The spread of A(H7N9) by migratory birds

 Influenza A(H7N9) is a novel infectious bird flu strain that burst on the world's stage at the beginning of April 2013. Since then at least 132 individuals have been infected and more than 35 have died. [1]

In an article entitled Taiwan faces challenges on the emerging avian influenza A (H7N9) virus in China [2], researchers from Taiwan raise concerns over this novel influenza virus because it is a low path avian influenza virus (LPAI) in birds. This means that it does not kill off its avian hosts and is more difficult to detect in domesticated poultry and wild birds. The researchers note that after the closing the live poultry markets in Shanghai on April 5, the number of human cases caused by A(H7N9) virus dramatically decreased in that province. They speculate that A(H7N9) virus may spread silently in poultry in China and eventually spread globally through the migration of wild birds. They include a graphic depicting the geographic relation of humans cases in eastern portion of the People's Republic of China with the East Asian–Australasian migratory bird flyway.












The researchers in Taiwan have a right to be concerned. The only confirmed case of influenza A(H7N9) outside the mainland of the People's Republic of China was a Taiwanese national who worked in Suzhou, Jiangsu, where he was infected before returning to Taiwan.


[1] http://www.who.int/influenza/human_animal_interface/influenza_h7n9/RiskAssessment_H7N9_07Jun13.pdf



[2] http://www.jfma-online.com/article/S0929-6646%2813%2900171-X/fulltext