all over the map. influenza virus strains come together in 11 groups on the new antigenic map. The letters refer to the location (Hong Kong, England, Victoria, Texas, Bangkok, Suchan, Beijing, Wuhan, Sydney, and Fujian) and numbers to the year of isolation.
Like devotees mode, influenza viruses change their appearance every year. Mutations in using viral surface of the virus outside the human immune system, resulting in annual epidemics. Now researchers have developed a mathematical tool to analyze and visualize this "antigenic drift". The study, applicable to other viruses as well, can help make the annual selection of the best vaccine easiest flu.
The study focused on H3N2, a strain of flu that first afflicted man in 1968. To keep track of its evolutionary tricks, researchers worldwide commonly infect animals with new H3N2 strains, the antiserum harvest, and test how the antiserum neutralizes other known varieties of H3N2. When antiserum triggered by a strain neutralizes another strain, both are presumed to be near, and those exposed to a virus can expect to be free of the other; if a bad game, both strains are more remote. But lack a visual representation, the vast collection of "tables, rows and numbers" was difficult to manage, says Richard Webby flu researcher Research Hospital St. Jude Children in Memphis, Tennessee.
A map was needed, says computer scientist Derek Smith of the Erasmus University Rotterdam (EUR), the Netherlands. Like the remote table in the back of a road atlas can be used to generate a rough map of a country, the "distance" between viruses gleaned from antisera tests can be used to draw on each strain a map. In a study published online this week by Science , Smith and colleagues - including EUR virologist Ron Fouchier and physicist Alan Los Alamos National Laboratory Lapedes New Mexico - make such a map, based on data dating back to 1968. It shows that the virus is moving gradually in a series of 11 closely related virus groups to escape human immunity.
to test the reliability of the card, the team predicts how antisera strains, virus that has never been matched before would match, depending on the distance between them on the map, and then performed the test laboratory to check their prediction. They found that the predictions were unreliable.
"This gives me comfort that what they do is real," says Webby. Being able to visualize antigenic drift and make predictions about how the serum against one strain protects against another should also help stem the annual process of selection for the vaccine against the flu, he said.
related site
the site of the flu by the World health Organization
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