| As more and more cases of bird flu are reported, the | | | | sure that no part of the meat remains raw or |
| world faces an immediate threat of a deadly | | | | uncooked.How Big Is The Risk Of A Pandemic |
| pandemic. Pandemics (Global Disease Outbreaks) are | | | | Breaking Out?The world had to face a Bird Flu |
| known to be like flash floods. They start abruptly, | | | | Pandemic, thrice in the twentieth century. In 1918-1919, |
| spread fast and cause a lot of damage all over the | | | | "Spanish Flu" killed anywhere between 20 million to 50 |
| world.A few facts that everyone should know:What is | | | | million people (exact figures not known), including half a |
| Avian Influenza? As the name suggests, avian | | | | million in the United States alone. The "Asian flu" in |
| influenza refers to the infection caused by avian (bird) | | | | 1957-58 killed 70,000 in the United States and in |
| influenza (flu) viruses. These viruses are commonly | | | | 1968-1969, the "Hong Kong flu" killed 34,000 in the |
| found in intestines of wild birds and these birds can | | | | USA.Currently the risk of H5N1 strain leading to a |
| carry the viruses without getting sick. However the | | | | Pandemic is high. The virus is spreading fast to new |
| viruses can be pathogenic to domesticated birds like | | | | areas and the efforts made to curtail it have proved |
| chickens, ducks and turkeys. Domesticated birds | | | | inadequate.Domestic ducks have now become a |
| become infected through exposure to other birds or | | | | "reservoir" for the virus. They are acting like a carrier |
| through surfaces contaminated by secretions and | | | | for the virus - their bodies carry the virus without |
| faeces of the infected birds.These viruses are | | | | showing signs of any infection. Infected ducks then |
| classified as Low Pathogenicity and High Pathogenicity. | | | | release large quantities of the virus in pathogenic form |
| Most strains of Avian Influenza come under Low | | | | in their excretions spreading the virus to other birds or |
| Pathogenicity Avian Influenza (LPAI) Group and | | | | humans. This has made detection of the virus difficult |
| produce mild symptoms in the infected birds. Common | | | | especially in rural areas.According to health experts, |
| symptoms are ruffled feathers, decreased food | | | | the virus has already met the first two prerequisites |
| appetite, decreased egg production, sneezing and | | | | for starting a pandemic. First it has attained a form, for |
| coughing. Many times LPAI may go undetected.High | | | | which humans have no inbuilt immunity; and second, it |
| Pathogenicity Avian Influenza (HPAI) has more severe | | | | has proved pathogenic enough to cause serious illness |
| symptoms which include sudden death, loss of energy | | | | and death in humans.The present risk of a pandemic is |
| and appetite, decreased egg production, respiratory | | | | very high. The only factor that has prevented a |
| problems, facial oedema (swelling), poorly formed eggs | | | | pandemic so far is that the virus has not mutated into |
| and diarrhoea. HPAI can reach a mortality rate of | | | | a form that would allow it to transmit efficiently from |
| nearly 100%.What Is H5N1 strain of Bird Flu?All flu | | | | one human to another. Once such a genetic change |
| viruses are classified as type A, B or C depending on | | | | takes place for the virus, a pandemic will be inevitable. |
| their structural arrangement. Type A is responsible for | | | | The first signs of such a reassortment will be |
| lethal pandemics and is found in both animals and | | | | presence of the clusters of patients with flu |
| humans. Type B causes local outbreaks of flu. Type C | | | | symptoms, closely related - both in time and space. |
| is the most stable of the three and infected people | | | | This would be a clear indication of virus having the |
| show only mild symptoms of flu. Type B and C are | | | | ability to transmit from human-to-human.Currently no |
| usually found only in humans. Type B and C are more | | | | vaccine has been developed for fighting H5N1 strain. |
| stable than type A and are not classified according to | | | | Simultaneous work is being done in many countries for |
| their subtypes.Influenza viruses of type A are divided | | | | developing a vaccine, but no success has been |
| into subtypes and the naming is done on the basis of | | | | achieved. The exact virus that may cause the |
| two proteins (antigens) found on their surface - | | | | pandemic cannot be predetermined. Thus mass |
| Hemagglutinin (HA) and Neuraminidase (NA). Sixteen | | | | production of vaccine before the pandemic starts is |
| types of HA and nine types of NA exist. Thus a total | | | | ruled out. The worldwide manufacturing capacity is |
| 144 combinations are possible.Thus H5N1 is a type A | | | | inadequate to match the sudden demand surge during |
| virus and gets its name from HA 5 protein and NA 1 | | | | a pandemic. The best that scientists can do is to carry |
| protein present on its surface.How Do Type A Viruses | | | | out a study and determine the smallest amount of |
| Cause A Pandemic?Type A viruses are further | | | | antigen per dose that will provide sufficient protection |
| classified into strains. These strains can continuously | | | | and thus maximise the number of vaccines |
| evolve into different strains. Their ability to exchange | | | | produced.What Are The Precautions Necessary To |
| genetic material with other viruses and create new | | | | Prevent A Pandemic?The logical first step is to control |
| influenza viruses makes them unpredictable and | | | | the disease from spreading among birds, but this |
| difficult to fight with. Humans have to develop new | | | | seems a difficult task now. Bird Flu has become a bird |
| immunity (antibodies) every time new strains are | | | | epidemic in many parts of Asia and is spreading |
| created.Viruses cannot repair genetic damage, small | | | | fast.The Next step is to prevent the disease from |
| changes known as "Antigen Drift", are continuously | | | | getting passed on to humans. People who come in |
