Swimming with Seals riskier than Surfing with Sharks?

Seals  –  those cute, semi-aquatic marine mammals hunted for generations by humans may be about to wreak their revenge.  While we don’t want to get into the pros and cons of the cull, we would like to warn our readers of a new strain of flu found in New England harbor seals.

According to experts, seal flu could potentially threaten people as well as wildlife. In a report just published online in mBio, scientists from several organizations, including Columbia University and the National Oceanic and Atmospheric Administration suggest that seal flu could lead to another pandemic just as we saw with bird and swine flu.

“There is a concern that we have a new mammalian-transmissible virus to which humans haven’t been exposed yet. It’s a combination we haven’t seen in disease before,” said Anne Moscona MD, professor of pediatrics and of microbiology and immunology at Weill Cornell Medical College.

“A dangerous virus infecting mammals increases the risk to us – not by direct infection – but by evolutionary development of even more riskier strains,” explained Bruce Hirsch, an infectious disease specialist at North Shore University Hospital in Manhasset, N.Y.

Although transmission via direct contact between humans and harbor seals is unlikely, the virus could find other ways to get to people.  For example, the strain might pass from seals to birds, expand its presence in the environment.  And because seal flu is able to target a protein found in the human respiratory tract, it may have the potential to mutate in ways that make it easily passed to or between humans.

The researchers analyzed the DNA of a virus linked to the death of 162 harbor seals in 2011 off the coasts of Massachusetts, New Hampshire and Maine. Five autopsies revealed that the seals died from infection with a type of flu known as H3N8.

Because pandemic flu can originate in unexpected ways, preparation is essential. The Centers for Disease Control and prevention (CDC) offers some excellent tips on its website.

And we suggest for this year at least you might be better off diving with dolphins than swimming with seals!

 

 

 

Kicking Up A (cytokine) Storm

The New Year brings with it many new possibilities, including, unfortunately a new flu season.

So far, the number of flu cases in 2012 is down, thanks largely to the unprecedented mild weather over most of the US. A sharp contrast to 2009 when H1N1 (or swine flu) killed more than 18,000 people worldwide or 1918 when the flu virus infected around a third of the world’s population and killed at least 50 million people.

New research shows that the reason so many people died in both of those years wasn’t the influenza virus itself, but the immune system’s reaction to it.  It turns out that the virus destroys its host by turning the body’s own defenses against itself.

“While trying to destroy flu-infected cells, your immune system also destroys legions of perfectly healthy cells all over your body. This is why, even though the virus itself rarely ventures outside the lungs, the symptoms of the flu are so widespread” says , Michael Oldstone, a virologist at the Scripps Research Institute in La Jolla, Calif.

Most of the time this immune response isn’t too severe. As the virus runs its course, the response subsides. But in some cases, an infection can trigger a reaction so destructive it can be fatal. Scientists call this a cytokine storm, because of the violent way immune cells respond to a virus. Cytokines usually help fight off infections by telling the immune system which specific viral cells it should be attacking, but sometimes an overabundance of cytokines floods into a part of the body, and that’s when you get a storm.

Cytokine storms are rare, but they may be more common among younger people because they have stronger immune systems, and are more prone to overreactions. This may explain one of the more surprising outcomes of the 2009 swine flu: that it was deadlier among young people than it was among the elderly.

Cytokine storms can cause serious damage throughout the body, especially in the lungs, which is why most flu deaths are attributed to pneumonia.

After 5 years of research, Oldstone and his colleagues have identified a cell — they call S1P1 – that responds to cytokines. More importantly they’ve also figured out how to turn off that cell’s signals. This could pave the way for a new class of immune-reaction-blocking drugs that could provide protection against cytokine storms and be more effective than antiviral drugs.

Cytokine-blocking drugs could target the flu effects that cause the most damage to the body and would avoid the problems of virus mutation because they don’t affect the virus itself.

Still, it will probably be many years before those drugs reach your local pharmacy. Although preliminary experiments in mice have shown very promising results they still have to replicate these in ferrets, then primates and finally, humans.

Do you have any flu stories to share? SRxA’s Word on Health would love to hear from you.

Universal Flu Vaccine One Step Closer

For the millions of people around the world who suffer each winter from flu, and especially for those with weak immune systems, such as, children, the elderly and pregnant women there is promise of a new “super vaccine.”

Scientists from Switzerland’s Institute for Research in Biomedicine (IRB) just announced that they have isolated and identified a human antibody – F16 –  that can knock out all influenza A viruses. Tests in mice showed it was effective.   This represents an exciting step forward in the hunt for a universal vaccine.

