In the first confirmed case of drug-resistant swine flu worldwide, a Danish patient developed resistance to Tamiflu, the antiviral treatment used for flu prevention and treatment. The patient recovered and did not appear to have passed the resistant strain to others. While a drug-resistant virus could make it harder to treat and prevent the spread of the flu, experts maintain that the isolated case is not a cause for alarm, and say Tamiflu is still effective against the swine flu.
A spokesman for Tamiflu manufacturer Roche says the Danish patient developed drug-resistant swine flu while taking the drug as a preventative to avoid the contraction of swine flu…. He was probably already infected with the virus, and resistance to the drug emerged because he was given the lower preventative dose [The Wall Street Journal]. This type of resistance is known as drug-induced resistance, as opposed to naturally occurring resistance, in which a strain itself mutates to become unresponsive to a medication.
The U.S. Centers for Disease Control and Prevention continues to recommend Tamiflu to treat the flu, along with another flu drug, Relenza. The World Health Organization also is expected to keep supporting the use of Tamiflu. Tamiflu-resistant strains of the seasonal flu have been found in Japan, which has used more than half the world’s supply of the drug each year. But those strains were weak and did not spread. A Tamiflu-resistant strain of the H5N1 bird flu was also isolated from a Vietnamese patient being treated with low-dose Tamiflu in 2005, but it also died out [The New York Times].
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Seasonal flu outbreaks typically taper off in the warm and humid summer months, as the influenza virus can’t survive as long in those conditions as it does in the cold, dry air of winter. But the current outbreak of the H1N1 swine flu virus is quite different than a typical flu season, and may produce a very different pattern of infection: It may produce an extended year-round flu season that disproportionately hits young people, health officials said on Thursday…. “The fact that we are seeing ongoing transmission now indicates that we are seeing something different” [Reuters], said Daniel Jernigan of the Centers for Disease Control and Prevention.
The swine flu outbreak, which the World Health Organization officially declared a pandemic last week, has continued to spread around the world, although its fatality rate remains fairly low. Health officials estimate that at least 100,000 people in the United States have been infected, 1,600 people have been hospitalized, and 44 have died. In another difference from typical seasonal flu outbreaks, the swine flu has disproportionately infected young, healthy people. Jernigan says its likely that older people have been exposed to a similar virus to the H1N1 virus at some point, which gives them some immune response to the current virus, while children are believed to have a “complete lack of immunity to this particular virus” [Reuters], he said.
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The World Health Organization is expected to officially classify the ongoing H1N1 swine flu outbreak as a pandemic in the next couple of days, but health officials are taking pains to stress that the “pandemic” label only indicates that the virus is spreading through communities in more than one region of the globe–it does not mean that the virus is killing everyone in its path.
WHO official Keiji Fukuda explains: “It does not mean that the severity of the situation has increased or that people are getting seriously sick at higher numbers or higher rates than they are right now…. One of the critical issues is that we do not want people to ‘over-panic’ if they hear that we are in a pandemic situation” [Reuters].
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While initial public panic about the swine flu outbreak has largely subsided, the virus continues to spread through our species: The World Health Organization has tallied more than 10,000 cases worldwide, with 80 deaths confirmed. As patterns begin to emerge regarding who gets infected with the H1N1 flu virus, health officials are beginning to map out strategies for a potential wide-spread vaccination campaign.
Young people are particularly prone to infection, researchers say. Preliminary studies of family transmission showed that when one member gets infected, the most likely to follow are those under 18, not parents or grandparents [The New York Times]. The virus’s spread through the young has led to the closing of schools in infection hotspots–Japan is the most recent country to shut school doors–but most cases in young people have not been severe. The people who do get more serious cases that lead to hospitalization have tended to have underlying health conditions like heart problems, lung ailments, immune diseases, and diabetes. Surprisingly, obesity has also emerged as a risk factor.
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The swine flu virus that has infected almost 6,500 people in 33 countries is not the product of a lab accident, World Health Organization officials declared yesterday.
