Certain strains of Bird Flu have been detected in the poultry farms in Southern Pakistan. H5N1 strain has been identified in a family in Karachi. The news has brought back the fear and scare in the minds of the ordinary people who consume poultry meat regularly. The news has also affected the poultry business by bringing down the sales and damages to the poultry crops in the poultry farms.
There is a lot of confusion about bird flu in the common man. Little information is shared by the official channels and people are, largely, unaware of the precautions they need to take when such outbreaks of bird flu occur in the area. The results are often chaotic and the resulting confusion adds to the management problems that the officials have to face, while handling such situations.
In the following posts i will try to talk about bird flu from both medical perspective and common man's perspective but mostly concentrate on enlightening the common man.
So, bird flu or avian influenza as it is known is a disease of the birds that is caused by a virus from a genus of viruses called Orthomyxoviridie. They are named according to their type, location where isolated , the successive isolate number from that location and year of isolation (eg, A/Karachi/5/08 [H5N1]). There are three recognized types of human influenza viruses, A, B and C. Only A and B cause major outbreaks of influenza. The viruses found in the poultry are similar to those that affect humans and sometimes the same.
Influenza has afflicted human beings throughout history. Three pandemics (outbreak on international level) occured in the last century: in 1918-1919, in 1957 and in 1968-1969. These pandemics occur at some interval because after one pandemic human beings develop immunity to the specific strain. It takes the virus another 40 to 50 years to undergo antigenic change (shift and drift) to be again able to infect humans again. There is all this fuss about influenza pandemic these days because scientists think that influenza has undergone sufficient antigenic shift to be able to infect humans at a large scale. For this shift to occur viruses need to live in vector hosts. Most of the times these hosts are either poultry or swine. Influenza viruses have evolved in an avian host and aquatic birds are now the major reservoir of influenza A virus. In these aquatic birds these viruses are carried asymptomatically most of the time but some strains produce disease.
Te disease in the birds is similar to that seen in humans. Most strains only infect and show disease in the respiratory system. But H5/N1 strain has a multi organ pathology and leads to disease that extends beyond respiratory system.
The transmission of the virus from its bird hosts to humans seems to occur through two routes. It ocurs both by respiratory aerosol inhalation and by direct contact with virus contaminated surfaces. Transmission in families has not been confirmed although there are rare reports of this being a possibility. Also the virus strain has to develop further to be affectively able to have human to human transmission.
During the past few years more than 340 patients have been identified and the mortality approaching 60%. The median age of patients has been 18 years and 90% of the patients falling in the less than 40 year age bracket. the mortality is higher in 10 to 19 year patient bracket.
In conclusion an Influenza pandemic is due and can happen with any of the possible strians of virus floating in the epizootic. H5/N1 and 7 strains cause severe disease in the poultry and cause multi organ failure in humans.
In the next posts i will deal with different aspects of the disease one by one.
Technorati Tags: bird flu, influenza, H5N1, pakistan, medicine
There is a lot of confusion about bird flu in the common man. Little information is shared by the official channels and people are, largely, unaware of the precautions they need to take when such outbreaks of bird flu occur in the area. The results are often chaotic and the resulting confusion adds to the management problems that the officials have to face, while handling such situations.
In the following posts i will try to talk about bird flu from both medical perspective and common man's perspective but mostly concentrate on enlightening the common man.
So, bird flu or avian influenza as it is known is a disease of the birds that is caused by a virus from a genus of viruses called Orthomyxoviridie. They are named according to their type, location where isolated , the successive isolate number from that location and year of isolation (eg, A/Karachi/5/08 [H5N1]). There are three recognized types of human influenza viruses, A, B and C. Only A and B cause major outbreaks of influenza. The viruses found in the poultry are similar to those that affect humans and sometimes the same.
Influenza has afflicted human beings throughout history. Three pandemics (outbreak on international level) occured in the last century: in 1918-1919, in 1957 and in 1968-1969. These pandemics occur at some interval because after one pandemic human beings develop immunity to the specific strain. It takes the virus another 40 to 50 years to undergo antigenic change (shift and drift) to be again able to infect humans again. There is all this fuss about influenza pandemic these days because scientists think that influenza has undergone sufficient antigenic shift to be able to infect humans at a large scale. For this shift to occur viruses need to live in vector hosts. Most of the times these hosts are either poultry or swine. Influenza viruses have evolved in an avian host and aquatic birds are now the major reservoir of influenza A virus. In these aquatic birds these viruses are carried asymptomatically most of the time but some strains produce disease.
Te disease in the birds is similar to that seen in humans. Most strains only infect and show disease in the respiratory system. But H5/N1 strain has a multi organ pathology and leads to disease that extends beyond respiratory system.
The transmission of the virus from its bird hosts to humans seems to occur through two routes. It ocurs both by respiratory aerosol inhalation and by direct contact with virus contaminated surfaces. Transmission in families has not been confirmed although there are rare reports of this being a possibility. Also the virus strain has to develop further to be affectively able to have human to human transmission.
During the past few years more than 340 patients have been identified and the mortality approaching 60%. The median age of patients has been 18 years and 90% of the patients falling in the less than 40 year age bracket. the mortality is higher in 10 to 19 year patient bracket.
In conclusion an Influenza pandemic is due and can happen with any of the possible strians of virus floating in the epizootic. H5/N1 and 7 strains cause severe disease in the poultry and cause multi organ failure in humans.
In the next posts i will deal with different aspects of the disease one by one.
Technorati Tags: bird flu, influenza, H5N1, pakistan, medicine
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