Authorities in China have confirmed that a 26 year old female farmer has bird flu, the H5N1 virus strain (the more virulent one). This brings to eleven the number of human cases confirmed in China.
The woman is from the south-eastern province of Fujian. She became ill on January 10th and was hospitalized with pneumonia. She is still in hospital and is said to be an a 'stable condition'.
There have been no recent poultry outbreaks in the region where the woman lives.
So far, of the eleven human cases in China, seven patients have died. They (all human infection cases) came from the provinces of:
-- Anhui
-- Fujian
-- Guangxi
-- Jiangxi
-- Hunan
-- Liaoning
-- Sichuan
As sporadic cases continue to surface, this indicates that the virus is still circulating among birds in some parts of the country.
There have been 32 poultry outbreaks since May 2005, say agricultural authorities. Most of these took place during October-November 2005.
Since the beginning of this year there have been three reported poultry outbreaks in China:
-- Sichuan Province (3 January)
-- Guizhou Province (10 January)
-- Shanxi Province (8 February)
Human cases started in November, 2005.
Written by:
понедельник, 13 июня 2011 г.
воскресенье, 12 июня 2011 г.
Cell Barrier Shows Why Bird Flu Not So Easily Spread Among Humans
Although more than 100 people have been infected with the H5N1 avian influenza virus, mostly from close contact with infected poultry, the fact that the virus does not spread easily from its pioneering human hosts to other humans has been a biomedical puzzle.
Now, a study of cells in the human respiratory tract reveals a simple anatomical difference in the cells of the system that makes it difficult for the virus to jump from human to human.
The finding, reported (March, 2006) in the journal Nature, is important because it demonstrates a requisite characteristic for the virus to equip itself to easily infect humans, the key development required for the virus to assume pandemic proportions.
The new report, by a research group led by University of Wisconsin-Madison virologist Yoshihiro Kawaoka, describes experiments using tissue from humans that showed that only cells deep within the respiratory system have the surface molecule or receptor that is the key that permits the avian flu virus to enter a cell.
Flu viruses, like many other types of viruses, require access to the cells of their hosts to effectively reproduce. If they cannot enter a cell, they are unable to make infectious particles that infect other cells -- or other hosts.
"Our findings provide a rational explanation for why H5N1 viruses rarely infect and spread from human to human, although they can replicate efficiently in the lungs," the authors of the study write in the Nature report.
By looking at human tissues, Kawaoka's group noted that the cells in the upper portions of the respiratory system lacked the surface receptors that enable avian H5N1 virus to dock with the cell. Receptors are molecules on the surface of cells that act like a lock. A virus with a complementary binding molecule -- the key -- can use the surface receptor to gain access to the cell. Once inside, it can multiply and infect other cells.
"Deep in the respiratory system, (cell) receptors for avian viruses, including avian H5N1 viruses, are present," explains Kawaoka, who also holds an appointment at the University of Tokyo. "But these receptors are rare in the upper portion of the respiratory system. For the viruses to be transmitted efficiently, they have to multiply in the upper portion of the respiratory system so that they can be transmitted by coughing and sneezing."
The upshot of the new finding, says Kawaoka, a professor of pathobiological sciences at the UW-Madison School of Veterinary
Medicine, is that existing strains of bird flu must undergo key genetic changes to become the type of flu pathogen most feared by biomedical scientists.
"No one knows whether the virus will evolve into a pandemic strain, but flu viruses constantly change," Kawaoka says. "Certainly, multiple mutations need to be accumulated for the H5N1 virus to become a pandemic strain."
The finding suggests that scientists and public health agencies worldwide may have more time to prepare for an eventual pandemic of avian influenza. Periodically, animal forms of influenza such as bird flu evolve to become highly contagious human pathogens.
Most scientists agree a pandemic of avian influenza will occur at some time. The worst-case scenario would be a form of influenza similar to the strain of 1918 that killed between 30 million and 50 million people globally. The new work may also help scientists keep track of evolving strains of influenza and provide earlier warning of potential pandemics. For the H5N1 strain of flu virus to evolve to a pathogen easily transmissible from one human to another, changes need to occur in the virus' hemagglutinin surface protein -- a molecule embedded in the virus membrane -- to recognize human receptors, Kawaoka says.
