Influenza pandemic: overview and impact

¶ … spread?

Classification of the influenza virus

Definition of pandemic and causes and reasons for its spread

How well is USA prepared for the onset of the influenza virus?

The morbidity and mortality rates of the influenza virus

Details about WHO and CDC and their methods of tackling the disease

End Notes

Influenza Pandemic

What is Influenza and how does it spread:

Influenza is defined as a severe infection of the respiratory tract and is shown in the inflammation of the nasal mucosa and the pharynx and the eyes and the patient suffers from a headache and more often severe myalgia. He also suffers from chills, prostration, muscle aches, a sore throat and also, a dry cough. Influenza is also known as the flu and is described as an infectious disease caused by the inhalation of an infectious virus. It may become a life threatening disease in infants, the elderly, and some people whose immunity systems are compromised. It is highly contagious and, if unchecked, may cause an epidemic.

When the influenza virus becomes deposited in the respiratory tract of a person, the various signs and symptoms appear almost immediately. The onset of the symptoms is almost like being hit by a truck; this is how a patient may experience the virus. Some patients can even accurately pinpoint the time of the onset of the fever or chills or the cold. Some patients may face photophobia other ocular problems and though these are not very common symptoms, they may occur in some rare cases. In some children, there may be stomachache and vomiting and also a feeling of general malaise. In infants these may become difficult to diagnose and the treating physicians are warned against treating them as symptoms of an ordinary common cold, whose symptoms are very similar to those of influenza.

Influenza can cause morbidity as well as mortality if it is not treated on time. It is a fact that almost 10,000 deaths occur for every epidemic of influenza. The Center for the Prevention and Control of disease states that more than 20,000 people died of the influenza virus during each outbreak in the years 1972 to 1973, and in the years 1994 to 1995. There were about 11 flu epidemics in different parts of the U.S.A. during these years, and more than 40,000 per epidemic have been reported to die. The figure for the mortality rates for the years 1994 to 1995 due to the influenza virus is a high 8.7% in 122 cities of the U.S.A. All age groups are prone to this infection since it is extremely contagious and it makes its presence felt within hours after inhalation and incubation. However, the sad and very true fact is that very few elderly are able to survive the onset of this disease, and this is mainly due to its cardio-pulmonary and upper respiratory tract effects, and not because of the disease itself. The complications of the disease are generally rhinitis, sinusitis, bronchitis, and otitis media.

While it is true that the elderly are more prone to deaths from the influenza virus, the very young are also prone to severe infection that may eventually lead to death. The fact is that for every death occurring due to the virus, another 10 to 12 persons are taken to hospitals for the treatment of this dreaded disease. During the epidemics of the 1960's and the 1990's, more than 20,000 to 30,000 people were hospitalized for treatment. The influenza virus peaks its attacks during the months of November through April. While a 'widespread outbreak', according to the center for the Prevention of Disease and Control, is when the virus affects about 50% of the entire county population of the various states of the U.S.A., a 'regional outbreak' is when the virus affects less than half of the counties of any particular state of the U.S.A.

When an affected person sneezes or coughs or even talks, the virus is propelled into the air and it enters another person's system. This is how the influenza virus spreads. This is why persons taking part in any sort of indoor gathering, children at a school, and persons in a nursing school are all prone to the virus, and almost 20% to 50% of the entire community is affected immediately. School age children are primarily responsible for bringing the virus to their own homes and therefore affecting their parents who thereafter affect their workplace, from where the virus spreads easily to other places, like for example, the transportation network that the parent uses for traveling to his work and back, the places he visits during the course of his work, and so on.

Classification of the Influenza Virus:

The Influenza Virus is generally classified into three groups according to the differing nuclear proteins that they are made up of: Type A, Type B, and Type C. The first type, A, is capable of causing severe illness and the very fact that this deadly virus is prone to change its composition makes it extremely difficult to keep track of and this in turn makes it deadly and this type A virus is usually responsible for the outbreaks of 'pandemics'. The two key surface proteins of the type- A influenza virus are the hemagglutinin and the neuraminidase, that are also known as HA and NA respectively. These two 'subtypes' as they are known, demonstrate a different sequencing of their amino acids within each protein, and about 15 different subtypes of HA and about 9 different subtypes of NA have been identified so far.

Of these, only 5 HA subtype and 2 NA subtypes have been known to have infected human beings over the years. The other subtypes, though they do not affect humans, are known to survive in the environment in the bodies of hosts for long periods of time and some may infect horses, birds, and swine. The problem lies in identifying these various subtypes and creating antibodies for all of them. It is a sad fact that, every time an antibody is manufactured and named for the subtype it was made to fight against, another subtype is discovered, and an antibody has to be created for the new subtype too. Therefore it is important that these subtypes are identified immediately and antibodies manufactured as soon as possible. The protection of antibodies cannot be underestimated in any manner, and the better an antibody, the better the chances of recovery from this disease are.

