Evolution trends of the 2009 pandemic influenza A (H1N1) viruses in different continents from March 2009 to April 2012

Abstract

The World Health Organization (WHO) announced that the 2009 pandemic influenza A (H1N1) viruses, A/California/07/2009 (H1N1) — like virus, has gone into the post-pandemic period on August 10, 2010. People still have some concerns the virus would likely mutate and become a new pandemic virus in the future. Here, we use MUSCLE program and graphic mapping method to look into the evolutionary characteristics of the 6219 hemagglutinin and 4860 neuraminidase full-length sequences from March 2009 to April 2012. The graphic and statistical analyses showed that the novel pandemic isolates, A/California/07/2009 (H1N1) — like virus, experienced several different times. During the early-pandemic period (03/2009-08/2009), the viruses have spread globally in several clusters and deviated slightly from the recommended vaccine strain, A/California/07/2009. During the pandemic period (09/2009-08/2010), new clusters began to emerge from Asia and North America, and further deviated from the recommended vaccine strain. During the postpandemic period (09/2010-08/2011) and the recent period (09/2011-04/2012), the original cluster with the recommended vaccine isolate, A/California/07/2009, has nearly disappeared. The deviation degree between the new clusters and the vaccine isolate became larger and larger. However, the deviation degree and the deviation speed were low. The WHO did not choose a new vaccine isolate instead of the original vaccine isolate, A/California/07/2009. Even so, it is necessary to monitor continuously the 2009 pandemic influenza A (H1N1) viruses.

Protein Sequence Comparison Method Based on 3-ary Huffman Coding

“…The strain became the recommended vaccine strain for H1N1 virus in the following years. The results are also consistent with the works [44,48].…”

Novel Method of 3-Dimensional Graphical Representation for Proteins and Its Application

“…This illustrates that there are 2 different kinds of influenza A (H1N1) virus isolates from March 1, 2009 to April 30, 2009. This result is consistent with the works by Qi et al 14,28 Furthermore, the result is also consistent with the biology fact that a new influenza virus, A/California/07/2009 (H1N1)-like virus, appeared and showed a strong ability to infect human beings in April 2009. 23 The branch length in Figure 3 is the similarity distance between 2 virus isolates.…”

Evolution analysis for HA gene of human influenza A H3N2 virus (1990 – 2013)

“…PCA is such a solution in multivariate statistical method. Now, Principal components analysis (PCA) and its many expanded methods have been successfully applied to the resolution of many biological problems [7][8][9]. PCA is a projection method to analyze data set [10].…”