Genetic variants of influenza A (H1N1) pdm09 virus circulating in Kenya, 2010 to 2011

Mukunzi S, Bulimo W, Achilla R, Wadegu M, Majanja J, Opot B, Osuna F, Muthoni J, Njiri J, Mwangi J, Kibet K, Ochola S, Wurapa E. "Genetic variants of influenza A (H1N1) pdm09 virus circulating in Kenya, 2010 to 2011.". In: Options for the control of influenza VII. Capetown, South Africa; 2013.

Date Presented:

5-10 September 2


Background: Since the emergence followed by rapid global spread to cause the 2009 pandemic, influenza A (H1N1)pdm09 viruses remained predominant among human influenza viruses that circulated in Kenya during the 2010-2011 season. In this study we sought to determine genetic variation amongst influenza A (H1N1) pdm09 viruses isolated in Kenya during the postpandemic period with reference to prototype influenza A/California/7/2009 strain and others obtained elsewhere during the same period. Materials and Methods: A total of 30 influenza A (H1N1) pdm09 isolates obtained from nasopharyngeal specimens (NP) and received from USAMRU-K’s sentinel surveillance network covering the whole of Kenya were analyzed. Virus HA1 subunit of hemagglutinin gene segment was amplified by RT-PCR and nucleotide sequences determined followed by conversion of the sequences to amino acid code before performing phylogenetic analyses. Results: The study showed all Kenyan isolates had 6 parallel amino acid substitutions when compared with the prototype A/California/07/2009 vaccine reference strain. These included P83S, D97N, S185T, S203T, I321V, and E374K. Additionally, there were further mutations that occurred stochastically in individual isolates. Most of these changes, however, did not affect virus antigenic sites; except the P83S amino acid substitution at site Cb and a few other changes at sites Ca1, Sa, and Sb in individual isolates.



UoN Websites Search