However, the great problem faced by health institutions is that these viruses are capable of slow change, that is, they are capable of altering their constitution by a process of mutation and changes that occur in their amino acids that make up the hemagluttinin and the neuraminidase surface proteins. Therefore, a virus of type A or of type B, after it has established itself in the host, can adapt and survive. Thus, an influenza virus that undergoes an antigenic shift may become capable of changing its constitution and may live for years, unhindered. This in turn may make it difficult for the person treating the infection to identify it as belonging to a particular type, and this in turn will cause the patient untold misery, because unless proper diagnosis and treatment of the virus with appropriate antibodies are accomplished, the patient will know no relief. When the virus is undiagnosed and allowed to grow unchecked, there will be an epidemic. The cycle goes on uninterrupted: when an antibody is discovered to fight a particular strain of the virus, the virus mutates, and the antibody then becomes useless. By the time this is discovered and a new antibody is manufactured, the virus has learnt to survive by repeatedly mutating in different ways, and the specific antibody will not work.

Pandemic' and the causes for its spread:

The end result of this endless antigenic shifting as well as of antigenic drifting of the influenza virus is the epidemic and eventually the pandemic. The dictionary definition of 'pandemic' is an epidemic that is widespread, geographically, occurring throughout a particular region or even all over the world. A pandemic, in other words, is larger than an epidemic. (Hyperdictionary) Therefore, the implications of a pandemic are definitely larger than those of an epidemic and it is infinitely more dangerous and risky to be in the throes of a pandemic. A solution will have to be found to combat the influenza virus before it can become uncontrollable. In order to do this, one has to learn how the virus multiplies and escapes from every antibody invented by man. Suppose that a new virus-call it type 'A HxNx' was brought into a group of people for whom there was no antibody against this particular virus. What would happen is that the virus would spread uncontrolled throughout the world, thus causing a pandemic.

However, after a period of exposure to the new virus, antibodies would be introduced to fight it, and this would result in the formation of new variations of the virus, which is actually fighting against the increased resistance to it by human beings and other living creatures. As the resistance increases, so does the pressure on the virus to develop a new variant strain, which, in other words, is referred to as the 'antigenic drift'. If all these newly formed and slightly different viruses have the capability of entering a living creature as a virus infection, then they end up being the cause of endlessly repeating epidemics. However, when this happens, the result is that the resistance to these viruses increases, and at the end of, for example, ten years, an entire population becomes immune to the virus and can resist the onset of the virus. What happens now is that 'antigenic shift' or genetic reassortment happens and an entirely different and new form of the original virus is ready to spread. The environment is also ripe to spread the virus. The new virus - 'A Hy Ny' spreads through an entire group of population that has no known antibody with which to fight it off. The result, once again, is the onset of a pandemic, which affects the whole world.

There have been numerous instances of the occurrence of pandemics all over the world. Some of the most devastating ones were as follows: in the year 1918, a large number of soldiers at an army base at Boston started becoming infected with the influenza virus, but of an unknown strain of the same. Soon the soldiers began to die in huge numbers. There was no room in hospitals for these unfortunate people, and they were buried in mass graves. At the end of it there were to be more than 600,000 dead, and the disease disappeared by itself after wreaking enough destruction on humanity. In the fall of 1918, a new virus took hold of humanity, and killed with amazing rapidity. Those afflicted with this virus, also known as the Spanish Flu and Swine Fever, died within hours of getting infected, and the death was horrible and terrifying.

The victim would have his lungs fill with blood because of hemorrhaging, and he would be coughing up blood at the end of just a few hours after the onset of the disease. It was so frightening to onlookers that they actually believed that the world was coming to an end because all the people were dying so very rapidly. The worst part of this epidemic was that it strangely targeted the young and the healthy, more than the elderly and the very young. The figures for the deaths that occurred during the year's from1918 to 1919 show that almost 675,000 Americans died, and 30 to 450 million people were believed dead world wide due to this virus.

The year's 1957 to 1958 single-handedly caused over 70,000 deaths of Americans. The virus named the 'Asian Flu' caused this and the particular strain of the influenza virus was of the type A (H2N2). The virus was an avian virus that was easily transferred to human beings. The good news is that this type if influenza virus no longer exists and is therefore of no further threat to humans anywhere in the world. The 'Hong Kong Flu' of 1968 to 1969 ended up killing about 34,000 people. Caused by the virus type H3N2, the virus is known for its extreme rates of morbidity as well as of mortality. Persons who had already been exposed to the H2N2 virus some previous years had developed immunity to this particular virus. However, more than 400,000 elderly Americans have died in the past 30 years due to the onslaught of this virus.

