Department of Virology, Public Health Laboratories Division, National Institute of Health, Chak Shahzad, Islamabad, Pakistan.
PLoS One. 2012;7(8):e41866. doi: 10.1371/journal.pone.0041866. Epub 2012 Aug 20.
In 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/RESULTS: The 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.
Influenza 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.
2009 年初，一种新型甲型 H1N1 流感病毒在墨西哥和美国出现，并迅速在全球范围内传播。该病毒的传播导致了相当高的发病率，记录的死亡人数超过 18000 人。新病毒被发现是一种重组病毒，包含来自人流感、禽流感和猪流感病毒的基因片段。
方法/结果：2009 年 6 月 18 日，巴基斯坦首次检测到人类感染 A（H1N1）pdm09 病毒。此后，在各种疫情中检测到 262 例实验室确诊病例，死亡 29 例（截至 2010 年 8 月 31 日）。疫情高峰期出现在 12 月，超过 51%的呼吸道病例流感检测呈阳性。从巴基斯坦分离的病毒代表株进行了测序和抗原分析。编码表面糖蛋白 HA 和 NA 的基因序列分析显示，与东南亚地区流行的区域病毒相应基因具有高度的序列同一性。所有测试的病毒在神经氨酸酶抑制试验中对奥司他韦均敏感。
来自巴基斯坦的甲型 H1N1pdm09 病毒形成了一个同质的病毒群。它们的 HA 基因属于 7 谱系，具有与疫苗株 A/加利福尼亚/07/2009 相似的抗原表型。这些分离株没有显示任何氨基酸变化，表明其没有高致病性和高毒性。必须继续监测这些病毒，以确定是否存在高致病性或耐药性的潜在变异。
