nza, commonly known as the flu, is a respiratory illness caused by viruses. There are many different types of flu, from swine flu to the most feared avian flu. This article, however, deals only with the so-called common or seasonal flu. The flu season usually starts in the fall and subsides in late spring. Because of its seasonality, the flu season differs between the Northern and the Southern hemisphere.

On the global scale, flu can affect tens of millions of people and cause 250,000 to 500,000 deaths each year. The United States CDC gives the following statistics. Yearly 5 to 20% of the population get the flu, 200,000 cases are hospitalized due to severe flu complications and 36,000 cases prove to be fatal. Annual healthcare costs approaches US$10 billion

THE FLU is caused by types A, B and C. Each type consists of different subtypes and substrains with A and B being responsible for most epidemics.

(1) Influenza A viruses are of subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). The current subtypes of influenza A viruses in humans are A (H1N1) and A (H3N2).

(2) Influenza B viruses do not have subtypes but can be further broken down into different strains.

(3) Influenza C seems to be relatively benign compared to the first two and is not as contagious.

Like many viruses, influenza viruses change with time producing new strains each season. This change occurs by antigenic drift or shift.

(1) Antigenic drift is slow and can lead to new strains after several seasons and is the typical change observed in influenza type B viruses but can also occur in type A.

(2) Antigenic shift happens abruptly and creates a major change that can lead to a new subtype but only occurs in type A.

The influenza viruses attack the epithelial cells lining the respiratory tract starting from the nose, throat, and down to the lungs. They do this by binding using hemagglutinin and neuraminidase proteins on the cells’ surface.

Influenza symptoms may be mild to severe to life-threatening. Symptoms can include high fever, headache, chills, sore muscles, fatigue, dry cough, red, watery eyes, sore throat and runny or stuffy nose. The so-called “tummy flu” symptoms may also occur in children, which include abdominal pain, vomiting, and diarrhea.

The flu symptoms shouldn’t be confused with the ordinary cold, which is another respiratory illness. A cold usually doesn’t cause high fever, muscle pains or stomach symptoms.

The incubation period of the flu can vary from a few days to a week. During this “asymptomatic period”, the infected person is already a carrier of the disease and is therefore highly contagious. The flu can last from a few days to less than two weeks. However, in certain cases, complications can develop which are potentially life-threatening. Some of these complications are bronchitis, pneumonia, sinusitis, and ear infections. Anybody can get the flu but those who are highly susceptible to the flu are young children, the elderly and those with existing chronic health conditions and weakened immune systems.

Flu is very contagious. Direct transmission occurs from person to person via droplets that are released when a person coughs or sneezes. Indirect transmission happens when droplets from an infected person are transferred to inanimate objects, which are then touched by another person.

Flu-like symptoms can also occur with many other diseases. It is therefore sometimes difficult for doctors to diagnose the illness. There are many laboratory tests which can confirm whether a person has the flu or not but they cost money and time and are therefore impractical. However, in times of outbreaks and epidemics, it is important to perform tests. Usually, flu cases are diagnosed based on tests performed in a few individuals within a group. If one or two persons test positive for the flu in a closed environment, then the likelihood of subsequent illnesses within the group as being flu is rather high. Samples for flu testing are usually secretions from the nose and the throat, collected either by sterile swab, nasal wash, or aspiration. There are rapid influenza tests which can give results in 30 minutes. The tests are 70% sensitive in detecting the flu and are prone to false negatives. Another alternative is the more reliable but time consuming viral culture which takes about 3 to 10 days.

Several antiviral pharmacological agents have been approved for the treatment of the flu. Because of the seasonal changes in the types and strains of influenza viruses the recommended anti-flu drugs may change. This season, Tamiflu is the choice for treatment and chemoprophylaxis of persons aged 1 year and older and Relenza is approved for treatment of persons aged 7 years and older. Currently, the CDC discourages the use of previously used anti-flu drugs such as Amantadine and Rimantadine because the current circulating strains of flu viruses are resistant to these drugs.

The ultimate preventive measure against the flu is vaccination. However, again due to the constantly changing nature of the influenza viruses, flu vaccines do not afford 100% and lifetime immunity against the flu. Each season, flu vaccines are updated by adding strains collected and identified from the previous season. Flu vaccines contain different strains of the influenza types A and B but not type C.

