Khan Jehangir, Adil Muhammad, Tsheten Tsheten, Manrique-Saide Pablo, Zhang Dongjing, Aziz Abdul, Lv Zhiyue, Chen Tao
Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China.
Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China.
PLoS Negl Trop Dis. 2025 Jul 22;19(7):e0013252. doi: 10.1371/journal.pntd.0013252. eCollection 2025 Jul.
Effective dengue management hinges on targeting key vector breeding sites and understanding transmission risks. Despite recurring outbreaks in Pakistan's Khyber Pakhtunkhwa (KP) Province since 2013, comprehensive entomological and virological data remain scarce. This study identified key larval-based indicators (habitats, Stegomyia indices), mosquito species composition, and dengue virus (DENV) infection rates in Aedes mosquitoes, evaluating their contributions to outbreak risk.
METHODOLOGY/PRINCIPAL FINDINGS: From July to December 2021, a cross-sectional larval survey of Aedes aegypti and Ae. albopictus was conducted across epidemiologically high-risk KP districts, inspecting water-holding containers located indoors, outdoors, and on rooftops. Additionally, adult mosquitoes were collected using aspirators and nets, with weekly dengue case data sourced from Peshawar's Directorate of Health Services. A subsample of 200 adult mosquito pools (20 per district) underwent RT-PCR to determine minimum infection rates (MIR). Larval indices revealed a House Index (HI) of 19.4%, a Container Index (CI) of 20.4%, and a Breteau Index (BI) of 89%. Aedes aegypti was the dominant species, accounting for 62% of larvae and 67.8% of adult mosquitoes. Peshawar (BI = 89.3), Nowshera (BI = 71.4), and Mardan (BI = 57) reported the highest Breteau indices and corresponding dengue case counts: 2,584 (48.8%), 404 (7.6%), and 327 (6.2%), respectively. The peak larval positivity was recorded in October (29.3%) and September (24.7%), aligning with dengue patient hospitalization rates of 52.8% and 46.8%, respectively. Common breeding sites included indoor flowerpots (25.4%), outdoor rubber tyres (16%), and roof tap water (23.7%). Container type and location significantly (P < 0.00) predicted larval abundance. Regression analysis revealed significant associations between dengue incidence, population density, and stegomyia indices. Of 38 positive pools (19%), DENV-2 and DENV-3 predominated (47.4% each), with peak MIRs recorded in Peshawar (30), Mardan (25), and Haripur (25).
CONCLUSIONS/SIGNIFICANCE: High larval indices and dual-serotype circulation in adaptable Aedes vectors signal substantial outbreak risk in KP. These findings underscore the need for targeted vector strategies, focusing on containers with the highest breeding potentials and epidemiological significance, particularly in high-transmission areas. Further molecular and entomological investigations are critical to corroborate these findings and inform more effective interventions.
有效的登革热防控取决于确定关键病媒滋生地并了解传播风险。自2013年以来，巴基斯坦开伯尔-普赫图赫瓦省（KP省）登革热疫情反复爆发，但全面的昆虫学和病毒学数据仍然匮乏。本研究确定了基于幼虫的关键指标（栖息地、白纹伊蚊指数）、蚊种组成以及埃及伊蚊中的登革病毒（DENV）感染率，评估它们对疫情风险的影响。
方法/主要发现：2021年7月至12月，在KP省疫情高发地区开展了一项埃及伊蚊和白纹伊蚊幼虫横断面调查，检查室内、室外和屋顶的蓄水容器。此外，使用吸蚊器和蚊帐收集成蚊，每周的登革热病例数据来自白沙瓦卫生局。对200个成蚊样本池（每个地区20个）的子样本进行逆转录聚合酶链反应（RT-PCR），以确定最低感染率（MIR）。幼虫指数显示房屋指数（HI）为19.4%，容器指数（CI）为20.4%，布雷图指数（BI）为89%。埃及伊蚊是优势种，占幼虫的62%和成蚊的67.8%。白沙瓦（BI = 89.3）、瑙谢拉（BI = 71.4）和马尔丹（BI = 57）的布雷图指数最高，相应的登革热病例数分别为2584例（48.8%）、404例（7.6%）和327例（6.2%）。幼虫阳性率高峰出现在10月（29.3%）和9月（24.7%），分别与登革热患者住院率52.8%和46.8%一致。常见的滋生地包括室内花盆（25.4%）、室外橡胶轮胎（16%）和屋顶自来水（23.7%）。容器类型和位置显著（P < 0.00）预测幼虫数量。回归分析显示登革热发病率、人口密度和白纹伊蚊指数之间存在显著关联。在38个阳性样本池（19%）中，DENV-2和DENV-3占主导（各占47.4%），白沙瓦（30）、马尔丹（25）和哈里普尔（25）的最低感染率最高。
结论/意义：适应性强的埃及伊蚊幼虫指数高且双血清型循环表明KP省存在重大疫情风险。这些发现强调需要采取针对性的病媒控制策略，重点关注滋生潜力和流行病学意义最高的容器，特别是在高传播地区。进一步的分子和昆虫学调查对于证实这些发现并为更有效的干预措施提供依据至关重要。
