, Pa., to visit relatives for Thanksgiving.
The 33-year-old nurse from Jersey City, N.J., said she was not worried about traveling during the swine flu pandemic, but felt more comfortable on a train than an airplane with her daughter.
“I must admit I did bring little wipes along,” said Almroth, showing the antiseptic wipes she had tossed in her bag with small bottles of hand sanitizer.
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WASHINGTON (AFP) – The US Food and Drug Administration (FDA) on Friday warned consumers to avoid buying medicines online to treat swine flu, saying one such product contained nothing more than talc and over-the-counter fever-reducer.
The FDA raised the warning after some of its investigators purchased and analyzed products represented online as Tamiflu (oseltamivir), one of the anti-viral medicines that has been shown to be effective against A(H1N1) flu.
“One of the orders, which arrived in an unmarked envelope with a postmark from India, consisted of unlabeled, white tablets taped between two pieces of paper,” the food and drug safety watchdog said.
“The tablets were found to contain talc and acetaminophen (paracetamol), but none of the active ingredient oseltamivir,” it said.
In buying several of the products, the FDA investigators were not asked to produce a doctor’s prescription.
The two antiviral drugs approved by the FDA for treatment and prophylaxis of the 2009 A(H1N1) influenza virus, Tamiflu and Relenza, require prescriptions.
“Medicines purchased from websites operating outside the law put consumers at increased risk due to a higher potential that the products will be counterfeit, impure, contaminated or have too little or too much of the active ingredient,” FDA Commissioner Margaret Hamburg said.
Patients who buy prescription drugs from websites run an “increased risk of suffering life-threatening adverse events, such as side effects from inappropriately using prescription medications, dangerous drug interactions, contaminated drugs, and impure or unknown ingredients found in unapproved drugs,” the FDA said.
Bogus drugs are more common in times of a public health emergency, such as an influenza outbreak, when unlicensed manufacturers take advantage of high demand for medications and try to turn a quick profit, the FDA warned.
It’s possible to buy Tamiflu online, however prescription is required.
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ST. LOUIS – Hundreds of Americans in eight cities are lining up for experimental swine flu shots in a race to get a vaccine out in case the new flu virus regains strength this fall and winter.
Sharon Frey, who is leading the government-funded testing at Saint Louis University, said scientists have been working late nights and weekends to organize the studies and recruit volunteers.
“Typically it takes a year to do this,” said Frey, an infectious diseases expert. “I can tell you we’re working at breakneck speed.”
About 2,800 people will participate in the government-led studies. Saint Louis University will test 200 adults and 200 children. Also under way are separate studies by five flu vaccine manufacturers under contract with the government.
Health officials expect to have about 160 million doses available this fall, with the first batch sometime in September. The studies will test the safety and effectiveness of vaccines developed by drug makers and help determine dosage and whether it can be given with a seasonal flu shot.
Participants will be given different combinations of two swine flu vaccines made by drug makers Sanofi Pasteur and CSL Limited and a seasonal flu vaccine.
Frey said the data will be turned around quickly for review by the Food and Drug Administration.
It’s possible the government will begin a public vaccination campaign before all of the work of the trials is complete, Dr. Anne Schuchat has said. She oversees the flu vaccination programs at the Centers for Disease Control and Prevention.
Health officials are haunted by the swine flu vaccine campaign in 1976, which was stopped after unexpectedly high numbers of patients suffered a paralyzing condition called Guillain-Barre Syndrome. While it’s not clear the vaccine was to blame, the government wants to carefully monitor people who get the new vaccine for any problems.
Nicholas Sarakas, 25, of St. Peters, Mo., is among the vaccine volunteers. As a young adult, he’s among the groups targeted for the swine flu vaccine; swine flu has been harder on younger people than their elders.
“I thought, ‘I’ll end up getting a flu shot anyway,’” he said. “Somebody has to be the first person to try it.”
