Bird flu

Bird flu

Bird flu

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Bird flu

Can down and feathers transmit avian influenza?

Down- and feather-filled bedding articles do not carry any potential risk of transmitting avian influenza or bird flu. The spread of this disease is of no consequence for the use of the down- and feather-filled bedding.
 
There are two reasons for this:
  • The influenza virus needs a living host in order to be able to survive.
Down- and feather-filled bedding articles do not carry any potential risk of transmitting avian influenza or bird flu. The spread of this disease is of no consequence for the use of the down- and feather-filled bedding.
 
There are two reasons for this:
  • The influenza virus needs a living host in order to be able to survive. Down and feathers, however, are no such living host.
  • Before down and feathers are used as a filling for bedding, they are thoroughly washed and dried at a temperature of over 100° C or 212° F.

As all influenza viruses, the H5N1-virus belongs to the group of enveloped viruses. It is enclosed by a lipid envelope, or a mantle of fat. If this envelope is damaged, the virus loses its infective power. It is particularly sensitive to dryness and heat. It will neither survive long periods of dryness nor heat. This is why the virus cannot survive any treatment which is applied at temperatures above 100° C or 212° F.

The avian influenza is a highly contagious viral disease, which affects primarily chickens and turkeys, but also wild birds.
 
Actually, the terms “bird flu“, “avian flu” or “fowl plague” cover any sort of fowl infection brought about by avian influenza viruses. “Avian flu”, however, is caused in the true sense of the word only by avian influenza A viruses of the H5 or H7 subtypes. In our everyday language we mostly use all these terms as synonyms, though. The disease is also called “avian influenza”.
 
On the basis of their differing qualities we distinguish between influenza viruses of the A, B and C types. The type A virus is particularly dangerous, as this type of disease can become epidemic. Influenza viruses of the type A contain certain proteins, which go by the names of hemagglutinin and neuraminidase.
 
There are constantly emerging new types of influenza viruses. They are divided into subtypes.
The subtype of the avian influenza virus A/H5N1, for example, carries on its surface the fifth variation of the hemagglutinin (H5) and the first variation of the neuraminidase (N1). This virus strain, the H5N1, is a particularly aggressive variation, which causes 80 to 100 per cent of the affected animals to die.
 
Usually, these viruses affect humans very rarely, but if so, it mainly happens when they are in very close contact with fowl and when hygienic conditions are poor. A human-to-human transmission has occurred only in very few cases, after close unprotected contact with infected people had taken place.
 
As a consequence of changes in the genetic material of the virus, the speed of infection of humans could increase and, in particular, the disease could also be transmitted from person to person. This could happen if a virus acquires the capacity to attach itself to human cells by means of genetic variations. This is possible, particularly when the human influenza virus and the avian influenza virus meet in the same organism, and thus a double infection with avian and human influenza viruses takes place. If a person-to-person transmission actually occurred, a large scale epidemic, a so-called pandemic, could arise.
 
The Daunasan® / Downafresh® brand stands for carefully processed down and feathers.
 
The commercial processing of the filling material and the production of bedding articles are subject to strict regulations by the veterinary police, which have always been a benefit as much for the producers as for the consumers. Raw feathers and down may only be imported to Germany, if they are certified to be hygienically safe by the competent veterinary authorities.
 
It is, however, necessary to process the down and feathers before exporting them regardless of any hygiene regulations. Unprocessed, humid raw down and feathers would not endure undamaged the often long transit, for example from Asia. They would decompose after a short time and be unusable. This is one reason why it is necessary to dry down and feathers at high temperatures for a start. Furthermore, all pathogens and viruses are killed in this process.
Even if the virus survived the transport, i.e. in case the down and feathers were harvested in Germany and the transit period was a relatively short one, it would die off during the subsequent processing at the factory, where the raw down and feathers are washed several times and dried at temperatures above 100° C/212° F. Already heating the feathers to a temperature of 70° C /158° F for a time span of 10 minutes will definitely kill the pathogens – the higher the temperature, the faster they will die off. The lipid envelope of the virus will not survive such a treatment.

