Holding back the tiger: Successful control program protects Australia from Aedes albopictus expansion

Area of Science:

• Entomology
• Invasive Species Biology
• Public Health

Background:

• The Asian tiger mosquito (Aedes albopictus) is an invasive vector of significant arboviruses like dengue, chikungunya, and Zika.
• First detected in Australia in 2005 in the Torres Strait, control efforts initially aimed at elimination.
• Evolving management strategies were necessary due to the species' invasive nature and the challenges of eradication.

Purpose of the Study:

• To describe the evolution of Ae. albopictus management strategies in the Torres Strait.
• To provide a adaptable framework for Ae. albopictus control applicable to other regions.
• To assess the effectiveness of implemented control measures in preventing mainland establishment.

Main Methods:

• Initial larval control using source reduction and insecticides (insect-growth regulators, pyrethroids).
• Shifted to a quarantine strategy focusing on preventing spread to key transport islands (Thursday and Horn Islands).
• Incorporated harborage spraying of adult resting sites with residual pyrethroid insecticide and increased treatment frequency.

Main Results:

• The integrated strategy, including harborage spraying, led to a 97% decline in Ae. albopictus populations within two years.
• Populations on Thursday and Horn Islands became undetectable in 70-90% of surveys by 2015-2016.
• No established Ae. albopictus populations were detected on mainland Australia as of June 2016.

Conclusions:

• The revised vector management program successfully reduced local Ae. albopictus populations and prevented mainland establishment.
• The successful strategies offer a practical management framework for controlling arbovirus outbreaks transmitted by Ae. albopictus.
• The program demonstrates the feasibility of managing invasive mosquito populations and mitigating disease transmission risks.