Based on the 2005 guidelines of the Federal Advisory Committee on Immunization Practices (ACIP), annual flu shots are recommended for children aged 6 months to 5 years old and adolescents up to 18 years old. Vaccination is also highly recommended for people in key professions which may expose them to the infection and spread it to others. These include health care professionals and those working and living in closed units such as dormitories. Flu shots are usually given prior to flu season and afford protection for about a year. However, it takes about two weeks before the protection kicks in.

Over the years, several types of flu vaccines have been developed.

(1) The intranasal vaccine is the live, attenuated influenza vaccine (LAIV) made from living but weakened flu viruses. LAIV is prescribed for people aged 2 to 49 years old. LAIV should not be given to pregnant women, children under 2 years old, adults above 40 years old, and chronic medical conditions including compromised immune system disorders.

(2) The inactivated vaccine, the common flu shot is made from different strains of killed flu viruses. This vaccine is recommended for children from 6 months to 18 years old as well as those older than 50 years old. In addition, people who are not qualified to receive LAIV (as listed above) are recommended to have this vaccine.

Like all pharmacological agents, flu shots can have some side effects. Most of these side effects are mild. Rare severe side effects, mainly in the form of allergic reactions have been reported.

Some inactivated flu vaccines have contained thimerosal in the past, a form of mercury used as preservatives for vaccines. In recent years, there have been concerns about the link between thimerosal and autism in children. This controversy continues although no ample scientific evidence is available to prove this link.

Perhaps the main shortcoming of the flu shot is its efficacy, which is highly dependent on how well the vaccine is matched to the circulating influenza viruses of that season. For this reason, the efficacy of the vaccine in protecting healthy adults from the flu is only 70 to 90% and even less in children and the elderly.

The Global Influenza Surveillance Network (GISN) was set up in 1952 and currently includes more than 110 laboratories in 83 countries. It has recently set up FluNet, a web-based tool for surveillance, reporting, and alert mechanisms. The European Influenza Surveillance Scheme (EISS) issues a weekly report on influenza activity in 30 countries. It collects data from a network of more than 25,000 sentinel doctors covering a total population of 498 million people in Europe. In the US, the CDC is responsible for national influenza surveillance and is dependent on reports from more than 1500 sentinel doctors.

Google Flu Trends, being the new kid on the block, claims that it can estimate flu activity up “to two weeks faster than traditional flu surveillance systems” and bases its predictions on the number of people searching for flu-related topics. Actually its data compared well with the CDC’s. Google is now working together with the CDC in flu surveillance and their work has been published in the prestigious scientific journal Nature. Google Flu Trends also presents the data in graphs, maps, and animations which are easy to comprehend by the general public.

Don’t forget the CDC’s initiative “Take 3″ Steps To Fight The Flu; take time to get a flu vaccine, take everyday preventive actions and take flu antiviral drugs if your doctor recommends them.

And if you are still unlucky and get the flu, stay home from work or school including limiting contact with others, wash your hands often with soap and water and avoid touching your eyes, nose or mouth.

http://www.google.com

nza, commonly known as the flu, is a respiratory illness caused by viruses. There are many different types of flu, from swine flu to the most feared avian flu. This article, however, deals only with the so-called common or seasonal flu. The flu season usually starts in the fall and subsides in late spring. Because of its seasonality, the flu season differs between the Northern and the Southern hemisphere.

On the global scale, flu can affect tens of millions of people and cause 250,000 to 500,000 deaths each year. The United States CDC gives the following statistics. Yearly 5 to 20% of the population get the flu, 200,000 cases are hospitalized due to severe flu complications and 36,000 cases prove to be fatal. Annual healthcare costs approaches US$10 billion

THE FLU is caused by types A, B and C. Each type consists of different subtypes and substrains with A and B being responsible for most epidemics.

(1) Influenza A viruses are of subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). The current subtypes of influenza A viruses in humans are A (H1N1) and A (H3N2).

(2) Influenza B viruses do not have subtypes but can be further broken down into different strains.

(3) Influenza C seems to be relatively benign compared to the first two and is not as contagious.

