Montgomery Brian L, Shivas Martin A, Hall-Mendelin Sonja, Edwards Jim, Hamilton Nicholas A, Jansen Cassie C, McMahon Jamie L, Warrilow David, van den Hurk Andrew F
Metro South Public Health Unit, Queensland Health, Coopers Plains, Queensland, Australia.
Mosquito and Pest Management, Brisbane City Council, Fortitude Valley, Queensland, Australia.
PLoS Negl Trop Dis. 2017 Mar 24;11(3):e0005505. doi: 10.1371/journal.pntd.0005505. eCollection 2017 Mar.
The globally important Zika, dengue and chikungunya viruses are primarily transmitted by the invasive mosquitoes, Aedes aegypti and Aedes albopictus. In Australia, there is an increasing risk that these species may invade highly urbanized regions and trigger outbreaks. We describe the development of a Rapid Surveillance for Vector Presence (RSVP) system to expedite presence- absence surveys for both species.
METHODOLOGY/PRINCIPAL FINDINGS: We developed a methodology that uses molecular assays to efficiently screen pooled ovitrap (egg trap) samples for traces of target species ribosomal RNA. Firstly, specific real-time reverse transcription-polymerase chain reaction (RT-PCR) assays were developed which detect a single Ae. aegypti or Ae. albopictus first instar larva in samples containing 4,999 and 999 non-target mosquitoes, respectively. ImageJ software was evaluated as an automated egg counting tool using ovitrap collections obtained from Brisbane, Australia. Qualitative assessment of ovistrips was required prior to automation because ImageJ did not differentiate between Aedes eggs and other objects or contaminants on 44.5% of ovistrips assessed, thus compromising the accuracy of egg counts. As a proof of concept, the RSVP was evaluated in Brisbane, Rockhampton and Goomeri, locations where Ae. aegypti is considered absent, present, and at the margin of its range, respectively. In Brisbane, Ae. aegypti was not detected in 25 pools formed from 477 ovitraps, comprising ≈ 54,300 eggs. In Rockhampton, Ae. aegypti was detected in 4/6 pools derived from 45 ovitraps, comprising ≈ 1,700 eggs. In Goomeri, Ae. aegypti was detected in 5/8 pools derived from 62 ovitraps, comprising ≈ 4,200 eggs.
CONCLUSIONS/SIGNIFICANCE: RSVP can rapidly detect nucleic acids from low numbers of target species within large samples of endemic species aggregated from multiple ovitraps. This screening capability facilitates deployment of ovitrap configurations of varying spatial scales, from a single residential block to entire suburbs or towns. RSVP is a powerful tool for surveillance of invasive Aedes spp., validation of species eradication and quality assurance for vector control operations implemented during disease outbreaks.
全球范围内重要的寨卡病毒、登革热病毒和基孔肯雅病毒主要通过入侵性蚊子埃及伊蚊和白纹伊蚊传播。在澳大利亚，这些物种入侵高度城市化地区并引发疫情的风险日益增加。我们描述了一种用于媒介存在情况的快速监测（RSVP）系统的开发，以加快对这两种蚊子的存在与否调查。
方法/主要发现：我们开发了一种方法，利用分子检测技术有效地筛选混合的诱蚊产卵器（集卵器）样本，以检测目标物种核糖体RNA的痕迹。首先，开发了特异性实时逆转录聚合酶链反应（RT-PCR）检测方法，分别在含有4999只和999只非目标蚊子的样本中检测到单只埃及伊蚊或白纹伊蚊一龄幼虫。使用从澳大利亚布里斯班获得的诱蚊产卵器样本，对ImageJ软件作为自动计数工具进行了评估。在自动化之前，需要对诱蚊产卵纸条进行定性评估，因为在评估的44.5%的诱蚊产卵纸条上，ImageJ无法区分伊蚊卵与其他物体或污染物，从而影响了计数的准确性。作为概念验证，在布里斯班、罗克汉普顿和古默里对RSVP进行了评估，这三个地点分别被认为不存在、存在和处于埃及伊蚊分布范围的边缘。在布里斯班，从477个诱蚊产卵器收集的卵形成的25个样本池中未检测到埃及伊蚊，这些诱蚊产卵器包含约54300枚卵。在罗克汉普顿，从45个诱蚊产卵器收集的卵形成的6个样本池中，有4个检测到埃及伊蚊，这些诱蚊产卵器包含约1700枚卵。在古默里，从62个诱蚊产卵器收集的卵形成的8个样本池中，有5个检测到埃及伊蚊，这些诱蚊产卵器包含约4200枚卵。
结论/意义：RSVP可以快速从多个诱蚊产卵器收集的大量本地物种样本中检测到少量目标物种的核酸。这种筛查能力便于部署不同空间尺度的诱蚊产卵器配置，从单个住宅区到整个郊区或城镇。RSVP是监测入侵伊蚊物种、验证物种根除以及在疾病暴发期间实施的媒介控制行动质量保证的有力工具。