| creating new strains of viruses. However when | | | | close contact with birds (like poultry farmers) are |
| genetic material from Type A viruses from different | | | | advised to keep a close watch on the health of birds, |
| species - say a bird and a human, comes together and | | | | notify any sort of sickness in birds to the health |
| merges, an entirely new strain is created. This is | | | | authorities and avoid direct contact with sick birds in all |
| known as "Antigen Shift" Humans have no immunity to | | | | cases. (Ducks have become a reservoir for the virus |
| such a strain and the strain can spread rapidly causing | | | | and may not exhibit signs of sickness even if they are |
| a Pandemic.How Is The Virus Transmitted To Humans | | | | carrying the virus.)In case the flu becomes a pandemic, |
| From Birds?Usually Avian Influenza viruses do not | | | | most countries of the world will be affected. In such a |
| infect humans. Migratory birds act as carriers of these | | | | scenario, the best preventive measures would be |
| viruses and do not get affected by them. These birds | | | | personal hygiene, avoiding crowded places and staying |
| then come in contact with domesticated birds such as | | | | away from raw meat and eggs.A flu shot does not |
| chickens and turkeys and spread the infection to them. | | | | prevent bird flu, but it can protect a person from other |
| Domesticated birds may get the virus from contact | | | | forms of flu and avoid complications. Persons above |
| with contaminated surfaces too. Once a virus infects | | | | 65 years of age, children, health services workers, |
| domesticated birds, it can cause severe epidemic | | | | people with chronic respiratory disorders, travellers to |
| among the birds. Humans come in contact with | | | | flu affected countries and pregnant women may |
| infected birds or contaminated surfaces and pick up | | | | consult a doctor regarding flu vaccination.What Are |
| the virus.In the human body, this avian flu virus then | | | | The Symptoms In Humans and Treatment Options For |
| undergoes an antigenic shift, combines with genetic | | | | Bird Flu?A person infected by bird flu may have all |
| material of a human strain of influenza virus and | | | | symptoms of common flu like fever, persistent cough, |
| creates an entirely new strain of virus against which | | | | sore throat and body ache. Moreover, there is a high |
| humans have little or no immunity. These genetic | | | | risk of complications such as pneumonia, bronchitis, eye |
| reassortments may also take place is the body of a | | | | and ear infections and severe breathing |
| third species (susceptible to both avian and human | | | | problems.Presently four drugs are used to combat |
| viruses) like the pig, where an avian influenza A virus | | | | influenza.The most effective drugs known for |
| and human influenza virus mix their genetic information | | | | seasonal flu are Oseltamivir (commercial name |
| and produce a new virus which might be able to infect | | | | Tamiflu) and Zanamavir (Commercial name Relenza). |
| humans.Why is H5N1 dangerous?The first reported | | | | Both of these are known to reduce severity and |
| cases of H5N1 infections were detected in geese in | | | | duration of seasonal flu, but they may prove |
| 1997 in Southern China. A total of 18 human infections | | | | ineffective if the virus is allowed to stay in the body for |
| were reported and six of them succumbed to it. The | | | | too long. Health professionals advise that |
| infection spread quickly to poultry in Hong Kong. At | | | | TREATMENT OF FLU WITH THESE DRUGS |
| that time a million and half chickens were culled in Hong | | | | SHOULD START WITHIN 48 HOURS OF FIRST |
| Kong to keep the virus under control. The virus | | | | APPEARANCE FLU SYMPTOMS.Oseltamivir and |
| disappeared for a few years, but resurfaced in 2002 | | | | Zanamavir fall in the Neuraminidase inhibitors class. The |
| in Hong Kong again. Since then it has killed millions of | | | | surface protein Neuraminidase breaks bonds between |
| birds in Asia and many cases of human infections | | | | new viruses and infected cells. By blocking the activity |
| have been reported.The persistence of this H5N1 strain | | | | of Neuraminidase, these two drugs prevent the new |
| of virus is a great concern for humans. Although the | | | | viruses from being released.Another class of drugs - |
| virus does not spread from birds to humans easily, the | | | | the M2 inhibitors is also available, but viruses develop |
| severity of the infection of H5N1 in humans is | | | | resistance to these drugs quickly and thus these drugs |
| frightening. The virus has killed every second person | | | | may prove ineffective in controlling pandemics. |
| infected by it. These cases were reported in perfectly | | | | Amantadine and Rimantadine are two drugs from this |
| healthy individuals who had no past history of | | | | class. These drugs inhibit the activity of M2 protein, |
| infections. However the greater concern for the world | | | | which forms a channel in membranes of viruses and |
| is the POSSIBILITY THAT THE VIRUS MAY | | | | thereby preventing the viruses from replicating.One |
| MUTATE (UNDERGO ANTIGENIC SHIFT) AND | | | | should consult a doctor before taking any of these |
| CREATE A FORM THAT MAY SPREAD FROM | | | | drugs as THESE DRUGS ARE KNOWN TO HAVE |
| HUMAN TO HUMAN. Such a strain of virus may result | | | | SIDE EFFECTS IN SOME CASES. For example, |
| in a pandemic, killing millions of people worldwide.Is | | | | Zanamavir is not recommended to people having |
| Consumption Of Poultry Birds Safe?Yes, it is safe to | | | | chronic respiratory diseases such as asthma.(This |
| consume THOROUGHLY COOKED poultry products. | | | | article was written on 25th January 2006 and may not |
| The H5N1 virus is sensitive to heat and gets destroyed | | | | contain developments that took place after this |
| by normal cooking temperatures of 70- 100 degree | | | | date.)Sachin A. is a Freelance Writer and specializes in |
| Celsius. If meat from poultry birds and eggs are | | | | articles that require extensive research. |
| cooked properly, the virus will be destroyed. Just make | | | | |