PLoS ONE (Jan 2012)

Molecular epidemiology of influenza A(H1N1)pdm09 viruses from Pakistan in 2009-2010.

  • Uzma Bashir Aamir,
  • Nazish Badar,
  • Muhammad Rashid Mehmood,
  • Nadia Nisar,
  • Rana Muhammad Suleman,
  • Shehzad Shaukat,
  • Salman Sharif,
  • Jaleel Kamran,
  • Syed Sohail Zahoor Zaidi,
  • Birjees Mazher Kazi,
  • Larisa Gubareva,
  • Xiyan Xu,
  • Rebecca Garten,
  • Alexander Klimov

DOI
https://doi.org/10.1371/journal.pone.0041866
Journal volume & issue
Vol. 7, no. 8
p. e41866

Abstract

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BackgroundIn early 2009, a novel influenza A(H1N1) virus that emerged in Mexico and United States rapidly disseminated worldwide. The spread of this virus caused considerable morbidity with over 18000 recorded deaths. The new virus was found to be a reassortant containing gene segments from human, avian and swine influenza viruses.Methods/resultsThe first case of human infection with A(H1N1)pdm09 in Pakistan was detected on 18(th) June 2009. Since then, 262 laboratory-confirmed cases have been detected during various outbreaks with 29 deaths (as of 31(st) August 2010). The peak of the epidemic was observed in December with over 51% of total respiratory cases positive for influenza. Representative isolates from Pakistan viruses were sequenced and analyzed antigenically. Sequence analysis of genes coding for surface glycoproteins HA and NA showed high degree of high levels of sequence identity with corresponding genes of regional viruses circulating South East Asia. All tested viruses were sensitive to Oseltamivir in the Neuraminidase Inhibition assays.ConclusionsInfluenza A(H1N1)pdm09 viruses from Pakistan form a homogenous group of viruses. Their HA genes belong to clade 7 and show antigenic profile similar to the vaccine strain A/California/07/2009. These isolates do not show any amino acid changes indicative of high pathogenicity and virulence. It is imperative to continue monitoring of these viruses for identification of potential variants of high virulence or drug resistance.