Romano Greta, Ferrari Guglielmo, Pitrolo Antonino Maria Guglielmo, Rovida Francesca, Piralla Antonio, Baldanti Fausto
Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy.
Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, 27100 Pavia, Italy.
Pathogens. 2024 Dec 19;13(12):1124. doi: 10.3390/pathogens13121124.
The dengue virus (DENV) is a mosquito-borne flavivirus endemic to many tropical and subtropical regions. Over the past few decades, the global incidence of dengue has risen dramatically, with the virus now present in over 100 countries, putting nearly half of the world's population at risk. This increase is attributed to several factors, including urbanization, climate change, and global travel, which facilitate the spread of both the virus and its mosquito vectors. While dengue is primarily associated with tropical regions, outbreaks in temperate areas are becoming increasingly common due to the spread of , a competent vector for DENV that can adapt to cooler climates. This study investigates the molecular dynamics and geographic evolution of DENV type 1 (DENV-1) strains isolated from 13 patients during an autochthonous outbreak in Lombardy, Northern Italy, between August and September 2023. Additionally, mosquitoes were collected from a neighboring area to assess their potential role in the outbreak. A metagenomic approach was used to recover DENV-1 consensus sequences from clinical samples. Genotype classification and phylogenetic analyses were performed using Bayesian methods and a comprehensive dataset of DENV-1 sequences from other countries. The Italian autochthonous strains clustered with South American strains collected between 2020 and 2023, specifically those belonging to genotype V, subtype D. Bayesian analysis estimated a mean evolutionary substitution rate of 8.234 × 10 substitutions per site per year (95% HPD interval: 7.1448 × 10-9.3343 × 10), with the time to the most recent common ancestor (tMRCA) dating back to 1972 (95% HPD interval: 1968-1976). These findings suggest the likely introduction of the virus into the region from endemic areas in South America, followed by local transmission. This study offers valuable insights into the dynamics of the DENV-1 outbreak in Lombardy, underscoring the importance of genomic surveillance in monitoring viral spread and evolution. The findings emphasize the critical need for enhanced molecular and entomological surveillance to detect and respond to emerging autochthonous DENV cases in temperate regions where competent vectors, such as , are present. Public health strategies should prioritize integrated vector management, real-time genomic monitoring, and awareness campaigns to mitigate the risk of future outbreaks. These measures are essential to address the growing threat posed by the geographic expansion of the dengue virus.
登革病毒（DENV）是一种由蚊子传播的黄病毒，在许多热带和亚热带地区流行。在过去几十年中，全球登革热发病率急剧上升，目前该病毒已在100多个国家出现，使全球近一半人口面临风险。这种增长归因于几个因素，包括城市化、气候变化和全球旅行，这些因素促进了病毒及其蚊子传播媒介的传播。虽然登革热主要与热带地区有关，但由于埃及伊蚊（一种能够适应较凉爽气候的DENV有效传播媒介）的传播，温带地区的疫情越来越普遍。本研究调查了2023年8月至9月期间在意大利北部伦巴第大区一次本地疫情中从13名患者分离出的1型登革病毒（DENV-1）毒株的分子动力学和地理进化情况。此外，还从邻近地区收集了埃及伊蚊，以评估它们在疫情中的潜在作用。采用宏基因组学方法从临床样本中获取DENV-1共识序列。使用贝叶斯方法和来自其他国家的DENV-1序列综合数据集进行基因型分类和系统发育分析。意大利本地毒株与2020年至2023年期间收集的南美毒株聚类，特别是那些属于基因型V、亚型D的毒株。贝叶斯分析估计平均进化替代率为每年每个位点8.234×10^-9次替代（95%最高后验密度区间：7.1448×10^-9 - 9.3343×10^-9），最近共同祖先时间（tMRCA）可追溯到1972年（95%最高后验密度区间：1968 - 1976）。这些发现表明该病毒可能从南美流行地区传入该地区，随后在当地传播。本研究为伦巴第大区DENV-1疫情的动态提供了有价值的见解，强调了基因组监测在监测病毒传播和进化中的重要性。研究结果强调了加强分子和昆虫学监测以检测和应对温带地区出现的本地DENV病例的迫切需求，在这些地区存在像埃及伊蚊这样的有效传播媒介。公共卫生策略应优先考虑综合媒介管理、实时基因组监测和宣传活动，以降低未来疫情爆发的风险。这些措施对于应对登革病毒地理扩张带来的日益增长的威胁至关重要。
