From Incriminating Stegomyia fasciata to Releasing Wolbachia pipientis: Australian Research on the Dengue Virus Vector, Aedes aegypti, and Development of Novel Strategies for Its Surveillance and Control

Andrew Van Den Hurk

doi:10.3390/tropicalmed3030071

Andrew Van Den Hurk

Open Access

https://doi.org/10.3390/tropicalmed3030071

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Abstract

Globally, the dengue viruses (DENVs) infect approximately 300 million people annually. Australia has a history of epidemic dengue, with outbreaks in the early decades of the twentieth century responsible for tens of thousands of cases. Seminal experiments conducted by Australian scientists during these outbreaks were the first to incriminate Aedes aegypti as a major vector of dengue viruses. One hundred years later, Australian scientists are playing a lead role in the development of surveillance and suppression strategies that target this mosquito species. Surveillance of Ae. aegypti populations and their associated dengue risk was greatly improved by understanding the contribution of key premises, key containers, and cryptic larval habitats to mosquito productivity, and, more recently, the development of novel adult traps. In terms of mosquito control, targeted indoor residual pyrethroid spraying and community-based biological control utilizing predatory copepods can significantly reduce Ae. aegypti populations. The release of Ae. aegypti transinfected with the virus-blocking bacterium, Wolbachia, provides a promising strategy for limiting DENV transmission. These diverse strategies developed by Australian scientists have the potential to alleviate the burden of dengue in the future, whether it is at the local level or as part of a country-wide program.

Highlights

Dengue viruses (DENVs) are single-stranded positive-sense RNA viruses globally responsible for an estimated 300 million infections annually [1]
Recent analyses conducted by Vazquez-Prokopec et al [54,58] on outbreaks of DENV-2 and DENV-3 in Cairns in 2003 and 2008–2009, respectively, revealed that targeted indoor residual spraying (TIRS) integrated with contact tracing of notified dengue cases and larval control can lead to a significant decrease in the probability of future DENV transmission
There was some spectacular success in eliminating Ae. aegypti, most notably in South and Central America during the middle of the 20th century [95], the ever-increasing global burden of DENVs indicates that elimination or larvicide treatment of containers, and indiscriminate application of adulticides are largely ineffective for sustained control of Ae. aegypti

Summary

Introduction

Dengue viruses (DENVs) are single-stranded positive-sense RNA viruses globally responsible for an estimated 300 million infections annually [1]. Due to the lack of a highly effective vaccine, the primary control strategy for dengue relies on mosquito suppression. This generally involves elimination of water-holding containers that support larval development, and/or application of insecticides targeting larvae and adults. The effectiveness of control strategies targeting Ae. aegypti and Ae. albopictus is compromised by the close association between these species and human habitation, which provides numerous containers for larval development, preferred human blood meals, and intradomiciliary feeding and resting sites. Due to the constant threat of DENVs, Australian scientists greatly contributed to the understanding of virus transmission cycles, and developed or refined strategies for Ae. aegypti surveillance and control that show considerable promise for DENV control in nations where these viruses exact their greatest toll. This paper revisits early Australian experiments conducted to incriminate Ae. aegypti as a DENV vector, fast forwards approximately 100 years to examine recent advances in our knowledge of Ae. aegypti biology and DENV control that Australian scientists performed a lead role in developing

Dengue in Australia

Evolution of Insecticide-Based Methodologies

Utilizing Wolbachia for Dengue Control

Findings

Conclusions and Future Perspectives