Swine Flu vs. Bird Flu: Which Is the Greater Pandemic Threat?

As health officials around the globe continue to monitor the swine flu outbreaks that have occurred within the past month, comparisons with the periodic bird flu outbreaks over the past decade are difficult to avoid.

Specifically, some may find themselves asking the question: Since the bird flu failed to spark a full-blown pandemic, should we really worry about swine flu?

Infectious disease experts say there are numerous key differences between the two viruses and their pandemic potential, and a new study published on Friday in the journal PLoS Pathogens hints at just one of these differences. In the study, British and U.S. researchers revealed that the bird flu virus becomes impaired at 89.6 degrees Fahrenheit -- the temperature of the human nose -- therefore making it less likely that it can spread from person to person.

The human nose, in other words, may simply offer too cold a climate to encourage the spread of the avian flu virus. Whether this will always be the case is not yet known, but the researchers said that a substantial mutation would have to occur in the bird flu virus before it would become a pandemic threat for humans.

"Bird viruses are out there all the time, but they can only cause pandemics when they undergo certain changes," said Wendy Barclay of the Imperial College in London, one of the study's authors. "Our study gives vital clues about what kinds of changes would be needed in order for them to mutate and infect humans, potentially helping us to identify which viruses could lead to a pandemic."

The study may also provide scientists with the mechanisms of virus mutation in general, allowing them to predict which viruses are more likely to spread to humans.

Dr. William Schaffner, chair of the Department of Preventive Medicine at the Vanderbilt University School of Medicine in Nashville, Tenn., called the study "very nice work that adds another explanation why the bird flu is not being transmitted readily in people."

Swine Flu Beats Bird Flu in Human-to-Human Transmission

"Previously it has been shown that the avian influenza viruses did not attach to the cells of the upper respiratory tract, but could attach lower down," Schaffner said. "The current study provides an additional potential explanation."

Ed Hsu, associate professor of public health informatics at the University of Texas School of Health Information Sciences and School of Public Health, agreed. "This study renders potential explanations for why Avian Flu virus does not effectively transmit from human to human -- an important indicator for raising pandemic level."

But Dr. Pascal Imperato, dean of the Graduate Program in Public Health at SUNY Downstate Medical Center in Brooklyn, N.Y., warned that the fact that this was an in vitro study -- in other words, one that took place in a Petri dish -- meant that more research would be needed to determine whether the findings are an accurate reflection of what happens in humans.

"The findings would need to be corroborated in order to have credibility," Imperato said. "That said, there are many other variables that determine the infectivity of a pathogen. While these findings are of interest, they really do not alter our current understanding of the pathogenicity of influenza viruses."

Bird Flu vs. Swine Flu: Differences in Pandemic Potential?

As the human nose is a crucial site of infection for any flu bug, the new research might help explain why, even at the height of the bird flu scare, there was little evidence of human-to-human spread.

According to the World Health Organization website, since the bird flu virus re-emerged in 2003, there have been only 423 reported cases -- on average, about 60 cases per year worldwide.

Most avian flu cases occur after the victims had had close contact with live poultry. Few cases are currently suspected to have occurred through human-to-human contact, and in most cases the spread was successfully contained through the systematic destruction of bird populations.

The avian virus seems instead more suited for the balmy 104-degree conditions found in the gut of a bird. Exclusively human influenza viruses also do well under those conditions, but unlike the bird flu virus they are not as adversely affected when placed in colder temperatures.

Health Officials Still Warning of Swine Flu Threat

Viruses that are not affected by the colder temperatures are more likely to become a problem, the researchers said. The swine flu virus, for example, may be able to thrive in a wide range of temperatures, and that may explain its quicker spread. There have been 4,694 cases so far across 26 countries, including the U.S., Canada, Malaysia, and the U.K. Although the flu strain is mild, a more virulent mutation can prove to be devastating.

Take, for example, the virulence of bird flu. Despite the relative paucity of human cases of bird flu among humans, Hsu said, 258 people have died since 2003 as a result of the bird flu virus -- a case fatality rate of more than 60 percent.

"Once [bird flu] viruses get passed the proximal pathway, low temperature 'barrier,' they replicate so quickly that they often overpower the host and thereby cause high fatality," Hsu said.