"Mutations in the hemagglutinin for avian H5N1 viruses to recognize human receptors are needed for the virus to become a pandemic strain," Kawaoka explains.
Viruses isolated from humans infected with avian flu can thus be monitored in a way to provide more advance warning of a potential pandemic.
"Identification of H5N1 viruses with the ability to recognize human receptors would bring us one step closer to a pandemic strain," says Kawaoka. "Recognition of human receptors can serve as molecular markers for the pandemic potential of the isolates."
The new study was conducted in collaboration with Kyoko Shinya and Shinya Yamada of the University of Tokyo; Masahito Ebina of the Institute of Development, Aging and Cancer; Masao Ono of Tohoku University; and Noriyuki Kasai of the Institute for Animal Experimentation in Japan.
Terry Devitt, (608) 262-8282, trdevittwisc
Contact: Yoshihiro Kawaoka
kawaokaysvm.vetmed.wisc
University of Wisconsin-Madison
Now, a study of cells in the human respiratory tract reveals a simple anatomical difference in the cells of the system that makes it difficult for the virus to jump from human to human.
The finding, reported (March, 2006) in the journal Nature, is important because it demonstrates a requisite characteristic for the virus to equip itself to easily infect humans, the key development required for the virus to assume pandemic proportions.
The new report, by a research group led by University of Wisconsin-Madison virologist Yoshihiro Kawaoka, describes experiments using tissue from humans that showed that only cells deep within the respiratory system have the surface molecule or receptor that is the key that permits the avian flu virus to enter a cell.
Flu viruses, like many other types of viruses, require access to the cells of their hosts to effectively reproduce. If they cannot enter a cell, they are unable to make infectious particles that infect other cells -- or other hosts.
"Our findings provide a rational explanation for why H5N1 viruses rarely infect and spread from human to human, although they can replicate efficiently in the lungs," the authors of the study write in the Nature report.
By looking at human tissues, Kawaoka's group noted that the cells in the upper portions of the respiratory system lacked the surface receptors that enable avian H5N1 virus to dock with the cell. Receptors are molecules on the surface of cells that act like a lock. A virus with a complementary binding molecule -- the key -- can use the surface receptor to gain access to the cell. Once inside, it can multiply and infect other cells.
"Deep in the respiratory system, (cell) receptors for avian viruses, including avian H5N1 viruses, are present," explains Kawaoka, who also holds an appointment at the University of Tokyo. "But these receptors are rare in the upper portion of the respiratory system. For the viruses to be transmitted efficiently, they have to multiply in the upper portion of the respiratory system so that they can be transmitted by coughing and sneezing."
The upshot of the new finding, says Kawaoka, a professor of pathobiological sciences at the UW-Madison School of Veterinary
Medicine, is that existing strains of bird flu must undergo key genetic changes to become the type of flu pathogen most feared by biomedical scientists.
"No one knows whether the virus will evolve into a pandemic strain, but flu viruses constantly change," Kawaoka says. "Certainly, multiple mutations need to be accumulated for the H5N1 virus to become a pandemic strain."
The finding suggests that scientists and public health agencies worldwide may have more time to prepare for an eventual pandemic of avian influenza. Periodically, animal forms of influenza such as bird flu evolve to become highly contagious human pathogens.
Most scientists agree a pandemic of avian influenza will occur at some time. The worst-case scenario would be a form of influenza similar to the strain of 1918 that killed between 30 million and 50 million people globally. The new work may also help scientists keep track of evolving strains of influenza and provide earlier warning of potential pandemics. For the H5N1 strain of flu virus to evolve to a pathogen easily transmissible from one human to another, changes need to occur in the virus' hemagglutinin surface protein -- a molecule embedded in the virus membrane -- to recognize human receptors, Kawaoka says.
"Mutations in the hemagglutinin for avian H5N1 viruses to recognize human receptors are needed for the virus to become a pandemic strain," Kawaoka explains.
Viruses isolated from humans infected with avian flu can thus be monitored in a way to provide more advance warning of a potential pandemic.
"Identification of H5N1 viruses with the ability to recognize human receptors would bring us one step closer to a pandemic strain," says Kawaoka. "Recognition of human receptors can serve as molecular markers for the pandemic potential of the isolates."