Like many viruses, influenza viruses change with time producing new strains each season. This change occurs by antigenic drift or shift.

(1) Antigenic drift is slow and can lead to new strains after several seasons and is the typical change observed in influenza type B viruses but can also occur in type A.

(2) Antigenic shift happens abruptly and creates a major change that can lead to a new subtype but only occurs in type A.

The influenza viruses attack the epithelial cells lining the respiratory tract starting from the nose, throat, and down to the lungs. They do this by binding using hemagglutinin and neuraminidase proteins on the cells’ surface.

Influenza symptoms may be mild to severe to life-threatening. Symptoms can include high fever, headache, chills, sore muscles, fatigue, dry cough, red, watery eyes, sore throat and runny or stuffy nose. The so-called “tummy flu” symptoms may also occur in children, which include abdominal pain, vomiting, and diarrhea.

The flu symptoms shouldn’t be confused with the ordinary cold, which is another respiratory illness. A cold usually doesn’t cause high fever, muscle pains or stomach symptoms.

The incubation period of the flu can vary from a few days to a week. During this “asymptomatic period”, the infected person is already a carrier of the disease and is therefore highly contagious. The flu can last from a few days to less than two weeks. However, in certain cases, complications can develop which are potentially life-threatening. Some of these complications are bronchitis, pneumonia, sinusitis, and ear infections. Anybody can get the flu but those who are highly susceptible to the flu are young children, the elderly and those with existing chronic health conditions and weakened immune systems.

Flu is very contagious. Direct transmission occurs from person to person via droplets that are released when a person coughs or sneezes. Indirect transmission happens when droplets from an infected person are transferred to inanimate objects, which are then touched by another person.

Flu-like symptoms can also occur with many other diseases. It is therefore sometimes difficult for doctors to diagnose the illness. There are many laboratory tests which can confirm whether a person has the flu or not but they cost money and time and are therefore impractical. However, in times of outbreaks and epidemics, it is important to perform tests. Usually, flu cases are diagnosed based on tests performed in a few individuals within a group. If one or two persons test positive for the flu in a closed environment, then the likelihood of subsequent illnesses within the group as being flu is rather high. Samples for flu testing are usually secretions from the nose and the throat, collected either by sterile swab, nasal wash, or aspiration. There are rapid influenza tests which can give results in 30 minutes. The tests are 70% sensitive in detecting the flu and are prone to false negatives. Another alternative is the more reliable but time consuming viral culture which takes about 3 to 10 days.

Several antiviral pharmacological agents have been approved for the treatment of the flu. Because of the seasonal changes in the types and strains of influenza viruses the recommended anti-flu drugs may change. This season, Tamiflu is the choice for treatment and chemoprophylaxis of persons aged 1 year and older and Relenza is approved for treatment of persons aged 7 years and older. Currently, the CDC discourages the use of previously used anti-flu drugs such as Amantadine and Rimantadine because the current circulating strains of flu viruses are resistant to these drugs.

The ultimate preventive measure against the flu is vaccination. However, again due to the constantly changing nature of the influenza viruses, flu vaccines do not afford 100% and lifetime immunity against the flu. Each season, flu vaccines are updated by adding strains collected and identified from the previous season. Flu vaccines contain different strains of the influenza types A and B but not type C.

Based on the 2005 guidelines of the Federal Advisory Committee on Immunization Practices (ACIP), annual flu shots are recommended for children aged 6 months to 5 years old and adolescents up to 18 years old. Vaccination is also highly recommended for people in key professions which may expose them to the infection and spread it to others. These include health care professionals and those working and living in closed units such as dormitories. Flu shots are usually given prior to flu season and afford protection for about a year. However, it takes about two weeks before the protection kicks in.

Over the years, several types of flu vaccines have been developed.

(1) The intranasal vaccine is the live, attenuated influenza vaccine (LAIV) made from living but weakened flu viruses. LAIV is prescribed for people aged 2 to 49 years old. LAIV should not be given to pregnant women, children under 2 years old, adults above 40 years old, and chronic medical conditions including compromised immune system disorders.