The other study sites are Baylor College of Medicine in Texas, Children’s Hospital Medical Center in Cincinnati, Emory University, Group Health Cooperative in Seattle, University of Iowa, University of Maryland School of Medicine and Vanderbilt University.
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ATLANTA – In a startling measure of just how widely a new disease can spread, researchers accurately plotted swine flu’s course around the world by tracking air travel from Mexico.
The research was based on an analysis of flight data from March and April last year, which showed more than 2 million people flew from Mexico to more than 1,000 cities worldwide. Researchers said patterns of departures from Mexico in those months varies little from year to year; swine flu began its spread in March and April this year.
Passengers traveled to 164 countries, but four out of five of those went to the United States. That fits with the path of the epidemic a year later. The findings were reported Monday in the New England Journal of Medicine.
The research shows promise in forecasting how a new contagion might unfold, indicated one government health official who praised the work.
“We share a common interest in this issue: If we map the global airline distribution network, can we anticipate, once a virus emerges, where it is likely to show up next?” asked Dr. Martin Cetron of the U.S. Centers for Disease Control and Prevention. He leads CDC’s division of global migration and quarantine.
The new swine flu virus was first reported in the United States in mid-April, but the first large outbreak was in Mexico at about the same time. Health officials believe cases of the new virus were circulating in Mexico in March.
Scientists have long assumed a relationship between air travel and spread of the virus. But the new research for the first time confirmed the relationship, said Dr. Kamran Khan, who led the study. He is a researcher at St. Michael’s Hospital in Toronto.
For years, Khan and his colleagues have been working on a system to use air travel information quickly to determine how a new contagion is likely to spread around the world.
Their data sources include the International Air Transport Association, an international trade association representing 230 airlines and the vast majority of scheduled international air traffic.
The study showed the majority of passengers flew to the United States, with Canada a distant second and France a more distant third.
More than 90 percent of the time, Khan and his colleagues accurately matched air traffic volumes to which countries did and did not suffer swine flu outbreaks as a result of air traffic.
The top 11 destination cities from Mexico were all in the United States. Los Angeles was the leader, receiving about 9 percent of all passengers from Mexico, and New York City was second, with about 5 percent.
In contrast, the only South American entry in the top 40 destination cities was Buenos Aires, at No. 22. Passengers were even fewer when it came to cities in neighboring Guatemala and other Central American countries.
The data show not only how disease spreads out of Mexico, but also that air travel is mainly among more industrialized countries, experts said.
A second study released by the journal found a sharp rise in pneumonia cases in non-elderly Mexicans from late March to late April. Normally, only about a third of severe pneumonia cases in Mexico are in people ages 5 to 59. But during the recent swine flu outbreak, more than 70 percent were in that younger age group.
The study seems to support plans to target swine flu prevention efforts to the young, experts said.
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GENEVA – Dozens of countries urged the World Health Organization to change its criteria for declaring a pandemic, saying the agency must consider how deadly a virus is — not just how far it spreads across the globe.
Fearing a swine flu pandemic declaration could spark mass panic and economic devastation, Britain, Japan, China and others asked the global body on Monday to tread carefully before raising its alert. Some cited the costly and potentially risky consequences, such as switching from seasonal to pandemic vaccine, even though the virus so far appears to be mild.
Although no formal changes were made Monday, WHO said it would listen to its members’ requests.
“It’s certainly something we will look at very closely,” said Dr. Keiji Fukuda, WHO’s flu chief.
The alert for swine flu is now at phase 5, which means the virus is spreading unchecked inside at least two countries in a single region. Under the existing rules, phase 6 indicates outbreaks in at least two different regions of the world and that a pandemic is under way.
“We need to give you and your team more flexibility as to whether we move to phase 6,” Britain’s Health Secretary Alan Johnson told WHO Director-General Dr. Margaret Chan, a public health veteran who has made combatting the outbreak her top priority since the new virus appeared in North America last month.