The health officials were arguing against a hypothesis that emerged earlier this week. An Australian researcher named Adrian Gibbs who was has been involved in the development of antiviral flu drugs issued a report suggesting the new strain may have accidentally evolved in eggs scientists use to grow viruses and drugmakers use to make vaccines. Gibbs said he came to his conclusion as part of an effort to trace the virus’s origins by analyzing its genetic blueprint. “One of the simplest explanations is that it’s a laboratory escape,” Gibbs said…. “But there are lots of others” [Bloomberg]. Gibbs said this new virus had evolved faster than other flu viruses found in pigs, which he said suggested that it combined with other viruses being used in a lab. He argued that the virus could have then escaped into the general population.
But at a press conference, WHO official Keiji Fukuda announced that the hypothesis had been investigated and rejected. “Based on that evaluation by all of the laboratories, the conclusion is that this group of scientists feels that the hypothesis does not really stand up to scrutiny,” Dr. Fukuda said. “The evidence suggests that this is a naturally occurring virus and not a laboratory-derived virus” [MedScape]. He did not go into specifics of the investigation, but did say that the virus’s mutation rate was typical.
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A “fast and dirty” analysis of the spread of swine flu thus far has led researchers to believe that the virus will eventually turn into a true pandemic infecting about a third of the world’s population–but they hasten to add that the analysis also suggests that the flu doesn’t have a devastating death rate.
Lead researcher Neil Ferguson, a member of the World Health Organization’s emergency committee for the outbreak, says: “This virus really does have full pandemic potential. It is likely to spread around the world in the next six to nine months and when it does so it will affect about one-third of the world’s population. To put that into context, normal seasonal flu every year probably affects around 10% of the world’s population every year, so we are heading for a flu season which is perhaps three times worse than usual” [BBC News].
The analysis, published in Science, also roughly estimates that the flu has a fatality rate of .4 percent, meaning that it kills 4 people out of every 1,000 infected. That makes the swine flu virus about as dangerous as the virus behind a 1957 pandemic that killed 2 million people worldwide. But it’s not nearly as lethal as the bug that caused the 1918 Spanish flu pandemic [ScienceNOW Daily News]. Seasonal flu has a fatality rate of less than .1 percent, and kills more than 250,000 people each year.
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In an ironic twist to the swine flu epidemic, an infected farm worker has infected a Canadian herd of pigs with the virus, and the development is a bad public relations blow for the pork industry. The outbreak came on an isolated Alberta farm after a farm worker returned from Mexico on April 12 and had contact with pigs on the farm two days later. On April 24, pigs began showing signs of influenza; about 220 of the 2,200 pigs on the farm were found to be infected with H1N1 [The Globe and Mail]. The farm remains quarantined although the human and all the pigs have recovered from the flu.
World Health Officials note that the virus hasn’t yet been found in other pigs, including any pigs in Mexico–although epidemiologists are testing pigs in the towns where the flu first emerged in humans. The WHO has also begun calling the virus by its scientific name, H1N1, to avoid confusing consumers (the virus is passing from human to human with sneezes and coughs, like a seasonal flu virus). There is no risk of contracting influenza from pork products. Flu viruses are fragile: They can survive only hours outside a live body – human or animal – and are easily destroyed in meat by cooking [The Globe and Mail].
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With nearly 1,000 confirmed cases of swine flu reported around the world, World Health Organization officials say that the virus will probably continue to spread. However, they add that as of yet, there are few indications that it will cause any more trouble than a seasonal flu virus. WHO spokesman Gregory Hartl noted yesterday that the public may misunderstand the word “pandemic.” The term refers to where an illness spreads, not its severity [Washington Post]. Early genetic analyses of the virus suggest that it’s less lethal than originally feared, although researchers stress that the virus will continue to mutate and evolve.
The world has 985 confirmed cases of the virus, known to scientists H1N1 virus, in a total of 20 countries, WHO said Monday. The United States has reported 226 confirmed cases in 30 states. The U.S. cases include one death — a Mexican toddler visiting relatives in the United States [CNN]. A few isolated cases in Asia have triggered a draconian reaction from Chinese health officials, including the quarantine of Mexican travelers visiting China. But in Mexico, the center of the epidemic, Health Minister José Angel Cordova suggested that the outbreak may have passed its peak. “The evolution of the epidemic is now in its phase of descent,” he said [Financial Times]. Officials there will consider reopening schools and resuming public services this week.