And if the viruses were to somehow be able to bridge this barrier, there is a chance that they could become more problematic.

"As more people are exposed to the [bird flu] strains, it is possible that mutations may occur that lead to more efficient bird-to-human transmission," said Ella Nkhoma, a researcher and epidemiologist at the University of North Carolina at Chapel Hill. "However, whether such a mutated virus would maintain sufficient fitness to efficiently sustain human-to-human transmission is unclear. So far, human-to-human transmission has been very rare."

Indeed, infectious disease experts largely agree that the outbreaks at hand may warrant more worry than the bird flu.

"Many experts now think that, after 4-5 years, because the current H5N2 bird virus has not mutated into a human-transmissible strain, that it is unlikely to do so," Schaffner said. "At the moment, the H1N1 [swine flu] virus has a much greater potential for producing a pandemic."

This threat has not been lost on international health officials. On Friday, WHO cautioned against a false sense of security from the dwindling and seemingly mild outbreaks of swine flu, saying the worst may not be over for the newly-discovered virus.

WHO Director-General Margaret Chan said there remained "great uncertainty" about the strain that could pose particular threats in Southeast Asia.
Read More...

NYC Students, Staffer Ill With Swine Flu

New York City has closed three schools in response to a swine flu outbreak that has left one staff member in critical condition and sent hundreds of kids home with flu symptoms, in a flare-up of the deadly virus that sent shock waves through the world last month.

A Health Department spokeswoman tells The Associated Press that four students and the staff member have tested positive for swine flu at a middle school in Queens. At another middle school in Queens, 241 students were absent Thursday. Dozens more were sick at an elementary school.

Mayor Michael Bloomberg scheduled an evening news conference to discuss the outbreak.

New York City's first known cases of swine flu appeared in late April, when hundreds of teenagers at a Roman Catholic high school in Queens began falling ill following the return of several students from vacations in Mexico, where the outbreak began.

At first the virus appeared to be moving at breakneck speed. An estimated 1,000 students, their relatives and staff at the St. Francis Preparatory School fell ill in a matter of days.

City health officials became aware of the outbreak April 24. The school closed and health officials began bracing for more illnesses throughout the city.

But the outbreak then seemed to subside. Additional sporadic cases continued to be diagnosed, but the symptoms were nearly all mild. The sick children recovered in short order, and St. Francis reopened after being closed for a week.

Health officials in New York and elsewhere said that the virus, at least in the U.S., appeared to pack no more serious a punch than the seasonal influenza viruses that arrive each winter.
Read More...

Swine Flu: Top 5 Reasons Not to Panic

Doctors battling swine flu must walk a tightrope between informing the world so people can protect themselves, and sending people to the hospitals with an anxiety attacks instead of the flu.

But as reports of a few cases in California and Texas on Friday turned into hundreds and the World Health Organization issuing a pandemic threat level of 4 on Monday -- some otherwise healthy people feel on edge.

"I'm pretty much freaking out," said Brandon Syms, a freshman at Boston University who just received an e-mail from the school detailing the spread of swine flu. "I've gotten a cold or something a few days ago. I've been coughing a lot, and I've been getting a sore throat."

Syms, who claims he normally isn't a "germaphobe," said he's been obsessing about the possibility of his cold being swine flu for the past 24 hours -- yet he said he's too afraid to go to the doctor and hear the bad news if he does have it.

"I wonder if there are a whole lot of people who don't want to find out and they have it and they're spreading it around," said Syms. "Now I'm thinking about it all day long."

To make matters worse, he can't stop biting his fingernails so he's worried he's putting the virus in his mouth at every turn.

"It makes me nervous," he said. "What would calm me down right now, other than my mom, would be if they would talk more specifically about what this is, how it affects the body."

Despite the rising threat, and the rising numbers, many public health experts say they aren't too worried for now.

The following are doctors' top reasons why the public shouldn't panic about the swine flu -- yet.

Reason 1: The Low Numbers… For Now

"It's just a handful of cases. It is spreading but it's still quite early," said Dr. Martin Blaser, chairman of the Department of Medicine at New York University Langone Medical Center in New York City.