Johannes Bhakdi, professor at the Institute of Medical Microbiology and Hygiene at the Johannes Gutenberg University in Mainz considers the import ban on birds to be “still acceptable”, that on feathers, however, “completely crazy and beyond any scientific comprehension”. “The feathers have been washed and dried, and they have furthermore been in transit for several weeks before reaching this country. It is inconceivable, that a virus, which is covered by a lipid envelope – thus a mantle of fat –, will survive all of this“.



„Feathers do not cause avian influenza“
Microbiologist Sucharit Bhakdi from Mainz warns of hysteria / vaccination against influenza
09 August 2005 MAINZ
 
Avian influenza which has till now been diagnosed in Southeast Asia only, has now also reached Russia. We talked with Sucharit Bhakdi, Professor at the Johannes Gutenberg University in Mainz, Institute for Medical Microbiology and Hygiene, on potential dangers caused by the H5N1 virus.
 
Germany has meanwhile stopped imports of birds and feathers. Do you think these measures make sense?
Bhakdi:
It is understandable to put a ban on imports of birds. It is completely crazy and beyond all scientific finding, though, to ban imports of feathers. Leaving out the fact, however, that entire industries would get into economic difficulties, if imports of feathers from Asia were prohibited. These feathers were washed and dried – and moreover on transport for many weeks before they arrive here. It is inconceivable that a virus which is surrounded by a lipids case, i. e. a fat case, might outlive all these procedures.
 
How does avian influenza spread?
Bhakdi:
The viruses get into the body via the respiratory tract.
 
According to WHO sources, 57 people died by avian influenza globally. Under which circumstances does the illness pass over to human beings?
Bhakdi:
In fact, it has meanwhile been proved that the virus might pass over to human beings. This is indeed the reason for present hysteria which sometimes conveys the impression, as if the end of mankind was imminent. However, in very rare cases, the virus managed to pass over from one of 100.000 birds which have fallen ill to one human being. Actually, human beings are no appropriate hosts, otherwise there would have been many more infections. For the time being, an infection from man to man is even more improbable. This was only the case with three Thai people who lived together in very cramped surroundings.
 
What are many scientists worrying about then?
Bhakdi:
The virus would have to modify itself one more time in order to be transmitted efficiently from one human being to another. It just cannot be totally excluded that such a modification might happen. Let me try to explain it in a pictorial way. Influenza viruses have eight different kinds of proteins. Two of them are virtually the hands by means of which the virus docks, the other proteins virtually constitute the body which is partially responsible for specificity of the host (human being – bird). The “hands” of the avian virus are apparently in particular “evil”. If they dock a person, though the “body” does not fit to the human being, the virus is usually not able to propagate, and cannot “jump over” from one person to another. It becomes dangerous, if the human influenza virus and the avian influenza virus meet in the same living being. It might happen then that the viruses exchange their “hands”. A virus provided with avian influenza -“hands” could then propagate within the human body and also spread among human beings.
 
What kind of preventive measures could be taken then?
Bhakdi:
Usually, two simultaneous infections do not occur in human beings but more likely in pigs. Theoretically, the exchange of “hands” could also take place in human beings under the prerequisite that two infections occurred at the same time. This can be prevented by preventing an infection with the human virus – namely by vaccination against influenza.
 
Is vaccination available against avian influenza?
Bhakdi:
No, not at present. It causes problems to cultivate viruses for conventional serum production. From the genetically engineering point of view, however, it should be possible to prepare a serum.
 
What should people who travel to the concerned regions in Asia keep in mind?
Bhakdi:
The avian influenza virus has never jumped over to someone who simply “travelled” past. A rather close contact with birds would be necessary, instead. Which tourist would visit a poultry farm? Vaccination against influenza, however, is recommended in any case.
 
Das Interview führte Stefanie Widmann

 



Further information at the internet referring to bird flu

  • Prof. R. Braun, Labor Prof. Enders & Partner, Stuttgart (Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten e. V.): Geflügelgrippeviren: Wie ist die tatsächliche Bedrohung? www.edfa.eu
  • Einschätzung des Robert Koch-Instituts zur Situation der Vogelgrippe (aviäre Influenza), www.rki.de