The new study was conducted in collaboration with Kyoko Shinya and Shinya Yamada of the University of Tokyo; Masahito Ebina of the Institute of Development, Aging and Cancer; Masao Ono of Tohoku University; and Noriyuki Kasai of the Institute for Animal Experimentation in Japan.
Terry Devitt, (608) 262-8282, trdevittwisc
Contact: Yoshihiro Kawaoka
kawaokaysvm.vetmed.wisc
University of Wisconsin-Madison
суббота, 11 июня 2011 г.
Bird flu hits Japan
Bird flu, which is highly contagious and has been rapidly spreading in parts of Asia, has arrived in Japan, say officials.
6,000 chickens died in the western prefecture of Yamaguchi (in a farm). Officials have confirmed that these chickens died of avian influenza (bird flu).
Japanese officials say that it is the first case since 1997. Bird flu can be deadly to humans (the last human death in Japan was 1925).
According to officials, this bird flu is of the H5 virus strain. They also said that all chickens in the area (of Yamaguchi) will be slaughtered (and incinerated) and eggs from the region will be stopped (from sale).
The countries most badly affected by this current bird flu are Vietnam, Taiwan, South Korea (recently) and now Japan.
6,000 chickens died in the western prefecture of Yamaguchi (in a farm). Officials have confirmed that these chickens died of avian influenza (bird flu).
Japanese officials say that it is the first case since 1997. Bird flu can be deadly to humans (the last human death in Japan was 1925).
According to officials, this bird flu is of the H5 virus strain. They also said that all chickens in the area (of Yamaguchi) will be slaughtered (and incinerated) and eggs from the region will be stopped (from sale).
The countries most badly affected by this current bird flu are Vietnam, Taiwan, South Korea (recently) and now Japan.
пятница, 10 июня 2011 г.
Bird flu outbreak spreads in Thailand, under control in Vietnam and China
Officials say the latest bird flu (avian flu) outbreak is spreading in Thailand and is under control in China and Vietnam.
In Thailand the situation is worrying authorities as 15 of the country's 76 provinces have cases of infection.
There are suspected cases of the more dangerous strain of bird flu, H5N1 awaiting lab results in China. This more dangerous strain killed several Thai and Vietnamese humans during another outbreak earlier on this year.
The Thai stock market has taken a 1% fall as a direct result of the current outbreak. Thailand is one of the largest chicken exporters in the world. The present and recent outbreaks of bird flu are 'devastating' the industry.
Fortunately, this outbreak has seen no cases of humans getting ill.
Authorities in China and Vietnam say there have been no new cases of bird flu over the last few days - this could mean that it is now under control in those countries.
In Thailand the situation is worrying authorities as 15 of the country's 76 provinces have cases of infection.
There are suspected cases of the more dangerous strain of bird flu, H5N1 awaiting lab results in China. This more dangerous strain killed several Thai and Vietnamese humans during another outbreak earlier on this year.
The Thai stock market has taken a 1% fall as a direct result of the current outbreak. Thailand is one of the largest chicken exporters in the world. The present and recent outbreaks of bird flu are 'devastating' the industry.
Fortunately, this outbreak has seen no cases of humans getting ill.
Authorities in China and Vietnam say there have been no new cases of bird flu over the last few days - this could mean that it is now under control in those countries.
четверг, 9 июня 2011 г.
H7 Bird Flu Increasing Potential To Infect And Spread Among Humans Reports CDC
A type of avian flu that is common in birds and rarely caught by humans, the North American Avian H7 influenza virus, is acquiring transmission properties similar to human influenza, according to a new study by US researchers at the Centers for Disease Control and Prevention (CDC), based in
Atlanta.
The study is the work of lead author and CDC researcher Dr Jessica Belser, and colleagues, and is published in the Proceedings of the National
Academy of Sciences (PNAS).
Most cases of avian flu in humans come from contact with infected birds or objects they have contaminated. But viruses are constantly changing,
which is why scientists are always tracking them. Belser said she and her co-investigators found that some strains of North American avian influenza
A H7 virus have developed characteristics that could increase their potential to infect humans, and also spread amongst them.
Avian H7 viruses from both Eurasia and North America have caused outbreaks in poultry since 2002, wrote the researchers, and have been known to
infect humans in outbreaks in the The Netherlands, British Columbia, and the United Kingdom.
