How does a new virus spread? Monitoring of the ‘bird flu’ virus (Influenza A H5N1) which emerged in domesticated poultry in China during 2003 found that many of the transmissions followed major transport routes, so were due to human activity. Since the virus can cross into humans and has a high mortality rate (59%), containment was crucial to prevent further infection. Methods used included culling infected flocks, closing poultry markets in high-risk areas and decontamination sprays in those markets that remained open (pictured). Today, ten years on, a double threat exists: another human-infecting strain of bird flu (H7N9) was detected earlier this year; meanwhile the original H5N1 strain is moving via migratory birds, such as ducks, making containment difficult. Researchers agree that eventually bird flu will spread in human populations globally (a pandemic); so they are working to develop large-scale vaccines to protect against as many viral strains as possible.
Written by Julie Webb
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