(2) The inactivated vaccine, the common flu shot is made from different strains of killed flu viruses. This vaccine is recommended for children from 6 months to 18 years old as well as those older than 50 years old. In addition, people who are not qualified to receive LAIV (as listed above) are recommended to have this vaccine.

Like all pharmacological agents, flu shots can have some side effects. Most of these side effects are mild. Rare severe side effects, mainly in the form of allergic reactions have been reported.

Some inactivated flu vaccines have contained thimerosal in the past, a form of mercury used as preservatives for vaccines. In recent years, there have been concerns about the link between thimerosal and autism in children. This controversy continues although no ample scientific evidence is available to prove this link.

Perhaps the main shortcoming of the flu shot is its efficacy, which is highly dependent on how well the vaccine is matched to the circulating influenza viruses of that season. For this reason, the efficacy of the vaccine in protecting healthy adults from the flu is only 70 to 90% and even less in children and the elderly.

The Global Influenza Surveillance Network (GISN) was set up in 1952 and currently includes more than 110 laboratories in 83 countries. It has recently set up FluNet, a web-based tool for surveillance, reporting, and alert mechanisms. The European Influenza Surveillance Scheme (EISS) issues a weekly report on influenza activity in 30 countries. It collects data from a network of more than 25,000 sentinel doctors covering a total population of 498 million people in Europe. In the US, the CDC is responsible for national influenza surveillance and is dependent on reports from more than 1500 sentinel doctors.

Google Flu Trends, being the new kid on the block, claims that it can estimate flu activity up “to two weeks faster than traditional flu surveillance systems” and bases its predictions on the number of people searching for flu-related topics. Actually its data compared well with the CDC’s. Google is now working together with the CDC in flu surveillance and their work has been published in the prestigious scientific journal Nature. Google Flu Trends also presents the data in graphs, maps, and animations which are easy to comprehend by the general public.

Don’t forget the CDC’s initiative “Take 3″ Steps To Fight The Flu; take time to get a flu vaccine, take everyday preventive actions and take flu antiviral drugs if your doctor recommends them.

And if you are still unlucky and get the flu, stay home from work or school including limiting contact with others, wash your hands often with soap and water and avoid touching your eyes, nose or mouth.

http://www.google.com

gh the chances of your catching swine flu are relatively low, it is still possible you could become infected. But if it does happen, don’t lose hope. The virus can be fought with natural immune system boosters and antiviral substances. During this pandemic, natural remedies can help you recover from even a deadly disease.

Furthermore, proper natural remedies can help prevent you from catching this disease, or any disease, in the first place. By strengthening your immune system, you increase your body’s ability to fight disease, viruses, and bacteria.

One way to boost your immune system is to take large amounts of Vitamin C. This antiviral vitamin can block the enzyme known as neuraminidase, which is needed by a virus in order to reproduce. There are anecdotes of people surviving the Spanish Flu by drinking large doses of Vitamin C. The elderly should take Vitamin E along with Vitamin C, to enhance the effects of the vitamin.

Garlic is common in most kitchens and it can also be used in the fight against the swine flu epidemic. It is an efficient natural antiviral herb. It is most potent when freshly crushed. Garlic must be consumed within one hour of crushing. Recommended dosage is two to three cloves per day. Organic garlic is more potent and effective than non-organic garlic. But remember that it can burn the stomach when taken in large amounts, so its a good idea to eat it with bread or yogurt.

My favorite way of taking large amounts of garlic, to fight normal colds and flues, is by spreading butter on toast and then adding garlic slices, or crushed garlic.

Possibly the best alternative to the medical drugs, Tamiflu and Relenza, is Green Tea. This is a highly effective antiviral. It decreases the production of the cytokine TNF-a, and inhibits the reproduction of neuraminidase as well. Best of all, it is natural, and therefore it doesn’t have any of the harsh side effects that synthetic drugs have. If you want to use Green Tea for this purpose, remember that what you find on the shelves of a grocery store will probably be relatively ineffective. Organic varieties, particularly those grown for health or medicinal purposes, are the best.

Another antiviral you can get is Resveratrol. It comes from the Japanese Knotwood root, from red grapes, and from raisins. It causes your cells to stop manufacturing viruses. There are supplements available in liquid form, for better absorption, and it has no toxic effects.