Most H7 infections in humans end up as self-limiting conjunctivitis, and spread among humans is very rare.
Influenza viruses infect humans by attaching themselves to sugar molecules that dock onto receptors on the surfaces of cells in the human body's
respiratory tract. The ability of a virus to do this varies from virus to virus. The ones that do it well are the ones that are most likely to spread from
human to human, for example through cough or sneeze droplets.
Belser and her co-researchers used glycan microarray technology to investigate the receptor-binding preference of Eurasian and North American
lineage H7 influenza viruses and their ability to spread in birds and also in ferrets, which, like mice, have similar inflluenza transmission properties to
humans.
The results showed that:
Highly pathogenic H7N7 viruses from The Netherlands in 2003 kept the classic avian receptor-binding preference and were not readily
transmissible in ferrets, as has been observed for highly pathogenic H5N1.
But H7N3 viruses isolated from Canada in 2004, and H7N2 isolated in 2002-2003 from the northeastern United States, showed a binding
preference for the receptor linkages found prominently on human tracheal epithelial cells.
A low pathogenic H7N2 virus isolated from a man in New York in 2003, A/NY/107/03, replicated efficiently in the upper respiratory tract of ferrets
and was capable of direct contact transmission in this species.
The authors concluded that:
"H7 influenza viruses from the North American lineage have acquired sialic acid-binding properties that more closely resemble those of human
influenza viruses and have the potential to spread to naГЇve animals."
In other words, in terms of its ability to gain a foothold in the upper respiratory tract and therefore spread to uninfected humans, the H7 bird flu virus
has changed to a form that more closely resembles the human flu virus itself.
Belser said that:
"The results of this study underscore the importance of continued influenza virus surveillance."
Although the H7 viruses are rarely dangerous to humans, studies like this are important because what happens in one strain can shed light on what happens in another strain. Experts believe it is only a matter of time before the much deadlier bird fllu virus, the H5N1, mutates into a human to human form.
"Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility."
Jessica A. Belser, Ola Blixt, Li-Mei Chen, Claudia Pappas, Taronna R. Maines, Neal Van Hoeven, Ruben Donis, Julia Busch, Ryan McBride, James
C. Paulson, Jacqueline M. Katz, and Terrence M. Tumpey.
PNAS, 2008 105: 7558-7563.
Published online on May 27, 2008.
DOI: 10.1073/pnas.0801259105
Click here for Abstract.
Source: CDC, PNAS.
Written by: Catharine Paddock, PhD
Atlanta.
The study is the work of lead author and CDC researcher Dr Jessica Belser, and colleagues, and is published in the Proceedings of the National
Academy of Sciences (PNAS).
Most cases of avian flu in humans come from contact with infected birds or objects they have contaminated. But viruses are constantly changing,
which is why scientists are always tracking them. Belser said she and her co-investigators found that some strains of North American avian influenza
A H7 virus have developed characteristics that could increase their potential to infect humans, and also spread amongst them.
Avian H7 viruses from both Eurasia and North America have caused outbreaks in poultry since 2002, wrote the researchers, and have been known to
infect humans in outbreaks in the The Netherlands, British Columbia, and the United Kingdom.
Most H7 infections in humans end up as self-limiting conjunctivitis, and spread among humans is very rare.
Influenza viruses infect humans by attaching themselves to sugar molecules that dock onto receptors on the surfaces of cells in the human body's
respiratory tract. The ability of a virus to do this varies from virus to virus. The ones that do it well are the ones that are most likely to spread from
human to human, for example through cough or sneeze droplets.
Belser and her co-researchers used glycan microarray technology to investigate the receptor-binding preference of Eurasian and North American
lineage H7 influenza viruses and their ability to spread in birds and also in ferrets, which, like mice, have similar inflluenza transmission properties to
humans.
The results showed that:
Highly pathogenic H7N7 viruses from The Netherlands in 2003 kept the classic avian receptor-binding preference and were not readily
transmissible in ferrets, as has been observed for highly pathogenic H5N1.
But H7N3 viruses isolated from Canada in 2004, and H7N2 isolated in 2002-2003 from the northeastern United States, showed a binding
preference for the receptor linkages found prominently on human tracheal epithelial cells.