"In most cases, it's just regular influenza -- it's something that happens every year all the time," he said.

Although he expects the numbers to rise this week as labs catch up to diagnose current cases, Blaser said the public should bear in mind their own strength in numbers.

On Monday the CDC reported 42 confirmed cases in the United States, a country with more than 300 million uninfected people.

Those numbers are exactly why Steve Catoe, a blogger with a congenital heart problem, has decided he's going to put his worry on the back burner for now.

"From what I understand that's just really odds now," said Catoe. "It may be panic-worthy now, but I'm just too dumb to realize it."

Catoe has always had to worry more about infections than the average person. Tricuspid atresia, meaning he is missing one of the connective valves in his heart, has left Catoe's blood oxygen level so low that his fingertips are perpetually blue.

"I'm up close and personal with what can happen if you don't take care of yourself," said Catoe, who has lingered in the hospital for a whole summer with infections that most people could overcome in a week or two. Simple colds can knock him out and give him insomnia for days.

"I am a vulnerable person and swine flu needs to be kept an eye on, but it's not something I'm going to change my lifestyle for," said Catoe.

Reason 2: How Deadly Swine Flu May Be….

Doctors worry most about people like Catoe, children and the elderly and others with weak immune systems during a flu outbreak.

While that still holds true with swine flu, those who study outbreaks say that A(H1N1) isn't the deadliest strain out there.

"A thing to keep in mind is the case-fatality," said Ed Hsu an associate professor of Public Health Informatics at the University of Texas School of Health Information Sciences in Houston.

Case-fatality is a simple way to measure how deadly a disease can be: the percentage of people who got the disease and did not survive. Hsu said case fatality for severe acute respiratory syndrome (SARS) reached more than 15 percent, while bird flu reached 60 percent.

"What we're seeing in Mexico case fatality is about 10 percent, and some of those are not confirmed," said Hsu. "Compared to bird flu it's relatively mild."

s of Tuesday evening, Mexican Health Officials report they have 20 confirmed deaths from the swine flu virus, while the World Health Organization says their current laboratory-confirmed total is seven.

Reason 3: Swine Flu Meet Tamiflu… For Now

Although doctors don't have a vaccine for the new strain of swine flu, Blaser said there is hope in our medical arsenal.

"At this point the strain is sensitive to flu medication such as tamiflu," said Baser, who is also the past president of the Infectious Diseases Society of America.

Tamiflu can subdue many flu infections if taken within 48 hours of the first symptoms. The current federal Public Health Emergency declaration has allowed the federal government's to stockpile and allocate flu medication to areas that need it most.

But Blaser warns people not to take flu medication without a prescription -- especially if they have not had any symptoms.

"If enough people do, the virus will become resistant and it [the medicine] will not work," said Blaser.

Although mommy-blogger Amy Anaruk, author of theasthmamom.com, hasn't run out to get Tamiflu, she did get children's acetaminophen, found doctors for her family just in case, and then spent the better half the weekend calming down.

"I've gotten to the point of feeling sane about it -- you just can't live your life that way," said Anaruk. "When you see health officials who say 'prepare, prepare, prepare,' you start to think that it's inevitable -- especially if you have child with a chronic health problem."

Certainly declarations of public health emergencies have led such worries, but experts say it's a sign that governments are better prepared for pandemics than ever before.

Reason 4: Governments, Scientists Have Learned their lessons

"In terms of quarantine and travel rules -- we are much better prepared," said Hsu. "This is a great, great, improvement and this is a lesson learned from previous outbreaks."

Although it scares most people that swine flu cases are popping up all over the globe, to Hsu it shows governments aren't trying to cover up a disease.

"It is a good sign, which is the transparency of reporting," said Hsu.

Blaser concurred on the government's responsiveness -- not only with the speed at which they declared a public health emergency but with the money and work put behind finding a new vaccine.

"Work on developing a vaccine for this flu is already underway," said Blaser. "The Centers for Disease Control, the federal government, the World Health Organization --- they all have this on their radar screen, which is good."

Reason 5: Watch Out Flu, It's Springtime

As the numbers of swine flu cases climb, Hsu said he and his colleagues are keeping a close eye on the disease trends.