Apple juice is an antiviral which is available just about everywhere. But if you want to have the best results, try making your own, in a juicer. You should include the skin and pulp. This is more powerful than simply using commercially-available apple juice.

Scuttellaria, better known as Skullcap, is an herb that can be taken as tea. It is an effective antiviral that is also used as a mild tranquilizer. Just like other natural antivirals, it inhibits the reproduction of neuraminidase.

Cat’s Claw, or Uncaria Tomentosa, boosts one’s immune system as well as decreasing the production of cytokine TNF-a. Your white blood cell count can be increased with this treatment. Although no toxicity is noted, however, it should not be used by children and pregnant women. This is due to its damaging effect on the DNA of growing cells.

There are still plenty of other natural treatments for the swine flu that you can find in your cupboard. You don’t necessarily need to drink synthetic medicines, or get vaccinations that can be harmful to your body.

Disclaimer: This article does not constitute medical advice. If you are ill, you should consult your doctor.

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What makes swine flu so dangerous is that like all influenza viruses it undergoes the process of antigenic drift. This is when spot mutations occur on the genetic material that causes slight changes in the physical make-up of the virus.

These slight changes are what frustrate scientist’s attempts to create the ultimate vaccination for influenza. Due to constant changes to the protein particles of the outer coats of viruses (which the immune system is targeted for during vaccination) new vaccines are always needed to combat ever new versions of the viruses.

Swine flu is an example of such a change. But what are these changes and what parts of the virus causes the damage that destroys normal healthy cells?

The H1N1 designation of the swine flu virus gives us a clue to the inner workings of the virus. It represents the major functional proteins on its surface.

The ‘H’ stands for hemagglutinin which is a protein that binds the swine flu virus to the cell and injects its content into it.

The ‘N’ stands for neuraminidase which possesses a number of specialized enzymes that causes the infected cells to release the newly formed viruses.

All these aspects of swine flu make it potentially very dangerous. Even though the form that is currently spreading is relatively mild it could still change into a virulent strain in the next few months before winter arrives. The fact that it’s also a new disease means that there is no current vaccine for swine flu. So if it becomes more deadly, we will have no protection against it except for those provided by generic anti-viral drugs like Tamiflu and Relenza.

Tamiflu works by blocking the action of neuroamindase, obstructing the flu virus’s ability to spread from one cell to the other. But it is only effective as a treatment if it is used in the first few days during the onset of swine flu. The problem with anti-viral drugs is that it is often very difficult to diagnose the onset of swine flu. By the time the disease is identified it’s often too late to use the drugs. This is one of the reasons the effectiveness of anti-virals drugs has been called into question.

So we are currently exposed to the full potential of swine flu. We know the devastation that influenza viruses can cause, the Spanish flu pandemic infected more than one third of the world’s population and killed more than 50 million people.

We have no choice but to be vigilant to the spread of swine flu. Millions will undoubtedly catch the disease and many more will die from it. All we can do is hope that it doesn’t become more virulent and cause too much death. In its current mild form we can contain it and can control the worse of its symptoms through the use of anti-viral drugs. But if it changes we could be in trouble. Even the vaccines that are currently been developed might not be as effective if the change is marked. What we have to remember is that it is dangerous because it is so changeable and in light of this we have no choice but to treat it with extreme caution.

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What is Avian Influenza?

As the name suggests, avian influenza refers to the infection caused by avian (bird) influenza (flu) viruses. These viruses are commonly found in intestines of wild birds and these birds can carry the viruses without getting sick. However the viruses can be pathogenic to domesticated birds like chickens, ducks and turkeys. Domesticated birds become infected through exposure to other birds or through surfaces contaminated by secretions and faeces of the infected birds.

These viruses are classified as Low Pathogenicity and High Pathogenicity. Most strains of Avian Influenza come under Low Pathogenicity Avian Influenza (LPAI) Group and produce mild symptoms in the infected birds. Common symptoms are ruffled feathers, decreased food appetite, decreased egg production, sneezing and coughing. Many times LPAI may go undetected.

High Pathogenicity Avian Influenza (HPAI) has more severe symptoms which include sudden death, loss of energy and appetite, decreased egg production, respiratory problems, ****** oedema (swelling), poorly formed eggs and diarrhoea. HPAI can reach a mortality rate of nearly 100%.

