Posted on 10/26/2007 6:43:06 PM PDT by blam
Bird Flu Finds Children's Lungs Faster
ScienceDaily (Oct. 27, 2007) — New findings, reported in the journal Respiratory Research, about how the virus binds to the respiratory tract and lung suggest children may be particularly susceptible to avian influenza,. The results also mean that previous receptor distribution studies may have to be re-evaluated.
Pediatric tissue sample. The researchers found that a particular form of MAA (MAA1) displayed widespread binding throughout the respiratory tract, but was particularly good at binding to children's cells in the lower respiratory tract. (Credit: Image courtesy of BioMed Central)"
John Nicholls and colleagues at the University of Hong Kong and Adelaide Women and Children's Hospital, in Australia, describe a modified technique to visualize the putative receptors for influenza viruses in the upper and lower respiratory tract, including the lung.
Sialic acid molecules on the cell surface act as chemical beacons for the influenza virus. Once the virus finds sialic acid, it can attach and infect the cell, although the precise distribution of sialic acid molecules affects how easily the virus can find host cells to infect.
The team has turned to lectins- molecules which bind sugars, to help them differentiate receptors for human and avian influenza viruses. The researchers used an improved staining technique to see how well two lectins, Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA), bind to different forms of sialic acid on respiratory tract cells in healthy adults and children. SNA is particularly good at identifying the receptor for human influenza viruses while MAA identifies the receptor for avian viruses - including H5N1.
The researchers found that a particular form of MAA (MAA1) displayed widespread binding throughout the respiratory tract, but was particularly good at binding to children's cells in the lower respiratory tract as well as the upper respiratory tract of adults. Although this MAA1 binding is not unique for avian influenza receptors, these findings could explain how avian influenza infects children more readily than it does adults. This may explain previous findings from this group that avian H5N1 viruses can infect the human upper respiratory tract, even though these tissues were thought to lack receptors for these viruses.
"Understanding the how and why of avian virus infection of humans is a very complex process involving research into properties of H5N1 virus, the host receptor and the cellular response" said Dr John Nicholls. "We believe that the studies we have done investigating where the receptors are located and their distribution with age is a small step towards unravelling this process and help in finding ways to diminish the potential treat from this emerging infection."
Article: John M Nicholls, Anthony J Bourne, Honglin Chen, Yi Guan and J S Malik Peiris, Sialic acid receptor detection in the human respiratory tract: evidence for widespread distribution of potential binding sites for human and avian influenza viruses, Respiratory Research (in press)
Adapted from materials provided by BioMed Central.
BF Ping.
Oddly, the Spanish Flu tended to hit those in their early twenties to thirties very hard. Older children and those in their teens were relatively less affected. Very strange pattern for a disease.
Ping... (Thanks, blam!)
The response is more likely in those with the most well-developed and healthy immune systems, precisely the late teen to thirty-something age group.
Minerals from French Clay Cure Deadly Drug-Resistant Bacteria
By Shan Juan (China Daily)
Updated: 2007-10-27 08:54
Pregnant women infected with the H5N1 bird-flu virus can pass the deadly disease to their unborn babies, a study by Chinese experts has found.
But the discovery does not mean a global pandemic is at hand, Gu Jiang, director of the School of Basic Medical Sciences affiliated to Peking University, which led the study, said.
"So far, no substantiated case of interhuman transmission has been observed," Gu said. "It largely depends on how the virus further mutates."
Gregory Hartl, a spokesman for the World Health Organization, said the passing of the virus from mother to fetus was not really a case of human-to-human transmission as the two effectively function as a single body.
By studying tissues taken from the body of a 24-year-old pregnant woman killed by bird flu, Gu discovered the virus had passed through her placenta to infect the fetus.
Gu said his research project, which also involved studying tissue from a 35-year-old man killed by the virus, was the eighth of its kind worldwide.
He said that as well as being found in the woman's placenta, the virus was detected in the alimentary canal, brain, blood cells and respiratory tract of both victims. It was also found in the lungs and liver of the fetus.
The findings have great significance for treatment and prevention, Gu said.
"For example, blood and feces from people infected with the virus must be handled extremely carefully to avoid further spreading of the disease."
Earlier today I read that the 3 -D the configuration of the genetic complex of H5N1 actually looks more like the 1918 virus. Our immune systems have no experience with H5 glycoprotein subtype which means we are up the creek when this reassorts or recombinds in swine or any mammal. If you want a good intro to understanding the receptor binding site details in H5N1:
http://www.fluwiki.com/pmwiki.php?n=Science.InfluenzaPrimerII
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