When 162 New England harbor seals died last year, it was sad. When scientists found that they died from an avian H3N8 influenza A virus, it immediately became a reason for serious concern. This virus is similar to the one already circulating in North American waterfowl, but this new type shows mutations that allow it to adapt to mammalian hosts – seals. A jump from seals to humans is not a giant leap, as we learned the hard way since the last bird flu. Is this new version of the deadly flu virus a sign of a new epidemic coming? It is too early to say, but scientists are cautious for a reason.
Is the new flu epidemic likely?
The news about the seals flu death has come just a short time after a new strain of a flu virus that lives in pigs has affected ten people in Iowa, most of them children. Fortunately, in their case, the symptoms were mild. But, influenza or flu has proven very difficult to deal with and almost impossible to predict or prevent. It keeps changing and adapting, and all we can do is keep adapting with it.
Scientists estimate that up to 50,000 people (the 2009 H1N1 pandemic) in the USA die every year from flu-related complications.
What is flu?
The flu is an infectious disease caused by influenza viruses. Viruses infect the respiratory tract -nose, lungs and throat and can cause serious illness, complications and even death. Older people, very young children, pregnant women, and people with some pre-existing conditions, are at high risk.
In the moderate climate like what we have in the USA, flu comes seasonally and we expect it with dread as the colder weather arrives. It is not clear why it happens, since in hot countries flu is present year around. It probably has to do with dry mucus in the nose because of the cold weather, or our habit to congregate indoors, making transferring of this contagious disease easy from person to person.
The best method for preventing flu is by getting a flu vaccination. It has to be done each year, since the vaccine has to be made fresh – it is made from live viruses.
How does virus jump from animals to people?
The scientists who studied the cause of death of harbor seals in New England and discovered the new variant of the flu virus published their findings in mBio ®, an online journal of the American Society for Microbiology. The virus came from birds, and adapted to infect mammals, immediately causing concern that it could spread to humans as well.
In order to infect a host, since they are parasites, viruses need a receptor. Once attached to a receptor, a virus can enter a cell and start the destruction. There are two kinds of receptors – in birds and in mammals. What is particularly dangerous about this virus variant is that it is capable of attaching itself to any of the two receptors. It was known that pigs got affected by a virus transmitted by birds, but the new information is that the seals have the same ability. Scientists are now working on finding out if the virus can affect terrestrial mammals.
What can we do?
The thoughts of epidemics are never far from our minds when it comes to flu. While often so mild and not worse than a common cold, flu virus can change into a monster that kills thousands of people in a blink of an eye. Doctors recommend making sure that everyone, and particularly kids and older people, are vaccinated for flu every year. Our own immune system is well able to defend us from many diseases if we are strong and healthy. Staying healthy is easier than fighting a disease. Good, balanced nutrition rich in fresh fruits and vegetables and regular physical exercises are the building blocks of good health. And even if the dreaded flu virus mutates and turns into something we do not have vaccine for, the symptoms of the disease are much milder in healthy people.