Major genetic differences was seen between the virus in its early and peak phase of infection in Japan. The genetic differences was revealed in an analysis of the 2009 pandemic influenza A (H1N1) virus. While yielding valuable clues on the genetic origins of drug resistance, the findings also pave the way toward the development of new diagnostic kits for detecting and preventing the spread of global pandemic diseases.
A unique triple combination of bird, swine and human flu viruses, the pandemic influenza A(H1N1) virus, first detected in April of 2009, quickly spread from Mexico to locations across the world. By April 2010, outbreaks of the disease at both local and global scales had resulted in roughly 18,000 deaths worldwide, causing serious damage both to human health and on the global economy.
In Japan, the first case of the pandemic was reported on May 9, 2009, thereafter spreading to hundreds of people in Osaka and Kobe and eventually leading to more than 200 deaths in the country. Existing research on the spread of the virus in Japan has provided valuable information on local strains during the early phase of infection and on their classification into different groups. How the pandemic evolved to reach its peak phase of contagion, however, is not yet well understood.