Based on his past work with the bird flu and SARS, Hsu said most infections decline in the summer months. If swine flu follows suit, then there are good signs a pandemic has been avoided.

"Looking at the trend, the flu data the flu trend should be declining in May," said Hsu. "The next few weeks should be important."
Read More...

Tourism Hit by Swine Flu: U.S. Warns on Mexico Travel

The U.S. is issuing an advisory urging Americans to avoid "unnecessary travel" to Mexico, where as many as 149 people have died of swine flu.

There are roughly 4,000 flights per week between the U.S. and Mexico. The Centers for Disease Control and Prevention is issuing the advisory "out of an abundance of caution," acting CDC chief Richard Besser said at a press conference today.

The European Union's health commissioner, meanwhile, appears to have irked U.S. officials by warning Europeans to avoid nonessential travel to both Mexico and the United States.

Besser called the U.S. travel warning "premature." He said that while 40 swine flu cases have been identified in the United States, there has been only one hospitalization for the disease.

There are 28 confirmed cases of swine flu in New York City, but Mayor Michael Bloomberg said the outbreak shouldn't dissuade tourists from visiting the city.
U.S. Airlines Take Action on Swine Flu

U.S. airlines are also taking action. American Airlines said Sunday that anyone who bought a ticket to Mexico before April 25 for travel to or from Mexico won't incur a penalty for changing reservations. The waiver is in effect through May 6.

United Airlines announced a similar waiver, saying that passengers who bought tickets on or before April 26 for travel through April 30 may change their tickets without having to pay a penalty.

Swine Flu Rattles Stock Markets

Fears about the impact of swine flu on tourism and travel sent airline stocks in Asia down sharply.

Stocks soared for pharmaceutical companies Roche Holding AG, of Switzerland, and Britain's GlaxoSmithKline as governments and corporations boosted their orders for their flu drugs, Tamiflu and Relenza.
Read More...

Swine Flu: What You Need to Know

As U.S. officials warn of the spread in swine flu cases across the country, there are a number of steps Americans can take to protect themselves and their children from this unique virus.

The rapidly spreading swine flu is a new virus that includes combination of swine, bird and human strains. It has taken the lives of 81 people in Mexico, and sickened more than a thousand south of the border.

In the United States, 20 cases have been confirmed thus far -- seven in California, two in Kansas, eight in New York City, one in Ohio and two in Texas.

Simple preventive measures, such as washing hands frequently and avoiding people who are coughing or sneezing, can go a long way toward keeping Americans safe from the virus, which health officials expect is likely to afflict more people.

"There is a role for everyone to play when an outbreak is going on to try and reduce the impact," said Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention (CDC). "At an individual level, it's important people understand how they can prevent respiratory infection. Frequent handwashing [is an] effective way to reduce transmission of diseases."

The World Health Organization declared the unusual virus a "public health emergency of international concern," but fell short of calling it a pandemic.

What is a Pandemic?

A flu virus can reach pandemic status if three conditions are met, according to the World Health Organization.

First, it must be an infection that has newly emerged. Secondly, it has to be able to cause serious illness in humans. And thirdly, it must be able to spread easily from person to person. Infections in this category can often spread beyond their continents of origin -- and potentially around the world.

When a flu virus mutates in such a way that it forms a novel version, it means people typically have little to no protection, because their immune systems have no experience fighting that form of the virus. Flu viruses can spread quickly and potentially cause more severe illness when the population lacks immunity.

Scientists around the globe are working hard to determine the threat level of the current swine virus. Right now, the virus is said to have "pandemic potential" because it is a new virus that can spread from person-to-person.

But if it turns out the virus does not spread easily among people, the threat level will go down. Similarly, if it turns out the virus can spread easily among people, the threat becomes more serious and the virus is more likely to trigger a pandemic.

"The distinction about a pandemic is that you need a distinct virus that human population hasn't seen before. Once it starts to spread, it moves rapidly from country to country and from continent to continent and we don't have that yet," said Dr. William Schaffner, chairman of Preventive Medicine at Vanderbilt University Medical Center in Nashville, Tenn.

He added that it is still too early to use the "P" word just yet.

"I'm still observing this as a variant of seasonal influenza. I don't know if we've seen that kind of [global] spread yet so I'm a little bit cautious. However it's in everyone's mind," he said.

