Towards environmental detection, quantification, and molecular characterization of Anopheles stephensi and Aedes aegypti from experimental larval breeding sites

Abstract

The invasion and establishment of An. stephensi mosquitoes in the Horn of Africa represents a significant regional threat, which may jeopardise malaria control, particularly in urban areas which were formally free from disease transmission. Novel vector surveillance methods are urgently needed, both agnostic to mosquito larval morphology, and simple to implement at the sampling stage. Using new multiplex TaqMan assays, specifically targeting An. stephensi and Ae. aegypti, we validated the use of environmental DNA (eDNA) for simultaneous vector detection in shared artificial breeding sites. Study findings demonstrated that An. stephensi and Ae. aegypti eDNA deposited by as few as one second instar larva in 1L of water was detectable. Characterization of molecular insecticide resistance mechanisms, using novel amplicon-sequencing panels for both vector species, was possible from eDNA shed by as few as 16–32 s instar larvae in 50 ml of water. An. stephensi eDNA, derived from emergent pupae for 24 h, was remarkably stable, and still detectable ~ 2 weeks later. eDNA surveillance has the potential to be implemented in local endemic communities and at points of country entry, to monitor the spread of invasive vector species. Further studies are required to validate the feasibility of this technique under field conditions.

The Mosquito Fauna of Arizona: Species Composition and Public Health Implications

“…The same applies to anopheline species, where, e.g., CDC light traps [ 158 ] and Mosquito Magnet Patriot Mosquito traps [ 159 ] may be more effective in capturing this genus. In addition, other entomological indicators that can be used to guide vector control, such as (i) larval habitat preference (assessed through, e.g., larval dipping [ 160 ] or the use of environmental DNA [ 161 ]), (ii) indoor resting densities (assessed through, e.g., indoor resting collections and window exit traps), and (iii) the time of mosquito activity (assessed through, e.g., hourly switching of collection nets or rotator traps) are better assessed using different sampling methods [ 160 ]. Using the appropriate mosquito sampling methods in surveillance programs will ensure that the obtained data are reliable and relevant for public health decision-making, by identifying the appropriate control tools to optimally target vectors of medical importance [ 162 ].…”

A regional One Health approach to the risk of invasion byAnopheles stephensiin Mauritius

“…Proactive approaches are recommended, including the operational use of new surveillance tools, such as xenomonitoring based on saliva analysis (Flies et al ., 2015) or faeces analysis (Meyer et al ., 2019) of mosquitoes collected in integrated trapping systems, or the development of diagnostics based on e-DNA (Kristan et al ., 2023), or artificial intelligence algorithms for automated species recognition (e.g., Minakshi et al ., 2020ab). Genotyping using new population genomics techniques (as high-resolution genetic markers, single nucleotide polymorphisms (SNPs)) can be undertaken to identify the origin of insects and dispersal pathways by comparing the genotype of incursion samples to reference samples of known origin (Schmidt et al ., 2021).…”

“…Meyer et al, 2019) of mosquitoes collected in integrated trapping systems, or the development of diagnostics based on e-DNA(Kristan et al, 2023), or artificial intelligence algorithms for automated species recognition (e.g.,Minakshi et al, 2020ab). Genotyping using new population genomics techniques (as high-resolution genetic markers, single nucleotide polymorphisms (SNPs)) can be undertaken to identify the origin of insects and dispersal pathways by comparing the genotype of incursion samples to reference samples of known origin(Schmidt et al, 2021).Another recent development to improve the capacity to detect and monitor the spread of an invasive mosquito within a country is citizen science, where members of the public actively contribute to surveillance.…”