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One week ago the world suddenly took note of swine flu, as a growing death toll in Mexico and the first rumors of cases in other countries raised the possibility of a pandemic. Now, after a fearful week of public paranoia and near hysterical reactions from some governments, researchers have taken their first hard look at the genetics of the virus. While the Centers for Disease Control still says it’s premature to say anything about the virulence compared with other strains of influenza based on genetic analysis [Technology Review], some researchers are arguing that the virus may be no more dangerous than the seasonal flu that hits every winter. But at this point, it is impossible to predict with any accuracy how the virus will continue to evolve [BBC News].
The H1N1 virus that is currently infecting humans is a blend of two viruses, a Eurasian swine flu and a North American swine flu, explains Raul Rabadan, a researcher who has analyzed the new virus. Influenza viruses mutate constantly and they also swap genetic material with one another promiscuously, especially if an animal or person is infected with two strains at once. Rabadan’s team said this particular strain looked partly like another hybrid, or what scientists call a reassortant, virus [Reuters]. The North American virus appears to contain genes from human and bird flu viruses as well, left over from previous genetic shufflings.
Flu researcher Wendy Barclay, who has also studied the virus’s genetic makeup, says that what she has seen thus far raises few red flags. When a flu virus binds to the upper respiratory tract, it tends to cause mild illness but can be easily spread as people cough and sneeze, Professor Barclay explains. If a virus binds further down in the lungs, it tends to cause much more severe illness, as in the case of the H5N1 avian flu virus which has caused concern in recent years [BBC News]. This swine flu virus appears to bind to the upper respiratory tract, Barclay says.
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In response to the continued spread of swine flu, which is now going by the more technical name H1N1, the World Health Organization raised its pandemic alert level from 4 to 5 yesterday, indicating that the virus is being spread between humans in at least two countries and that a global epidemic is imminent. Health officials stressed that now is the time for all countries to activate their pandemic preparedness plans, and to focus on mitigation strategies–namely, increased surveillance, early treatment for patients, and infection control in all health facilities.
“Containment is no longer a feasible option,” Dr. Keiji Fukuda, deputy director general of the World Health Organization, announced Monday night in Geneva after a meeting of the agency’s emergency committee on the spreading swine flu virus. “The world should focus on mitigation. We recommend not closing borders or restricting travel” [The New York Times]. In more recent comments addressing the U.S. decision not to close the border with Mexico, President Obama argued that such a move would be “akin to closing the barn door after the horse is out.”
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A 23-month-old Mexico child who was staying with relatives in Texas has become the first casualty of swine flu within U.S. borders, the Centers for Disease Control and Prevention announced today. “I can confirm the very sad news out of Texas that a child has died of the H1N1 virus,” the CDC’s Dr. Richard Besser said [CNN], although officials later added that the child had preexisting health problems. California is also investigating whether a man died from the viral infection. There are now 71 confirmed cases of swine flu in the United States, the CDC reports, and new cases are being investigated across the country, from Los Angeles to Chicago to Orlando, Florida.
At the epicenter of the outbreak, Mexico, 159 people have died and at least 1,600 people have been sickened by the flu. But although the virus has been spread by air travelers to other countries, only a handful of patients in the United States and elsewhere outside Mexico have been hospitalized, and severe complications have been relatively rare. “We still do not have a good explanation for why the pattern of cases in other countries appear relatively mild while the pattern of cases in Mexico appear to be much more severe,” said Keiji Fukuda of the World Health Organization [Washington Post].
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As the swine flu outbreak continues to spread, with Russia, South Korea, and Australia joining the list of countries with suspected cases and the death toll climbing in Mexico, attention has turned to the potential of a swine flu vaccine that could protect populations from infection. But a new vaccine takes some months to develop. Says Iain Stephenson, an expert on flu vaccines: “We are in a position where if a swine flu virus becomes a pandemic we don’t currently have a vaccine for it…. I think that it is unlikely there will be widespread vaccine in less than six to eight months” [Telegraph]. In the meantime, says Stephenson, patients can be treated with antiviral drugs.