Chan warned that swine flu could pose a grave threat to humanity even though the fatality rate is low, with 76 known deaths out of 8,829 confirmed cases in 40 countries. That total does not include Greece, which reported its first confirmed case on Monday.
“This virus may have given us a grace period, but we do not know how long this grace period will last,” Chan said. “No one can say whether this is just the calm before the storm.”
Japan reported the largest jump from just four cases over the weekend to more than 170 cases, health officials said Tuesday. Most involved teenagers who had not traveled overseas.
Spain and Britain have the highest numbers of cases in Europe, reporting 103 and 101 cases, respectively.
A pandemic announcement would likely have severe economic consequences: It could trigger expensive trade and travel restrictions such as border closures, airport screenings and quarantines.
Governments also fear mass panic, social disruption and overwhelmed health systems. Extraordinary measures such as large-scale pig slaughters like the recent one in Egypt could be taken, even if they aren’t scientifically justified.
Mexico, which has suffered the most deaths and virtually shut down its economy for several days in response to the outbreak, urged WHO to reconsider its pandemic scale.
“People don’t understand what 4, 5 or 6 means,” Mexico’s Health Minister Jose Angel Cordova told reporters. “They think that when you go to a higher level things are worse.”
U.S. Health and Human Services Secretary Kathleen Sebelius told The Associated Press she wanted more information on the proposal before taking a position, but she was impressed how many countries supported it. Still, in a speech to the assembly she noted that each day 26,000 children will die from poverty and preventable diseases. Swine flu is a long way from causing that kind of devastation.
So far the virus appears to be mild, though scientists are concerned that many of the more severe symptoms have turned up in younger people, especially in Mexico. Flu is normally most dangerous to babies and the elderly.
WHO chief Chan noted that the disease could combine with other flu strains, including the lethal H5N1 bird flu virus which hasn’t spread much among humans.
The signal for starting pandemic vaccine production has yet to be given, but it is essential that countries use their stockpiles of drugs wisely, she said. WHO has said two anti-viral drugs, Tamiflu and Relenza, have been effective against the new swine flu.
“It is absolutely essential that countries do not squander these precious resources through poorly targeted measures,” Chan said.
Chan and U.N. Secretary-General Ban Ki-moon are scheduled to meet with senior representatives of pharmaceutical companies Tuesday to discuss the vaccine question. The U.N. declined to name the companies but major vaccine producers include Sanofi-Aventis, GlaxoSmithKline and Baxter International.
Key issues include: how soon can a pandemic vaccine be produced, and how much of it will be available to each country. Many governments, including Britain, have already signed large advance orders, potentially depriving poorer countries of a chance to buy their own stock.
AmericanHealthOptions reminds that most common medication for fighthing against swine flu is Tamiflu.
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WASHINGTON – A flu virus is a powerhouse of evolution, mutating at the maximum speed nature allows. A mild virus can morph into a killer and vice versa.
One change already made this year’s swine flu more of a problem, helping it spread more easily among people. The big question is: What mutations are next? That’s why scientists are watching it so closely.
“There are no rules to flu viruses; they are just so mutable,” said Dr. Paul Glezen, a flu epidemiologist at the Baylor College of Medicine in Houston. “The fact that it changes all the time really confounds our efforts to control it.”
Think of flu’s evolution like a family tree: In the current flu’s distant ancestry are last century’s three pandemics. But its more immediate relatives are swine flu strains that were no big deal to humans.
The good news right now is that this flu has lost some of the most dangerous genetic traits of past pandemics. The bad news is that it’s gained something its parents didn’t have: the ability to spread from human to human.
Flu reproduces about every eight hours, said Dr. Raul Rabadan, professor of computational biology at Columbia University. That means this morning’s flu is a parent by the afternoon, a grandparent by the evening, and a great-grandparent by the next day.
Instead of complex double-helix DNA — nature’s basic biological instruction book — flu has a simpler, single strand of genetic code. Normal DNA has a spellcheck-like system that reduces mistakes in replicating the code; the flu virus does not. So mutations come more often. If the mutations are good for the virus, they multiply, and voila, you have a new and sometimes nastier flu.