A low pathogenic H7N2 virus isolated from a man in New York in 2003, A/NY/107/03, replicated efficiently in the upper respiratory tract of ferrets
and was capable of direct contact transmission in this species.
The authors concluded that:
"H7 influenza viruses from the North American lineage have acquired sialic acid-binding properties that more closely resemble those of human
influenza viruses and have the potential to spread to naГЇve animals."
In other words, in terms of its ability to gain a foothold in the upper respiratory tract and therefore spread to uninfected humans, the H7 bird flu virus
has changed to a form that more closely resembles the human flu virus itself.
Belser said that:
"The results of this study underscore the importance of continued influenza virus surveillance."
Although the H7 viruses are rarely dangerous to humans, studies like this are important because what happens in one strain can shed light on what happens in another strain. Experts believe it is only a matter of time before the much deadlier bird fllu virus, the H5N1, mutates into a human to human form.
"Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility."
Jessica A. Belser, Ola Blixt, Li-Mei Chen, Claudia Pappas, Taronna R. Maines, Neal Van Hoeven, Ruben Donis, Julia Busch, Ryan McBride, James
C. Paulson, Jacqueline M. Katz, and Terrence M. Tumpey.
PNAS, 2008 105: 7558-7563.
Published online on May 27, 2008.
DOI: 10.1073/pnas.0801259105
Click here for Abstract.
Source: CDC, PNAS.
Written by: Catharine Paddock, PhD
среда, 8 июня 2011 г.
Defra's Message On Avian Influenza
The UK's Department for Environment, Food and Rural Affairs (Defra) has issued a bulletin online in which it reiterates how infectious avian influenza (bird flu) is for birds and how badly it can affect commercial, wild and pet birds.
Defra added that the detection of the highly pathogenic H5N1 bird flu virus strain near Lyon, France, raises the probability that it will surface in the UK.
Defra is asking all keepers of any types of birds to maintain a high level of biosecurity to reduce the risk of introducing the disease. Everyone who keeps poultry or other domestic birds should remain vigilant for signs of the disease.
Deputy Chief Veterinary Officer Fred Landeg said:
"Early detection and slaughter of infected birds and dangerous contacts, and the imposition of movement controls around infected premises provide the most effective method of achieving this. We have eradicated previous outbreaks of avian influenza successfully in domestic birds using this method.
New information for organic poultry producers, on what happens if poultry are confined indoors to comply with official veterinary requirements, has been issued by Defra. Click Here (PDF).
More Avian Influenza Pages on Defra Web Site
Written by:
Defra added that the detection of the highly pathogenic H5N1 bird flu virus strain near Lyon, France, raises the probability that it will surface in the UK.
Defra is asking all keepers of any types of birds to maintain a high level of biosecurity to reduce the risk of introducing the disease. Everyone who keeps poultry or other domestic birds should remain vigilant for signs of the disease.
Deputy Chief Veterinary Officer Fred Landeg said:
"Early detection and slaughter of infected birds and dangerous contacts, and the imposition of movement controls around infected premises provide the most effective method of achieving this. We have eradicated previous outbreaks of avian influenza successfully in domestic birds using this method.
New information for organic poultry producers, on what happens if poultry are confined indoors to comply with official veterinary requirements, has been issued by Defra. Click Here (PDF).
More Avian Influenza Pages on Defra Web Site
Written by:
вторник, 7 июня 2011 г.
Indonesia Confirms 31st Human Case Of Bird Flu Infection
Indonesian authorities have confirmed the country's 31st human case of H5N1 bird flu infection. The patient worked in a poultry farm in West Java, which had had a bird flu outbreak before he started work there.
The man has made a full recovery. The Ministry of Health says he first developed bird flu like symptoms on the 20th March.
Of the 31 confirmed human cases of bird flu in Indonesia, 23 have died.
Bird Flu = Avian Flu
H5N1 is a bird flu virus strain. The most dangerous one for humans (the one everyone is worried about)
Written by:
The man has made a full recovery. The Ministry of Health says he first developed bird flu like symptoms on the 20th March.
Of the 31 confirmed human cases of bird flu in Indonesia, 23 have died.
Bird Flu = Avian Flu
H5N1 is a bird flu virus strain. The most dangerous one for humans (the one everyone is worried about)
Written by:
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