Guagliardo Sarah Anne, Morrison Amy C, Barboza Jose Luis, Requena Edwin, Astete Helvio, Vazquez-Prokopec Gonzalo, Kitron Uriel
Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America.
Department of Entomology, University of California, Davis, Davis, California, United States of America.
PLoS Negl Trop Dis. 2015 Apr 10;9(4):e0003648. doi: 10.1371/journal.pntd.0003648. eCollection 2015 Apr.
The dramatic range expansion of the dengue vector Aedes aegypti is associated with various anthropogenic transport activities, but little is known about the underlying mechanisms driving this geographic expansion. We longitudinally characterized infestation of different vehicle types (cars, boats, etc.) to estimate the frequency and intensity of mosquito introductions into novel locations (propagule pressure).
Exhaustive adult and immature Ae. aegypti collections were performed on six different vehicle types at five ports and two bus/ taxi departure points in the Amazonian city of Iquitos, Peru during 2013. Aquatic vehicles included 32 large and 33 medium-sized barges, 53 water taxis, and 41 speed boats. Terrestrial vehicles sampled included 40 buses and 30 taxis traveling on the only highway in the region. Ae. aegypti adult infestation rates and immature indices were analyzed by vehicle type, location within vehicles, and sampling date.
Large barges (71.9% infested) and medium barges (39.4% infested) accounted for most of the infestations. Notably, buses had an overall infestation rate of 12.5%. On large barges, the greatest number of Ae. aegypti adults were found in October, whereas most immatures were found in February followed by October. The vast majority of larvae (85.9%) and pupae (76.7%) collected in large barges were produced in puddles formed in cargo holds.
Because larges barges provide suitable mosquito habitats (due to dark, damp cargo storage spaces and ample oviposition sites), we conclude that they likely serve as significant contributors to mosquitoes' propagule pressure across long distances throughout the Peruvian Amazon. This information can help anticipate vector population mixing and future range expansions of dengue and other viruses transmitted by Ae. aegypti.
登革热媒介埃及伊蚊显著的范围扩张与各种人为运输活动有关，但对于驱动这种地理扩张的潜在机制知之甚少。我们纵向描述了不同类型交通工具（汽车、船只等）的侵染情况，以估计蚊子引入新地点的频率和强度（繁殖体压力）。
2013年期间，在秘鲁亚马逊城市伊基托斯的五个港口和两个公交/出租车出发点，对六种不同类型的交通工具进行了详尽的成年和未成熟埃及伊蚊采集。水上交通工具包括32艘大型和33艘中型驳船、53艘水上出租车和41艘快艇。陆地交通工具样本包括在该地区唯一一条公路上行驶的40辆公交车和30辆出租车。按交通工具类型、交通工具内位置和采样日期分析了埃及伊蚊成虫侵染率和未成熟指标。
大多数侵染情况发生在大型驳船（71.9%被侵染）和中型驳船（39.4%被侵染）上。值得注意的是，公交车的总体侵染率为12.5%。在大型驳船上，10月份发现的埃及伊蚊成虫数量最多，而大多数未成熟个体在2月份被发现，其次是10月份。在大型驳船上采集的绝大多数幼虫（85.9%）和蛹（76.7%）是在货舱形成的水坑中产生的。
由于大型驳船提供了适宜的蚊子栖息地（由于黑暗、潮湿的货物储存空间和充足的产卵地点），我们得出结论，它们很可能是秘鲁亚马逊地区蚊子远距离繁殖体压力的重要贡献者。这些信息有助于预测登革热和其他由埃及伊蚊传播的病毒的媒介种群混合和未来范围扩张。