But all pandemics are not equally deadly. Some kill millions more people than normal flu outbreaks, while others are roughly on par with seasonal flu in terms of deaths.

It is not possible to predict a pandemic in advance, so health officials keep a close watch on viruses that have "pandemic potential" -- new viruses that have shown at least some ability to transmit to humans.

The current H5N1 bird flu circulating in Asia is an example of a virus that has pandemic potential, but has not yet caused a pandemic.

Pandemics can vary quite a bit in severity. The 1918 pandemic killed many more Americans than an ordinary flu, while the 1968 version killed about 34,000 people -- about the same number killed each year by seasonal flu, according to CDC statistics.

The world generally experiences at least two flu pandemics each century.

What Does a Public Health Emergency Entail?

Declaring a public health emergency allows states to free up their resources for prevention of the disease in question.

That declaration gives the head of the Department of Health and Human Services authority to take rapid measures -- including authorizing contacts and mobilizing the national disaster system -- to respond to the disease, including allowing the use of unapproved drugs.

Scientists have not yet determined the reason why there are reported swine flu deaths in Mexico while cases in the United States have thus far been mild.

The WHO noted that the U.S. cases have all been confirmed by laboratory analysis, while those in Mexico have not all been confirmed as yet. This means that health officials do not know how many people who died in Mexico perished because of the new swine flu virus.

However, the CDC is concerned that because the virus is genetically similar in the United States and Mexico, the United States will see more severe illness as new cases emerge, including some deaths.

What You Need to Know About Swine Flu

What many people do not realize is that the flu is generally a much more serious illness than most people appreciate. Even the "typical" flu season results in 36,000 American deaths each year, according to CDC statistics.

The swine flu is a type of influenza virus usually found in pigs. The most common version is H1N1, and the current virus causing concern is a new variation of that virus. Swine flu does not typically pass to humans directly, but such transmission can occur. The current swine flu virus concerns health experts because it has shown the ability to pass from human to human.

When a person gets the swine flu virus, it takes 48 hours before the infected person actually begins to feel ill.

"It takes time for the virus to get down and start to create an illness. That interval between exposure and onset of illness is called the incubation period. The virus hasn't manigested itself," Schaffner said.

Once a person becomes ill, they can stay that way for anywhere from 48 hours to seven days. So far, in the United States, the cases of swine flu have been mild.

There is no vaccination for the swine flu system. U.S. and WHO officials said they are beginning work on a vaccine, but that could take months to develop.

Two prescription anti-viral drugs -- Tamiflu and Relenza -- have proved effective in combating the swine flu virus in victims in the United States. The Obama administration has released 12.5 million courses of the country's stockpile of 50 million courses of Tamiflu.

Health officials and doctors don't recommend people go to the hospital if they are experiencing flu-like symptoms. Rather, they should contact their doctor.

Doctors recommend getting rest and drinking plenty of fluids, and using Tylenol and Advil, which have proven effective for flu symptoms.

Doctors recommend "self-quarantine" for those inflicted with the influenza, so that it does not spread to others. If children are sick, they should not be sent to school. For adults, they should stay away from their workplaces and maintain as much distance as possible from others. Travel on buses or airplanes is not recommended.

Doctors say it is only natural for flus to spread in places like schools, where there is a lot of interaction.

It is hard to distinguish the symptoms of a swine flu from any other flu.

Schaffner said the one distinction is that the swine flu is not a common cold.

"Common cold has its symtoms from the neck up -- sore throat, stuffy nose and feeling crummy. However influenza tends to make you feel much more ill. You can have a sore throat but then you also get cough and muscle aches and pains," he said.

The Swine Flu Symptoms

Hayden Henshaw, an 18year-old from Cibolo, Texas, who was diagnosed with the swine flu last week, said he felt regular flu symptoms.

"You just get really run down, my skin and my muscles were achy. I had a cough and slightly feverish." he told ABC News.

His father, Patrick and 11-year-old sister, Hannah, also got the flu from him.

"It's just like any other flu but the vaccine doesn't help with this strain," his mother, Robin, told ABC News.

