Mosquito Control

There are no effective vaccines against malaria or most arboviruses. There are no chemotherapeutants for the treatment of arbovirus infection. Mosquito surveillance, management and manipulation remain the mainstays of most mosquito-borne disease control programs.  The Mosquito Control Laboratory (MCL) manages state-of-the art pathogen and insect containment facilities with the capacity to undertake studies on all aspects of vector biology and disease transmission. We work on innovations in mosquito surveillance and control that might help interrupt parasite and pathogen transmission.

We are unique in the Southern Hemisphere with regard to our size, capacity and expertise. This makes us a key partner in a national, regional and international network. Our presence significantly enhances Australia’s ability to investigate emerging vector-borne disease threats in the region. A major remit of the refurbished (2013), MCL is to exploit this unique facility through building strong collaborative links with parasitology, virology and vector biology laboratories throughout the world.

The MCL has permission to hold a number of exotic mosquito species in addition to native Australian mosquitoes. These include insecticide-resistant and susceptible Aedes aegypti strains, Aedes albopictus and Anopheles stephensi. The MCL has local access to real-world mosquito-virus transmission systems through a number of native mosquito vectors and their associated alphaviruses (including Ross River and Barmah Forest). We have field work in progress in Asia, Europe and the Americas.

CURRENT RESEARCH

  • vectorial capacity (the ability of mosquitoes to transmit disease)
  • Aedes-borne diseases (dengue, Zika, chikungunya)
  • Ross River virus transmission pathways and risks
  • use of the bacterium Wolbachia to control mosquito populations and reduce disease transmission
  • new insecticidal approaches to mosquito control: spatial repellents and auto-dissemination
  • treatment of domestic animals with endectocides for malaria control
  • novel surveillance tools (smart traps, genomics and Near Infra-Red Spectroscopy)
  • mosquito invasion risks – exotic species, invasion pathways and potential costs
  • mosquito genomics – population dynamics and structure of disease vectors

 

RESEARCH HIGHLIGHTS

  • The discovery of CRISPR-based gene editing and its application to homing-based gene drive systems has been greeted with excitement as it has the potential to control mosquito-borne diseases on a wide scale. Such technologies are also of concern, because of the potential invasiveness and irreversible establishment of released organisms. Here we explore a hypothetical release of two recently engineered threshold-dependent gene drive systems—reciprocal chromosomal translocations and a form of toxin-antidote-based under-dominance known as UDMEL to explore their ability to be confined and remediated. We simulated releases of Aedes aegypti, the mosquito vector of dengue, Zika, and other arboviruses, in Cairns, Australia, where previous releases of this species have taken place and where detailed data on their subsequent dispersal and establishment exists. We used these simulations to model the spread and establishment of mosquitoes carrying gene drive systems and assessed the ease of invasion and establishment, the probability that they could be contained within the release areas, and the potential for remediation or reversal of the release. Refer to Image 1 below.

Sánchez HM, Bennett JB, Wu SL, Rašić G, Akbari OS, Marshall JM (2020) Confinement and reversibility of threshold-dependent gene drive systems in spatially-explicit Aedes aegypti populations. BMC Biology 18: 50 https://doi.org/10.1186/s12915-020-0759-

  • Many arboviruses of public health significance are maintained in zoonotic cycles with complex transmission pathways that we are struggling to define. Standard serological surveys in potential virus reservoirs such as wild mammals, birds and domestic animals provides evidence of their exposure to disease but these surveys are difficult to conduct and they tell us nothing about the mosquito vector responsible for transmission. We developed a novel approach for screening the immune status of vertebrates against Ross River virus (RRV) by looking at the antibodies present in mosquito blood meals. This “flying syringe” technique is helping us to establish which vectors and vertebrate hosts are likely to be involved in the transmission cycles of RRV; Australia’s most commonly notified arboviral disease. Refer to Image 2 below.

Gayawali N, Murphy AK, Hugo L, Devine G (2020) A micro-PRNT for the detection of Ross River virus antibodies in mosquito blood meals: A useful tool for inferring transmission pathways. PLoS ONE 15(7): e0229314. https://doi.org/ 10.1371/journal.pone.0229314

  • Coastal development is expanding globally in response to mass human migration, yet urban planning guidelines in South East Queensland often overlook the problems that human encroachment on or near coastal mosquito habitat may cause. This study showed that the primary saltmarsh mosquitoes Aedes vigilax and Culex sitiens disperse from offshore breeding sites to neighbouring mainland areas in high numbers and in highly synchronized waves despite unfavourable wind patterns and the need to traverse a considerable expanse (ca. 1.4 km) of open water. These observations highlight the need to develop new planning and regulatory guidelines that alert urban planners to the risks of encroaching on habitats close to sources of highly vagile mosquito species

Johnson, B.J., Manby, R. & Devine, G.J. What Happens on Islands, doesn’t Stay on Islands: Patterns of Synchronicity in Mosquito Nuisance and Host-Seeking Activity between a Mangrove Island and Adjacent Coastal Development. Urban Ecosyst (2020). https://doi.org/10.1371/journal.pone.0229314  Refer to Image 3 below.