What Is H5N1 strain of Bird Flu?

All flu viruses are classified as type A, B or C depending on their structural arrangement. Type A is responsible for lethal pandemics and is found in both animals and humans. Type B causes local outbreaks of flu. Type C is the most stable of the three and infected people show only mild symptoms of flu. Type B and C are usually found only in humans. Type B and C are more stable than type A and are not classified according to their subtypes.

Influenza viruses of type A are divided into subtypes and the naming is done on the basis of two proteins (antigens) found on their surface – Hemagglutinin (HA) and Neuraminidase (NA). Sixteen types of HA and nine types of NA exist. Thus a total 144 combinations are possible.

Thus H5N1 is a type A virus and gets its name from HA 5 protein and NA 1 protein present on its surface.

How Do Type A Viruses Cause A Pandemic?

Type A viruses are further classified into strains. These strains can continuously evolve into different strains. Their ability to exchange genetic material with other viruses and create new influenza viruses makes them unpredictable and difficult to fight with. Humans have to develop new immunity (antibodies) every time new strains are created.

Viruses cannot repair genetic damage, small changes known as “Antigen Drift”, are continuously creating new strains of viruses. However when genetic material from Type A viruses from different species – say a bird and a human, comes together and merges, an entirely new strain is created. This is known as “Antigen Shift” Humans have no immunity to such a strain and the strain can spread rapidly causing a Pandemic.

How Is The Virus Transmitted To Humans From Birds?

Usually Avian Influenza viruses do not infect humans. Migratory birds act as carriers of these viruses and do not get affected by them. These birds then come in contact with domesticated birds such as chickens and turkeys and spread the infection to them. Domesticated birds may get the virus from contact with contaminated surfaces too. Once a virus infects domesticated birds, it can cause severe epidemic among the birds. Humans come in contact with infected birds or contaminated surfaces and pick up the virus.

In the human body, this avian flu virus then undergoes an antigenic shift, combines with genetic material of a human strain of influenza virus and creates an entirely new strain of virus against which humans have little or no immunity. These genetic reassortments may also take place is the body of a third species (susceptible to both avian and human viruses) like the pig, where an avian influenza A virus and human influenza virus mix their genetic information and produce a new virus which might be able to infect humans.

Why is H5N1 dangerous?

The first reported cases of H5N1 infections were detected in geese in 1997 in Southern China. A total of 18 human infections were reported and six of them succumbed to it. The infection spread quickly to poultry in Hong Kong. At that time a million and half chickens were culled in Hong Kong to keep the virus under control. The virus disappeared for a few years, but resurfaced in 2002 in Hong Kong again. Since then it has killed millions of birds in Asia and many cases of human infections have been reported.

The persistence of this H5N1 strain of virus is a great concern for humans. Although the virus does not spread from birds to humans easily, the severity of the infection of H5N1 in humans is frightening. The virus has killed every second person infected by it. These cases were reported in perfectly healthy individuals who had no past history of infections. However the greater concern for the world is the POSSIBILITY THAT THE VIRUS MAY MUTATE (UNDERGO ANTIGENIC SHIFT) AND CREATE A FORM THAT MAY SPREAD FROM HUMAN TO HUMAN. Such a strain of virus may result in a pandemic, killing millions of people worldwide.

Is Consumption Of Poultry Birds Safe?

Yes, it is safe to consume THOROUGHLY COOKED poultry products. The H5N1 virus is sensitive to heat and gets destroyed by normal cooking temperatures of 70- 100 degree Celsius. If meat from poultry birds and eggs are cooked properly, the virus will be destroyed. Just make sure that no part of the meat remains raw or uncooked.

How Big Is The Risk Of A Pandemic Breaking Out?

The world had to face a Bird Flu Pandemic, thrice in the twentieth century. In 1918-1919, “Spanish Flu” killed anywhere between 20 million to 50 million people (exact figures not known), including half a million in the United States alone. The “Asian flu” in 1957-58 killed 70,000 in the United States and in 1968-1969, the “Hong Kong flu” killed 34,000 in the USA.