International health officials haven’t yet decided whether the swine flu poses a serious worldwide threat that would call for the immediate prioritizing of a vaccine. The pharmaceutical company Novartis said it had received the genetic code of the new virus strain, enabling it to start work on evaluating production, and it hoped to receive the actual virus in its laboratories “in the near future.” … But the World Health Organisation (WHO) said it would only call for large-scale production of such a pandemic vaccine if it strongly believed the world was on the edge of an unstoppable global outbreak of flu [Reuters]. Vaccine companies are currently producing the seasonal flu vaccine, and health officials worry that calling them off that task could lead to shortages of the common flu shot.
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The swine flu outbreak that began in Mexico over the past few weeks has gone global, spread to new continents by infected air travelers returning from Mexico. Confirmed cases have been reported in the United States, Canada, and Spain, while suspected cases are being investigated in France, the United Kingdom, Brazil, Israel, and New Zealand. Amid fears that a global pandemic is in the offing, governments around the world are taking new precautions. Singapore, Thailand, Japan, Indonesia, and the Philippines dusted off thermal scanners used during the 2003 SARS crisis and were checking for signs of fever among passengers arriving at airports from North America [AP].
The situation remains worst in Mexico City, where many schools and public buildings are closed and doctors have warned citizens to wear face masks and avoid crowds. The virus is believed to have killed 103 people in Mexico, and sickened at least 1,600. But so far, the cases reported elsewhere in the world haven’t been as deadly.
A 23-year-old Spanish man has tested positive for swine flu, and at least 17 further suspected cases are under investigation in Spain…. The patients concerned had all recently returned from Mexico. None of the cases is thought to be life threatening [BBC News]. There are now 20 confirmed cases in the United States, including eight associated with a New York City elementary school where some students had recently been to Mexico for spring break. While the United States has declared the outbreak a public health emergency, health officials note that all the U.S. cases thus far have been mild, with no deaths reported.
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Mexico City health officials took the drastic step today of closing schools, from kindergartens to universities, in an effort to control an outbreak of swine flu that has killed at least 16 people in the last few weeks. It was clear that Mexican health officials were alarmed. Besides shutting classes, the government urged people to avoid large gatherings and to refrain from the common greetings of a hand shake or kiss on the cheek. City buses continued to operate but some passengers were seen wearing masks, and a cough or a sneeze by one passenger prompted others to relocate [The New York Times].
Experts say that the swine flu virus, which usually infects just a few humans who are in direct contact with pigs, has mutated into a more dangerous form that can be passed between people, and fear that it could cause a pandemic.
Meanwhile, officials are scrambling to understand how the deadly Mexican virus is related to an apparently weaker strain circulating in the American Southwest, which is not known to have caused any deaths. The first two cases in the United States were reported on Tuesday in Southern California. There are now five cases in California, including the father of one of the original patients. The other two cases are near San Antonio, Texas…. “We believe at this point that human-to-human spreading is occurring” [ABC News], says Anne Schuchat of the Centers for Disease Control and Prevention. However, she stressed that the U.S. virus does not currently appear to be a cause for serious concern.
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Egyptian health officials have just reported two deaths from bird flu within days of each other. The dangerous virus variant H5N1 struck down a six-year-old boy and a young woman, bringing the total death toll in Egypt to 25. While bird flu experts note that Egypt has seen a surge in human cases in recent months, with 16 confirmed since the start of the year, compared to seven cases between January 1 and April 17 last year [Reuters], they also say that the Egyptian people’s level of alarm is out of proportion to the threat.
Rumors have appeared in the Egyptian media that the virus is circulating widely, and that some people get “silent infections” which show no symptoms, but still allow them to pass on the virus. The rumors have been fueled by the pattern of recent infections: Many of the infected patients have been toddlers, leading to the belief that stronger adults are also infected but simply show no symptoms. Although thousands of Egyptians have rushed their children to hospitals this flu season, there is no evidence yet of asymptomatic avian flu cases or any significant mutation in the H5N1 virus. “Right now, it’s all hot air,” said Dr. Robert G. Webster, a flu expert…. “I hope to hell it’s not happening, because it would mean the virus is adapting to humans. But there’s not a shred of data” [The New York Times].
While the H5N1 virus rarely infects people, the looming fear is that the virus may mutate into a form that can be transmitted easily from person to person, which could spark a deadly pandemic. However, an outbreak of swine flu across the world from Egypt, in Southern California, has reminded people of the hazards of overreacting before all the information is in.
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