  • Flaviviruses, including Zika virus (ZIKV), utilise host mRNA degradation machinery to produce subgenomic flaviviral RNA (sfRNA). In mammalian hosts, this noncoding RNA facilitates replication and pathogenesis of flaviviruses by inhibiting IFN-signalling, whereas the function of sfRNA in mosquitoes remains largely elusive. We conducted a series of in vitro and in vivo experiments to define the role of ZIKV sfRNA in infected Aedes aegypti by using viruses deficient in production of sfRNA. We show that they had reduced ability to disseminate and reach the salivary glands. This is because sfRNA prevents cell death (apoptosis) in mosquito tissues and permits the  amplification and spread  of the virus

Slonchak, A., Hugo, L.E., Freney, M.E. et al. Zika virus noncoding RNA suppresses apoptosis and is required for virus transmission by mosquitoes. Nat Commun 11, 2205 (2020). https://doi.org/10.1038/s41467-020-16086-y Refer to Image 4 below.

Staff

PhD Candidates

  • Ms Lisa Rigby (University of Queensland, with Nigel Beebe). Insecticide resistance adaptations and implications for the transmission of vector-borne disease
  • Ms Carla da Silva Pessoa Vieira (Queensland University of Technology, with Francesca Frentiu). Ross River Virus ecology, phylogeny and genomics
  • Ms Amanda Murphy (Queensland University of Technology, with Francesca Frentiu). Exploring the determinants of Ross River virus (RRV) epidemics in SE Queensland
  • Mr Hasan Mohammad Al-Amin (University of Queensland, with Nigel Beebe). New tools for managing Aedes-borne diseases in Bangladesh
  • Mr Igor Filipovic (University of Queensland, with Michael Furlong). Long-read sequencing of a single-insect and its haploid cells: an approach to obtain high-quality genome assemblies in insect pests

PhD Candidates (Recently Graduated)

  • Dr Chen Wu (University of Queensland). Biology of natural Wolbachia infections in Australian mosquito species. Chen now works for BGI Australia
  • Dr Omezie Ekwudu (Queensland University of Technology). Dengue transmission in Australian populations of Aedes aegypti and Ae albopictus. Omezie works at QUT
  • Dr Brendan Trewin (University of Queensland). Invasion pathways for exotic mosquitoes. Brendan is currently a post-doctoral fellow at CSIRO
  • Dr Silvia Ciocchetta (Queensland University of Technology). Public health risks posed by Aedes koreicus. Silvia is now a veterinary researcher at the University of Queensland
  • Dr Jill Ulrich (University of Miami). Forecasting the future of mosquito-borne disease control. Jill is now a post-doctoral researcher at the University of Queensland

External Collaborators

  • Andrew van den Hurk, Queensland Forensic and Scientific Services
  • Dr Nigel Beebe, University of Queensland
  • Brendan Trewin, CSIRO
  • Dr John Marshall, University of California
  • Dr Richard Paul & Dr Louis Lambrechts, Institut Pasteur
  • Wenjin Liu, Australian Defence Force Malaria & Infectious Disease Institute (ADFMIDI)
  • Dr Chris Peatey, Australian Defence Force Malaria & Infectious Disease Institute (ADFMIDI)
  • Dr Tom Churcher, Imperial College, UK
  • Dr Francesca Frentiu, Queensland University of Technology
  • Professor John Aaskov, Queensland University of Technology
  • Dr Chanditha Hapuarachchi, National Environment Agency, Singapore
  • Dr Van-Mai Cao-Lormeau, Institut Louis Malarde
  • Professor Pablo Manrique-Saide, Universidad Autonoma de Yucatan
  • Dr Tedjo Sasmono, Eijkman Institute of Molecular Biology, Indonesia
  • Dr Gissella Vasquez, US Navy Medical Research Detachment-6, Peru
  • Dr Gonzalo Vasquez Prokopec, School of Environmental Sciences, Emory, USA
  • Dr Tangking Widarsa, Universitas Warmadewa, Indonesia
  • Dr Laith Yakob, London School of Hygiene and Tropical Medicine
  • The WIN network (https://win-network.ird.fr/)
  • The Mosquito and Arbovirus Research Committee (http://www.marc.net.au/

We have a broad funding base that includes local and federal government, the Australian NHMRC, the US Department of Defence, USAID, the Wellcome Trust and the UK Medical Research Council. We have won approximately $5.5M AUD in funding since 2013.