Scientists are trying to piece together swine flu’s ever-changing genome, its genetic ancestors and the random mutations that in this instance turned a simple pig disease into something that scares billions.
They also don’t know how the virus is going to mutate next.
In the world’s most devastating global flu epidemic in 1918, the first wave of cases in the spring were mild. Then, the virus evolved and came back in the fall as a strain that proved truly deadly, flu experts say. So scientists today are watching to see if that could happen again.
Also troubling is the possibility that this virus could develop resistance to anti-flu drugs, and flu trackers are watching for such changes, Centers for Disease Control and Prevention flu chief Dr. Nancy Cox said.
It’s impossible to know where this swine flu strain began exactly, Cox said. But flu trackers do have clues to its closest ancestral genes.
“Its two parents were swine viruses that we know and love,” said virologist Dr. Richard Webby, a researcher at St. Jude Children’s Research Hospital in Memphis, Tenn.
The mother of the swine flu was a surprising genetic event that went unnoticed except by a few scientists a little over a decade ago. Three influenza strains — some pig, some bird, some human — combined in pigs to form two new strains of swine flu. This new flu was unusual. Virus hunters called it a “triple reassortment.”
That 1998-99 flu in pigs first hit a farm in North Carolina, then spread to Iowa, Texas, Oklahoma and eventually to at least 23 states. No more than 4 percent of the swine died. But the disease was in more than one-quarter of tested pigs. A handful of people who were in close contact with the hogs got slightly sick when they caught this flu from pigs, but they didn’t die and didn’t spread it to others.
In 2005, a 17-year-old Wisconsin boy caught that triple reassortment flu virus from “respiratory secretions” of a pig he had been helping his brother-in-law butcher, according to the CDC. He recovered and didn’t pass it on to others.
There have been about 10,000 generations of that virus since. Six of the eight genetic segments of the current swine flu can be traced to that triple combination, Rabadan said.
The rest of the swine flu parentage is more of a mystery. The other two of the eight genetic segments can be traced to pig viruses in Europe and Asia that were seen from time to time in the 1990s, Rabadan said. Scientists don’t quite know if those other two segments combined with the triple reassortment at the same time or separately.
How the triple reassortment genes and the European and Asian genes met and mixed is not known, Webby said.
The three global flu epidemics of the past, including the 1918 event, all passed on traits to ancestors of this flu, Rabadan said. But there have been many changes in the thousands of generations since.
A specific gene for virulence that was seen in the 1918, 1957 and 1968 pandemics was notably absent in this swine flu, said Dr. Peter Palese, a prominent flu researcher for Mount Sinai Medical Center in New York. He said when he removed that gene from other viruses of the past, they weren’t as dangerous.
Rabadan suggests the way to think of this flu is like a homemade car with parts from different vehicles. The parts have all been in several different vehicles before. Sometimes the combination of parts is a dud and the car doesn’t move. And sometimes you get a race car. A pandemic is a race car.
All eight of the new flu’s genetic segments have been in different viruses before. But this is the first time this specific combination has been seen. The big question is: Why is this particular swine virus spreading so fast among people when past swine viruses haven’t?
One possibility is that it’s just this particular combination of the eight parts that makes it spread among people, Webby said. But a more logical explanation is that a small mutation within the individual genetic segments changed things.
These tiny changes are possible because there are about 13,000 individual letters, or bases, in the flu genetic code, Rabadan said. That’s tiny compared to more than 3 billion in humans.
One prime suspect is the surface protein hemagglutinin, the “H” in the virus’ H1N1 name. It is “probably the most important gene determining virulence and immunological characteristics,” according to Palese.
In flu viruses, scientists have so far identified 16 hemagglutinins. Only three — H1, H2 and H3 — commonly infect humans. The other surface protein, neuraminidase, has nine variations. Palese said scientists are seeing more different types of flu strains because of better surveillance and increases in bird, pig and human populations.