Doctors recommend looking out for symptoms such as a fever of more than 100 degrees, body aches, coughing, a sore throat, respiratory congestion and, in some cases, vomiting and diarrhea.

In the absence of symptoms, officials say people don't have to get tested. If they are experiecing the symptoms, they you should take precaution and stay away from others.

The WHO is developing a profile of the "typical case" of swine flu, but thus far, the symptoms appear to be essentially the same as those for the usual winter flu. The only way to definitively diagnose swine flu is to have laboratory testing done to determine the exact subtype of the virus.

Swine Flu Is Called a Global Threat

The WHO has a six-phase approach for dealing with large outbreaks of viruses. The six threat levels help the organization determine the course of action it needs to take and the kind of guidelines and recommendations it needs to provide to countries.

Phase 1 means no viruses circulating among animals are reported to have caused infections in humans. The Phase 2 threat is activated when the virus has spread from animals to humans and has "potential pandemic threat."

The threat level is escalated to Phase 3 -- such as after the swine flu spread -- when the virus is reported in clusters, but has not resulted in enough human-to-human transmission to have caused a large outbreak at the community level.

Phase 4 means the virus has resulted in "community-level" outbreaks, and is at a strong risk of becoming a pandemic.

Phases 5 and 6 mean there is widespread human infection, and the uptick to Phase 5 means that a global pandemic is on its way. Phase 6 is post-peak, meaning the virus has dropped from its most sever but hasn't completely disappeared.

In the post-pandemic period, influenza disease activity will have returned to levels normally seen for seasonal influenza.

Currently, the WHO has a threat level of 3 but is considering raising it to 4. WHO officials said they are not yet convinced that this is a pandemic and there are still a lot of questions about the strength and lethality of the swine flu virus.

7 Ways to Protect Yourself

"[Prevention is] no different than any other pandemic flu, and those are kind of simple things -- wash your hands a lot, don't shake hands or hug or kiss people if you're sick, don't go to work, self-qurantine yourself," said Peter Katona, an associate professor at the University of California, Los Angeles (UCLA) Medical Center.

1. Wash hands frequently: This will lessen the chance of carrying or transmitting any viruses that normally get stuck on the hands in day-to-day activities. Try to avoid rubbing eyes or touching nose with dirty hands. Wash hands often with soap and water, especially after coughing or sneezing. Alcohol-based hand cleaners are also effective.

2. Try to avoid people who are coughing and sneezing: The CDC advises people to cover their nose and mouth with a tissue when they cough or sneeze and throw the tissue in the trash after using it. Try to teach your kids to do the same. Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.

3. If experiencing flu-like symptoms, don't go out -- stay at home. Call a healthcare provider, particularly if a person has been to Mexico, southern California and southern Texas. The CDC recommends that people who get sick stay home from work or school and limit contact with others to keep from infecting them.

4. Taking a trip to Mexico? Rethink your plans. Schaffner said that unless you have a compelling reason to go, you might want to reconsider. Many airlines, including Continental, US Airways and American Airlines, are waiving cancellation fees on tickets to Mexico.

5. Stay informed and plan ahead: Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said it's important to stay informed about what's going on in one's community, and whether the authorities -- such as the state or county health departments -- have issued any recommendations. It's a good idea to plan for what to do if children's school is closed.

6. Keep sick kids out of school, and stay home from work if you are sick. Aside from providing needed rest, such absences protect others from catching whatever you or your kid has. Keep at least a few feet's distance if you have the flu or are interacting with someone who has the flu. The communicable distance for most flu viruses is about three feet, so keep clear of this radius in order to avoid spread. If dealing with a flu case at home, make sure the flu sufferer (and even those who interact with this person) wear facial masks to lower the chances of spread.

7. Avoid surfaces and objects that may be handled by many people. For kids, this may include doctor's office toys, surfaces that a lot of other kids are touching. Keep all surfaces and objects around the house clean. This becomes especially relevant if there is someone in that house who is sick or has the flu already. Try to teach kids not to touch their faces. This is like mass transit for germs: straight from the hands to the eyes, nose and mouth.

The CDC advises those who feel symptoms to contact their doctor right away. And finally, one myth that can be dispelled: There are no signs that people can get the swine flu from eating pork.
Read More...