A potential global surveillance tool for effective, low-cost sampling of invasive Aedes mosquito eggs from tyres using adhesive tape

Thom Dallimore,Sven Batke,David Goodson,Clare Strode

doi:10.1186/s13071-020-3939-0

Abstract

BackgroundThe international movement of used tyres is a major factor responsible for global introductions of Aedes invasive mosquitoes (AIMs) (Diptera: Culicidae) that are major disease vectors (e.g. dengue, Zika, chikungunya and yellow fever). Surveillance methods are restricted by expense, availability and efficiency to detect all life stages. Currently, no tested method exists to screen imported used tyres for eggs in diapause, the life stage most at risk from accidental introduction. Here we test the efficiency of adhesive tape as an affordable and readily available material to screen tyres for eggs, testing its effect on hatch rate, larval development, DNA amplification and structural damage on the egg surface.ResultsWe demonstrated that the properties of adhesive tape can influence pick up of dormant eggs attached to dry surfaces. Tapes with high levels of adhesion, such as duct tape, removed eggs with high levels of efficiency (97% ± 3.14). Egg numbers collected from cleaned used tyres were found to explain larval hatch rate success well, particularly in subsequent larval to adult emergence experiments. The strength of this relationship decreased when we tested dirty tyres. Damage to the exochorion was observed following scanning electron microscopy (SEM), possibly resulting in the high variance in the observed model. We found that five days was the optimal time for eggs to remain on all tested tapes for maximum return on hatch rate success. Tape type did not inhibit amplification of DNA of eggs from three, five or ten days of exposure. Using this DNA, genotyping of AIMs was possible using species-specific markers.ConclusionsWe demonstrated for the first time that adhesive tapes are effective at removing AIM eggs from tyres. We propose that this method could be a standardised tool for surveillance to provide public health authorities and researchers with an additional method to screen tyre cargo. We provide a screening protocol for this purpose. This method has a global applicability and in turn can lead to increased predictability of introductions and improve screening methods at high risk entry points.

Highlights

The international movement of used tyres is a major factor responsible for global introductions of Aedes invasive mosquitoes (AIMs) (Diptera: Culicidae) that are major disease vectors
There is currently no surveillance technique that screens for the presence of AIM eggs as a primary introduction route
Identification at this point is important as AIMs have proven to be biologically adaptive to new conditions and are successfully invasive in many areas around the world [19, 20]

Summary

Introduction

The international movement of used tyres is a major factor responsible for global introductions of Aedes invasive mosquitoes (AIMs) (Diptera: Culicidae) that are major disease vectors (e.g. dengue, Zika, chikungunya and yellow fever). Annual infection rates of DENV (family Flaviviridae) have been predicted at 284–528 million [1], resulting in ~ 20,000 reported deaths per year [2]. It is a Dallimore et al Parasites Vectors (2020) 13:91 multi-form disease with varying side effects and severity, symptoms range from flu-like fevers and a characteristic skin rash, to severe haemorrhagic bleeding and potentially fatal hypertension. Reasons for accelerated ZIKV are yet to be confirmed but are likely to be multi-causal with lack of localised immunity, increased mobility of competent vectors, delayed detection and expanding levels of globalisation the likely candidates [10, 11]

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Discussion

Conclusion