Currently, in what amounts to little more than a scientific lottery, virologists have to play catch-up as they develop a new flu vaccine cocktail each season to match the often-changing strains of the virus.

F16, could help change all that. “The antibody works not only by neutralizing the virus, which we knew, but also by recruiting killer cells to the virus-infected cells,” said Antonio Lanzavecchia, director of IRB.

By observing the human immune response to the 2009 H1N1 flu pandemic he became convinced that it would be possible to design a vaccine that prevails over mutation.   “We found some people with antibodies to multiple viral sub-types.” Antibodies, which are produced by white blood cells, bind to specific target sites inactivating viruses or flagging them for destruction by other immune cells.  To test the cross-reactivity of influenza antibodies, the team screened B cells from eight human donors who had been infected with or immunized against different flu strains.  After looking at 104,000 B cells, they hit the jackpot!

“Our FI6 antibody is the first one ever found that reacts to all 16 of the influenza A subtypes,” said Lanzavecchia.

“Finding antibodies to all strains of one group was exciting,” says immunologist, Patrick Wilson from the University of Chicago, Illinois, who was not involved with the study, “but getting one to both groups is stunning.”

The F16 antibody is not a vaccine, but it could be an instruction manual for making one.  And although the scientists admit that making a new vaccine may take years, they hope that the antibody itself might be used as a treatment in the meantime. So far, tests in animals have shown that when the antibody binds to the virus, it stops it from infecting mammalian cells.

Once tested in a human system, the antibodies should work even better.  However, even reducing the viral load by 10% could help stop people getting sick.

SRxA’s Word on Health looks forward to having one less thing to worry about in winter.

Not so Rotten Eggs!

As someone who stood in line for 3 hours to receive my H1N1 vaccine last year, only to be turned away by an officious clipboard wielding nurse, this Word on Health blogger just had an “I told you so” moment!

According to new recommendations by the American Academy of Allergy, Asthma & Immunology (AAAAI), anyone with a history of suspected egg allergy should first be evaluated by an allergist or immunologist for appropriate testing and diagnosis but can probably receive the vaccination.

Matthew J. Greenhawt, M.D., and James T. Li, M.D., Ph.D., from the Department of Internal Medicine at Mayo Clinic, have co-authored the guidelines based on recent studies that show that even the most egg-allergic individuals can receive the flu vaccine safely under the care of their allergist/immunologist.

As I know only too well, in the past, people with egg allergy were told they could not have the flu vaccine because it contained egg protein which could potentially trigger an allergic reaction. However new research shows that not only do flu vaccines contain only tiny amounts of egg protein, the vast majority people with egg allergies don’t react.  Indeed it seems that many people with diagnosed or suspected egg allergy can receive the influenza vaccination successfully, if simple precautions are followed.

These include:

• Anyone with a history of suspected egg allergy should first be evaluated by an allergist or immunologist for appropriate testing and diagnosis
• Patients with a confirmed egg allergy can then receive the vaccine safely using one of two protocols: a two-step graded challenge or a single, age-appropriate dose

“It is not necessary to withhold influenza vaccination from egg-allergic patients,” says Greenhawt. “Our recommendations provide two flexible approaches to vaccination. Each approach is backed with recent evidence that it is safe. Most allergists should be able to identify with one of our recommended approaches and, as such, be able to vaccinate their egg-allergic patients with confidence.”

So, Nah! Nah! Na! Nah! Nah! to you officious nurse.  Who has egg on their face now?

Do you have vaccine stories to share?  Word on Health would like to hear them.

The end of swine flu?

Word on Health breathed a big sigh of relief earlier this week when the World Health Organization (WHO) declared the official end of the influenza A (H1N1) pandemic.

According to WHO the virus has largely run its course and we are now in the “post-pandemic period.” In other words, the virus is now expected to take on the behavior of the seasonal flu virus.

Does that mean we can expect to see few people wearing surgical masks in airplanes and on the Metro?  Will it be safe to leave our homes and desks without our bottles of hand sanitizer?

Can we revise our infectious disease presentations once again and consign H1N1 to the box of viruses of former concern, along with Ebola and SARS?

Was all the fuss worth it?

Responding to concerns that the agency acted too hastily in declaring a pandemic  last June, the WHO said it was “the right call.”  WHO Director-General Margaret Chan added that “we have been aided by pure good luck.” Chan noted,  if the virus had mutated then the current death toll of around 18 500 could have been much higher.

For those of you who can’t quite shake off the fear of H1N1, the good news is that the regular 2010 flu shot will contain protection against swine flu too.