Distribution of ILI cases, seasonal and Influenza A(H1N1)pdm09 positives by age groups in urban population from July 2009–December 2010.

<p>Distribution of ILI cases, seasonal and Influenza A(H1N1)pdm09 positives by age groups in urban population from July 2009–December 2010.</p

Comparative analysis of circulating influenza viruses (Influenza A and B) among children <18 years of age in urban (purple) and peri-urban (orange) setting from July-December 2009 (left panel) and January-December 2010 (right panel).

<p>Comparative analysis of circulating influenza viruses (Influenza A and B) among children <18 years of age in urban (purple) and peri-urban (orange) setting from July-December 2009 (left panel) and January-December 2010 (right panel).</p

Monthly trends and seasonality of circulating seasonal and pandemic influenza viruses in urban (Panel A) and peri-urban (Panel B) area from 2007–2010.

<p>The left axis shows monthly percent positivity. The overall % positivity of types and subtypes is shown as bar graph for urban (Top) and peri-urban (bottom) area from 2007 to 2010.</p

Surveillance for Influenza-like-Illness in and around Delhi, North India, 2007–2010.

<p>*Denominator for the percentage is # influenza positive for that year.</p

Phylogenetic analysis of HA gene of Influenza A(H1N1)pdm09 strains isolated from Urban (blue) and peri-urban (green) sites from Delhi region, North India in Aug 2009 or 2010.

<p>The representative strains from 2009/A/California(H1N1) strain and from other parts of the world and India (Orange) were used to generate the phylogenetic tree. The characteristic amino acids unique to clade 7 (S203T) is shown at the root of the branch.</p