Currently the risk of H5N1 strain leading to a Pandemic is high. The virus is spreading fast to new areas and the efforts made to curtail it have proved inadequate.

Domestic ducks have now become a “reservoir” for the virus. They are acting like a carrier for the virus – their bodies carry the virus without showing signs of any infection. Infected ducks then release large quantities of the virus in pathogenic form in their excretions spreading the virus to other birds or humans. This has made detection of the virus difficult especially in rural areas.

According to health experts, the virus has already met the first two prerequisites for starting a pandemic. First it has attained a form, for which humans have no inbuilt immunity; and second, it has proved pathogenic enough to cause serious illness and death in humans.

The present risk of a pandemic is very high. The only factor that has prevented a pandemic so far is that the virus has not mutated into a form that would allow it to transmit efficiently from one human to another. Once such a genetic change takes place for the virus, a pandemic will be inevitable. The first signs of such a reassortment will be presence of the clusters of patients with flu symptoms, closely related – both in time and space. This would be a clear indication of virus having the ability to transmit from human-to-human.

Currently no vaccine has been developed for fighting H5N1 strain. Simultaneous work is being done in many countries for developing a vaccine, but no success has been achieved. The exact virus that may cause the pandemic cannot be predetermined. Thus mass production of vaccine before the pandemic starts is ruled out. The worldwide manufacturing capacity is inadequate to match the sudden demand surge during a pandemic. The best that scientists can do is to carry out a study and determine the smallest amount of antigen per dose that will provide sufficient protection and thus maximise the number of vaccines produced.

What Are The Precautions Necessary To Prevent A Pandemic?

The logical first step is to control the disease from spreading among birds, but this seems a difficult task now. Bird Flu has become a bird epidemic in many parts of Asia and is spreading fast.

The Next step is to prevent the disease from getting passed on to humans. People who come in close contact with birds (like poultry farmers) are advised to keep a close watch on the health of birds, notify any sort of sickness in birds to the health authorities and avoid direct contact with sick birds in all cases. (Ducks have become a reservoir for the virus and may not exhibit signs of sickness even if they are carrying the virus.)

In case the flu becomes a pandemic, most countries of the world will be affected. In such a scenario, the best preventive measures would be personal hygiene, avoiding crowded places and staying away from raw meat and eggs.

A flu shot does not prevent bird flu, but it can protect a person from other forms of flu and avoid complications. Persons above 65 years of age, children, health services workers, people with chronic respiratory disorders, travellers to flu affected countries and pregnant women may consult a doctor regarding flu vaccination.

What Are The Symptoms In Humans and Treatment Options For Bird Flu?

A person infected by bird flu may have all symptoms of common flu like fever, persistent cough, sore throat and body ache. Moreover, there is a high risk of complications such as pneumonia, bronchitis, eye and ear infections and severe breathing problems.

Presently four drugs are used to combat influenza.

The most effective drugs known for seasonal flu are Oseltamivir (commercial name Tamiflu) and Zanamavir (Commercial name Relenza). Both of these are known to reduce severity and duration of seasonal flu, but they may prove ineffective if the virus is allowed to stay in the body for too long. Health professionals advise that TREATMENT OF FLU WITH THESE DRUGS SHOULD START WITHIN 48 HOURS OF FIRST APPEARANCE FLU SYMPTOMS.

Oseltamivir and Zanamavir fall in the Neuraminidase inhibitors class. The surface protein Neuraminidase breaks bonds between new viruses and infected cells. By blocking the activity of Neuraminidase, these two drugs prevent the new viruses from being released.

Another class of drugs – the M2 inhibitors is also available, but viruses develop resistance to these drugs quickly and thus these drugs may prove ineffective in controlling pandemics. Amantadine and Rimantadine are two drugs from this class. These drugs inhibit the activity of M2 protein, which forms a channel in membranes of viruses and thereby preventing the viruses from replicating.

One should consult a doctor before taking any of these drugs as THESE DRUGS ARE KNOWN TO HAVE SIDE EFFECTS IN SOME CASES. For example, Zanamavir is not recommended to people having chronic respiratory diseases such as asthma.

(This article was written on 25th January 2006 and may not contain developments that took place after this date.)

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