IMAGE GALLERY

Image 1. The discovery of CRISPR-based gene editing and its application to homing-based gene drive systems has been greeted with excitement as it has the potential to control mosquito-borne diseases on a wide scale. Such technologies are also of concern, because of the potential invasiveness and irreversible establishment of released organisms. Here we explore a hypothetical release of two recently engineered threshold-dependent gene drive systems—reciprocal chromosomal translocations and a form of toxin-antidote-based under-dominance known as UDMEL to explore their ability to be confined and remediated. We simulated releases of Aedes aegypti, the mosquito vector of dengue, Zika, and other arboviruses, in Cairns, Australia, where previous releases of this species have taken place and where detailed data on their subsequent dispersal and establishment exists. We used these simulations to model the spread and establishment of mosquitoes carrying gene drive systems and assessed the ease of invasion and establishment, the probability that they could be contained within the release areas, and the potential for remediation or reversal of the release.

Sánchez HM, Bennett JB, Wu SL, Rašić G, Akbari OS, Marshall JM (2020) Confinement and reversibility of threshold-dependent gene drive systems in spatially-explicit Aedes aegypti populations. BMC Biology 18: 50 https://doi.org/10.1186/s12915-020-0759-9

Image 2. Many arboviruses of public health significance are maintained in zoonotic cycles with complex transmission pathways that we are struggling to define. Standard serological surveys in potential virus reservoirs such as wild mammals, birds and domestic animals provides evidence of their exposure to disease but these surveys are difficult to conduct and they tell us nothing about the mosquito vector responsible for transmission. We developed a novel approach for screening the immune status of vertebrates against Ross River virus (RRV) by looking at the antibodies present in mosquito blood meals. This “flying syringe” technique is helping us to establish which vectors and vertebrate hosts are likely to be involved in the transmission cycles of RRV; Australia’s most commonly notified arboviral disease.

Gayawali N, Murphy AK, Hugo L, Devine G (2020) A micro-PRNT for the detection of Ross River virus antibodies in mosquito blood meals: A useful tool for inferring transmission pathways. PLoS ONE 15(7): e0229314. https://doi.org/ 10.1371/journal.pone.0229314

Image 3. Coastal development is expanding globally in response to mass human migration, yet urban planning guidelines in South East Queensland often overlook the problems that human encroachment on or near coastal mosquito habitat may cause. This study showed that the primary saltmarsh mosquitoes Aedes vigilax and Culex sitiens disperse from offshore breeding sites to neighbouring mainland areas in high numbers and in highly synchronized waves despite unfavourable wind patterns and the need to traverse a considerable expanse (ca. 1.4 km) of open water. These observations highlight the need to develop new planning and regulatory guidelines that alert urban planners to the risks of encroaching on habitats close to sources of highly vagile mosquito species.

Johnson, B.J., Manby, R. & Devine, G.J. What Happens on Islands, doesn’t Stay on Islands: Patterns of Synchronicity in Mosquito Nuisance and Host-Seeking Activity between a Mangrove Island and Adjacent Coastal Development. Urban Ecosyst (2020). https://doi.org/10.1371/journal.pone.0229314

Image 4. Flaviviruses, including Zika virus (ZIKV), utilise host mRNA degradation machinery to produce subgenomic flaviviral RNA (sfRNA). In mammalian hosts, this noncoding RNA facilitates replication and pathogenesis of flaviviruses by inhibiting IFN-signalling, whereas the function of sfRNA in mosquitoes remains largely elusive. We conducted a series of in vitro and in vivo experiments to define the role of ZIKV sfRNA in infected Aedes aegypti by using viruses deficient in production of sfRNA. We show that they had reduced ability to disseminate and reach the salivary glands. This is because sfRNA prevents cell death (apoptosis) in mosquito tissues and permits the  amplification and spread  of the virus.

Slonchak, A., Hugo, L.E., Freney, M.E. et al. Zika virus noncoding RNA suppresses apoptosis and is required for virus transmission by mosquitoes. Nat Commun 11, 2205 (2020). https://doi.org/10.1038/s41467-020-16086-y