In the year 1997, a new strain of the influenza virus that was previously only found in birds was found to have infected human beings. This virus came to be known as the H5N1, and also as the 'Chicken Ebola'. The virus was believed to have entered the bodies of humans from contact with birds like poultry. When more than one third of the first 18 cases died of this particular virus in Hong Kong, panic reigned, and the officials of Hong Kong ordered the slaughter of the entire population of poultry in the city, including ducks, chicken, and geese. To everyone's immense relief, it was eventually discovered that this particular strain of the virus could not actually transfer itself from one human host to another potential human host through the air, like in other previous strains of the influenza virus.

The latest strain of influenza that was detected was in the year 1999. This was the H9N2 virus and it affected about 5 human beings. These people complained of mild flu like symptoms and were able to recover completely. There were no deaths. What is important now is that some sort of plan has to be developed by the authorities to combat this deadly virus, influenza. The potential for the emergence of a totally new strain of the virus is very much possible and this has to be remembered at all times. A pandemic will inevitably happen and nobody knows what the result of a pandemic at this time would be. Both young and old people are at risk from this virus, and no one person can escape its onslaught. Therefore, the need for a pandemic fighting plan is vitally important, and this includes plans for the immediate and rapid detection of the new strains of the virus that influenza may bring into the picture and the constant watch by veterinarians for the new anti-viral agents that may exist in animals and birds.

How well is USA prepared for the onset of the influenza virus?

Is USA prepared for the eventuality of the next attack of the influenza virus? The answer is, according to some experts in the field of research at St. Jude Children's Research Hospital in Tennessee, a definite 'NO'. These experts say that the U.S.A. is one of the most ill prepared countries in the world as far as planning and preparing for a pandemic of influenza is concerned. The legislature as well as the infrastructure is not at all prepared for change, and in the eventuality of an influenza outbreak, the health of the public is definitely at stake. This is despite the fact that vaccines to tackle a large scale outbreak are readily available and all the government would have to do is to be well prepared in advance with an abundance of antibody vaccines, since one can never be sure of the scale of the attack. However, the production facilities that would be in charge of producing the vaccine are not at all adequate to handle large scale production of the vaccine, and if this were not done, fighting the pandemic when it occurs will be an extremely difficult task. Why is this so? It is because the existing stock of the antibody to fight the influenza virus will only last for a mere few days when there is a pandemic. What will happen then?

It is difficult to predict the scale of the disaster in the case of a pandemic when it happens without the safety net of the vaccine. The only answer is to start the manufacture of the vaccine immediately and stock pile it for future use. The production of the vaccine from start to finish generally takes about 18 months; since it involves a long process of allowing the genes of a specific virus mix with the eggs of a chicken that would generally include the genes of a virus that would be safe for use for human beings. These viruses would carry the proteins of hemagglutinin and neuraminidase, both of which, when mixed together, would produce the immune response in a human being that would fight the influenza virus. The whole process is slow and would be quite expensive and time and resource consuming, and there is no way that the medicine could be produced after the outbreak of a pandemic.

The practical way to go about solving the problem would be to manufacture and then stock it in large quantities so that it is always available for whoever may need it at any time. There has in fact been adequate warning of an impending influenza attack in the form of the 'Avian' or 'Bird Flu' that spread from birds like poultry to humans. This strain of virus was hitherto unheard of and transmission from a different species to human beings was also a first timer. The H5N1 virus affected Hong Kong, and the Netherlands found itself facing the H7N7 virus. While there was a single death of an Asian man due to the H5N1 virus, a large number of people of almost 80 were affected in the Netherlands by the H7N7 virus. All these people were workers on a chicken farm and this is how the virus was transmitted.

Experts feel that it was indeed fortunate that the virus was not able to spread from one human to another through the air or through physical contact. If this had happened, they feel, there would have been a pandemic and the virus would have infected people from all over the world. Research is being conducted in some laboratories in the U.S.A. And elsewhere to reduce the amount of time taken to produce the influenza antibody vaccine in sufficient quantities. One such laboratory is the one at the St. Jude Children's Research Hospital. The team led by Dr. Richard Webby who is an Assistant Member of the St. Jude Institute of Virology, has developed a new technique for developing the 'seed' virus, which is, in other words, the starting point in the production of the viral mix that would eventually produce the vaccine. This team of skilled technicians has shortened the production of the seed that generally takes a long time of 18 months to be produced from start to finish.

This new process has been termed 'reverse genetics', and it was used to produce a seed vaccine that would fight the H5N1 strain of the influenza virus. The procedure was to mix two genes from the H5N1 virus with six genes of another virus, and thereby produce a virus that was safe for humans and would also contain the proteins H. And N. that usually made the immune system of human beings function. The time consumed for the making of the seed vaccine is much less when compared to conservative methods, and this is where the advantage lies. However, the virus has to be grown in chick eggs to produce the vaccine, much like the older method of growing the virus in an egg. When the influenza virus strikes, the entire world has to be prepared for it. The whole world has to combine its efforts in fighting this disease. International collaboration is therefore not necessary but essential and imperative in combining resources and efforts. The governments, the industry, and the academia of different countries of the world have to come together as one to combat influenza. The vaccines have to be prepared well in advance and also tested on human beings for their efficacy and safety, so that when there is an attack of influenza, there will not be a pandemic.