“These genetic processes of mutation and genetic reassortment occur all the time,” he said, “and every once in a time, it’s a lottery winner.”
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MEXICO CITY, (AFP) – World health officials stepped up warnings of a possible pandemic of swine flu as governments released millions of antiviral drugs and the number of cases rose, spreading into Europe.
With the likely death toll in Mexico, the epicenter of the outbreak, now standing at 149, the World Health Organization (WHO) raised its flu pandemic alert level from three to four.
While the increase marked a “significant step towards pandemic influenza, it’s also a phase which says we are not there yet,” said Keiji Fukuda, acting WHO assistant-general for health, security and the environment.
Fukuda warned “that in this age of global travel where people move around in airplanes so quickly, there is no region to which this virus could not spread.”
The number of confirmed cases in the United States more than doubled on Monday to 44 and Britain and Spain both said they had registered patients sick with swine flu, the first cases in Europe.
UN chief Ban Ki-moon warned the new multi-strain virus, which is believed to be a mix of a human flu virus and an avian flu that first came from swine, risked triggering a global pandemic.
“We are concerned that this virus could cause a new influenza pandemic. It could be mild in its effect or potentially be severe,” Ban told reporters.
“We don’t know yet which way it will go but we are concerned that in Mexico most of those who died were young and healthy adults.”
Influenza caused three epidemics during the 20th century, the worst being the Spanish flu between 1918 and 1919 that killed at least 40 million people, according to the WHO.
Mexico, which was rocked by a 5.6 magnitude earthquake on Monday, said the number of confirmed and suspected deaths from the flu had now risen to 149, as other countries urged against non-essential travel to the tourism hotspot.
Schools across Mexico have been closed until May 6 in a bid to stop the spread of the flu, which has sickened more than 1,600 people.
“We’re in the decisive moment of the crisis. The number (of deaths) will continue rising,” Health Minister Jose Angel Cordova added.
Europe’s first confirmed case was reported in Spain, where 26 suspected cases were being probed, while two people were found to have the disease in Britain and dozens more potential cases were being checked in seven European Union member states.
Fears the disease could further strain the already-embattled global economy gave stock markets the jitters, leading to falls in Europe and Asia, while trading on Wall Street was muted.
And oil prices fell sharply on fears the escalating outbreak could further dampen economic activity and impact energy demand.
Although the US government has declared a public health emergency with 44 cases in five states, President Barack Obama urged calm.
The swine flu outbreak “requires a heightened state of alert, but it is not a cause for alarm,” he told a gathering of the National Academy of Sciences.
Richard Besser, acting director of the US Centers for Disease Control and Prevention (CDC), said the affected states of New York, Ohio, Kansas, Texas and California and others were receiving 11 million courses of antiviral drugs.
Besser stressed that of so far most people in the US had only been mildly ill.
Swiss pharmaceutical group Roche said it was ready to send out more stocks of the antiviral medication Tamiflu, some 220 million doses of which are in the hands of governments worldwide.
And British pharmaceutical giant GlaxoSmithKline also said it was “urgently” investigating how to boost production of its antiviral drug Relenza, as the race to develop a direct vaccine for the H1N1 strain gathered pace.
The company has already provided 100,000 packs of the drug to Mexican authorities, along with a further 170,000 doses of its seasonal flu vaccine.
The European Union called emergency talks of health ministers and advised against non-essential travel to areas where the deadly virus has surfaced.
The United States issued a travel alert warning against “non-essential travel” to Mexico.
In New Zealand the government said it was investigating a further possible 56 cases of swine flu, while one person in Peru and up to 12 in Canada are under observation with flu symptoms.
There have been six confirmed cases in Canada and in the Middle East, a 26-year-old Israeli was also hospitalized.
AmericanHealthOptions.com reminds that top anti viral medication for flu treatment is Tamiflu.
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