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.
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-
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
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.
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.
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 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
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