The morbidity and mortality rates of the influenza virus:

The inherent nature of the influenza virus that changes its genes with every attack- changing antigenicity makes it an extremely difficult disease to control or even diagnose, and the vaccines needed to combat the influx of the virus causing the disease is difficult to produce in large quantities. When influenza happens, it is difficult to diagnose because the strain of virus that has manifested itself this time round may be different from that of the previous time. However, when it is during the influenza season, physicians find it easy to diagnose, since 85% of the time the disease causes symptoms of cold, cough, fever, and myalgia. Culturing the viral antigens gives definite proof of the presence for the influenza virus in case of any doubts, but the normal method of testing used by almost all laboratories of repute called 'commercial enzyme immunoassay' ultimately takes a long time because the culture has to grow and then reproduce in order to recognize and alienate the virus.

It does take only a few minutes in some cases, but this is rare. Sometimes it happens that the test will only detect the presence of influenza type A only, or of influenza type A and B. only. The quickest means of diagnosing accurately an influenza infection is by following the method of clinical presentation and combining it with the present epidemiological context, and utilizing the diagnostic tools at the physician's disposal in a judicious manner. Testing and rapid diagnosis helps physicians prescribe medicines for their patients accurately, especially when elderly or the very young are concerned, or when the patient is one with a compromised immune system. The doctor need not prescribe antibiotic drugs needlessly for these patients, and the medical costs can be reduced by the doctors being able to discharge the patient sooner than he would if it was a genuine case of influenza.

Another advantage of these rapid tests is that when the virus, if present, is detected early, preventive measures can be taken immediately, and the virus could be contained to a large extent within the institution where it was diagnosed. The fact remains that another pandemic of influenza is in the offing, and it is advisable for all physicians and health care personnel to be aware of the means of testing and diagnosis of this deadly disease, and the ways in which it can be prevented as well as treated. It is only by following certain well researched and documented methods that morbidity as well as mortality due to the influenza virus can be prevented and tested and recognized and treated.

Details about WHO and CDC and methods of tackling the disease:

The Prevention and treatment of influenza has become an issue of worldwide concern and organizations for world health like the World Health Organization-WHO are doing their bit to demonstrate their concern for the well being of humanity. The WHO has prepared a document in which it has outlined its plans for tackling the influenza virus when it appears. It collects and analyses all the data that is available on the subject so that it will be ready in the case of any eventuality. The WHO also provides other organizations around the world that deal with issues on health with such information that they would be able to use and learn from and prepare themselves and the institutions in which they are employed to understand the workings of the influenza virus. It also informs the general public as well as the media about the latest advancements in medicine and the latest testing methods in which to isolate the virus so that all this information is public and the people who want to educate themselves and be prepared can do so. The WHO reveals up-to-date information to whoever want it on its well maintained web site: http://www.who.int/emc/diseases/flu/index.html, and submits weekly reports on the newest developments on the virus on the web site: http://www.who.int/emc/diseases/flu/index.html.

Programs are organized in which doctors and officials of influenza centers and health organizations are invited to take part in where they are apprised of the global situation of the influenza virus, and the various measures being taken to tackle it. Policy makers at the national level are helped in making any policies concerning influenza by suggesting various proposals to this effect. In this way, the recommendations of a reputed and renowned organization such as the WHO will be considered and action will be taken according to these suggestions. The Planning for the eventuality of an attack of influenza is as important as the treatment of the disease itself. This sort of planning will prepare doctors and others to recognize a new virus when it is formed and not be surprised and bewildered when confronted with it. Responses are therefore regulated to deal with a new strain and when this is done, half the battle is won. The WHO recommends levels of preparedness wherein Preparedness Levels 1, 2, and 3 would deal with those events that may occur in between pandemics.

The WHO would therefore maintain a plan of preparedness for use during these times and this would include the appropriate measures to be taken on an international and national level to help the concerned authorities when a pandemic occurs. When the WHO confirms the presence of a new virus in a human being after analyzing such reports and also conducting a series of tests of its own to confirm these reports, the second level of preparedness, which is Preparedness Level 2, is put into action. National level investigations will than be undertaken to assess the new virus and the ways and means with which to fight it. International co-operation will also be sought by the WHO as one of the means of comparison of the virus with any previous ones that may have attached human beings of the other countries. Such a method is very crucial in defining the nature of the new virus. Further to this, contingency plans of the country where the virus has struck will be analyzed, and its effectiveness and validity will be estimated.