Background Pakistan is 1 of the 2 countries endemic for wild poliovirus type 1 (WPV1). Active clinical and environmental wastewater surveillance along with laboratory investigation is an integral and primary component of polio eradication strategies. The current study is mainly focused on virological data to understand the current epidemiology of WPV1 in Pakistan during 2019–2022. Methods In total, 141 037 stool specimens from patients reported with acute flaccid paralysis and 3171 wastewater samples were tested for detection of poliovirus using cell culture and polymerase chain reaction (PCR). Phylogenetic analysis of WPV1 was performed using MEGA and Nextstrain. Results Poliovirus isolates were classified into 15 distinct genetic clusters with multiple transmission lineages. Spatiotemporal trends indicated a significant decline in the incidence of poliomyelitis, reported in 58 districts in 2019 and just 3 in 2022. The historical reservoirs in Peshawar, Quetta, and Karachi successfully eliminated the indigenous transmission chains of wild poliovirus that had been active there for years Conclusions Our findings reinforce the evolving epidemiology of poliovirus in Pakistan, which is now confined to south-KP. All historically known reservoirs in Peshawar, Karachi, and Quetta block are now free of poliovirus. Intensified clinical and environmental surveillance should be maintained to eliminate the very few remaining transmission lineages and certify poliovirus eradication by 2026.

中文翻译：

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2019-2022 年巴基斯坦历史库区 1 型野生脊髓灰质炎病毒的分子流行病学和变化


背景 巴基斯坦是 1 型野生脊髓灰质炎病毒 （WPV1） 流行的两个国家之一。积极的临床和环境废水监测以及实验室调查是脊髓灰质炎根除战略不可或缺的主要组成部分。目前的研究主要集中在病毒学数据上，以了解 2019-2022 年巴基斯坦当前 WPV1 的流行病学。方法 采用细胞培养和聚合酶链反应 （PCR） 检测 141 037 份急性弛缓性麻痹患者的粪便标本和 3171 份废水标本，用于脊髓灰质炎病毒的检测。使用 MEGA 和 Nextstrain 对 WPV1 进行系统发育分析。结果 脊髓灰质炎病毒分离株分为 15 个具有多个传播谱系的不同遗传簇。时空趋势表明脊髓灰质炎的发病率显着下降，2019 年有 58 个地区报告，2022 年仅 3 个地区报告。白沙瓦、奎达和卡拉奇的历史水库成功地消除了在那里活跃多年的野生脊髓灰质炎病毒的本土传播链 结论 我们的研究结果加强了巴基斯坦脊髓灰质炎病毒不断发展的流行病学，该流行病学现在仅限于南部 KP。白沙瓦、卡拉奇和奎达街区所有历史上已知的水库现在都没有脊髓灰质炎病毒。应继续加强临床和环境监测，以消除极少数剩余的传播谱系，并在 2026 年之前证明脊髓灰质炎病毒已根除。