Study calculates costs of invasive mosquito arriving in Brisbane

A new study has calculated the costs of the Asian Tiger Mosquito taking hold in Brisbane. The analysis, led by QIMR Berghofer and the CSIRO, has found that quickly and thoroughly eradicating the mosquito would be far more cost effective than allowing it to become established.

The Asian Tiger Mosquito, or Aedes albopictus, is the most invasive mosquito in the world. Native to tropical and subtropical areas of Southeast Asia, it has already spread across Europe, the Americas, Africa and the Pacific.

It can transmit more than 20 disease-causing viruses, including Zika, dengue fever and chikungunya. It is also a highly aggressive biter and causes significant nuisance.

The mosquito currently exists in the Torres Strait, but authorities have prevented it from taking hold on mainland Australia. It can survive in cool climates, which means it could become established in Brisbane, Sydney and Melbourne if it took hold on the mainland.

Researchers from QIMR Berghofer Medical Research Institute and the CSIRO analysed the costs and benefits of responding to two separate, hypothetical scenarios.

Dr Jonathan Darbro from QIMR Berghofer’s Mosquito Control Laboratory said in the first scenario, authorities immediately stamped out a limited incursion of the Asian Tiger Mosquito in Brisbane.

“In this scenario, the mosquito was detected on a suburban block within the Brisbane City Council area,” Dr Darbro said.

“We assessed that a team of 33 people would be needed to quickly and completely stamp out this incursion. This includes flying down expert teams from North Queensland to assess the local area and spray any breeding habitats.

“We found that this response would cost between $1.1 and $1.7 million depending on how many houses in the area had to be treated.

“As well as the costs of this response, we also calculated the value of eradicating this highly invasive pest for maintaining our current outdoor lifestyle. We found that each dollar spent on eradicating the mosquito would produce a benefit of up to $78 per person in mosquito-free, outdoor time each year.”

The second scenario involved the Asian Tiger Mosquito taking hold in Brisbane.

“In this scenario, the mosquito couldn’t be eliminated, so we calculated the costs of dealing with it on an ongoing basis,” Dr Darbro said.

“This includes the costs of sending out mosquito control teams each time someone infected with Zika virus, dengue fever or chikungunya arrives in Brisbane from overseas. This response would be needed to stop the local mosquito population from contracting and spreading these diseases.

“It also includes the costs of dealing with extra phone calls to the Council and extra personnel to respond to mosquito complaints from the public.

“We estimated that this would cost between $650,000 and $1.5 million every year. However, these costs would be much higher if there was a serious outbreak of mosquito-borne disease.

“This study shows that any money spent eradicating the Asian Tiger Mosquito before it became endemic would be well worthwhile.”

CSIRO research director Dr Paul de Barro said the fact that the Asian Tiger Mosquito had failed to penetrate mainland Australia illustrated the strength of our national biosecurity measures.

“Australia has the enviable position of being free from many global pests and diseases because we have one of the strongest biosecurity systems in the world. However, we are under increasing pressure from biosecurity threats such as the Asian Tiger Mosquito as we become more connected to the world through trade and the increased movement of cargo and people,” he said.

“By calculating the substantial costs and effort associated with using traditional methods to stamp out an Asian Tiger Mosquito incursion, or to manage an outbreak, this research highlights the need for novel ways to suppress or eradicate invasive mosquitoes.”

Dr de Barro said that CSIRO was already working on a potential solution in northern Queensland with American life sciences company Verily.

“Our partnership with Verily as part of the global Debug project involves developing a Sterile Insect Technique (SIT) to suppress numbers of the Aedes Aegypti, another disease-spreading mosquito. This is the sort of innovative technology solution that will be required to ensure Australia has the capacity to respond to the possible emergence of Asian Tiger Mosquito, or other threats,” he said.

The study has been published in the journal Ecological Economics. It involved collaborators from the Metro South Hospital and Health Service and Brandeis University in the United States.

Media contacts

QIMR Berghofer:

Siobhan Barry: Siobhan.Barry@qimrberghofer.edu.au / 0458 650 200

CSIRO:

Ofa Fitzgibbons: ofa.fitzgibbons@csiro.au / 0424 031 639