Jason Axford

Research OfficerJ Axford II
Bio21 Incubator Building
Room G18
+613 8344 2491
jkaxford@unimelb.edu.au

Biography:

I’m interested in the morphology, behaviour and life cycles of insects involved in disease transmission. I majored in Zoology and Genetics at Latrobe University, Bundoora and completed an Honours year in 2009 at the University of Melbourne developing skills in DNA sequence analysis and cloning techniques.

Since 2010 my research has focused on the prevention of arboviral disease transmission by mosquitoes, primarily species within the genus Aedes. My investigations of this genus have included the species A. aegypti, A. albopictus, A. notoscriptus and A. camptorhynchus. The first two species are major vectors of the Flaviviridae family of viruses, particularly DENV which causes Dengue Haemorrhagic Fever (DHF). An effective vaccine against DENV does not exist yet, however a naturally occurring Rickettsia-like, intracellular, endosymbiotic bacterium named Wolbachia pipientis has shown great potential as a disease control agent. Within its natural host W. pipientis can inhibit the growth of pathogenic arboviruses and these effects were also demonstrated within naïve hosts such as A. aegypti after being artificially infected via embryonic transfection. Conveniently, this maternally transmitted bacterium invades natural mosquito populations by inducing cytoplasmic incompatibility. However the invasion potential is counteracted by reductions in relative fitness due to the infection. My research upon A. aegypti aims to measure relative fitness parameters employed in models that predict the spread of these W. pipientis-infected mosquitoes once released into wild populations with the aim of identifying the strains most suited to collapsing disease transmission cycles. Respirometry techniques usually adapted to vertebrates have also been explored in measuring relative metabolic rates in mosquito eggs to inform these models. Future plans include extending these techniques to other vectors such as A. albopictus. By combining other tools such as species distribution modelling, I hope to provide the information required to reduce the economic burden that insect-borne diseases such as DHF cause.

Other Projects:

Whilst A. notoscriptus and A. camptorhynchus are known vectors of flaviviruses, alphaviruses and filarial nematodes they have also been implicated in the transmission of Mycobacterium ulercans, the etiological agent of Buruli ulcer. In collaboration with the Peter Doherty Institute we hope to replicate this experimentally but also determine the mode of transmission

Recent Publications (2010 – 2014):

Hoffmann, A.A. Iturbe-Ormaetxe, I. Callahan, A.G. Phillips, B.L. Billington K., Axford, J.K Montgomery, B. Turley, A.P. O’Neill, S.L. (2014). Stability of the wMel Wolbachia infection following invasion into Aedes aegypti populations. PLoS Neglected Tropical Diseases 8(9):e3115.

Yeap, H.L. Axford, J.K. Popovici, J. Endersby, N.M. Iturbe-Ormaetxe, I. Ritchie, S.A. Hoffmann, A.A. (2014). Assessing quality of life-shortening Wolbachia-infected Aedes aegypti mosquitoes in the field based on capture rates and morphometric assessments. Parasites and Vectors 7(1):58.

Hill, M.P. Axford, J.K. Hoffmann, A.A. (2014). Predicting the spread of Aedes albopictus in Australia under current and future climates: multiple approaches and data sets to incorporate potential evolutionary divergence. Austral Ecology 39:469-478.

Hoffmann, A.A. Montgomery, B.L. Popovici, J. Iturbe-Ormaetxe, I. Johnson, P.J. Muzzi, F. Greenfield, M. Durkan, M. Leong, Y.S.Dong, Y. Cook, H. Axford, J. K. Callahan, A.G. Kenny, N. Omodei, C. McGraw, E.A.  Ryan, P.A. Ritchie, S. Turelli, M. O’Neill, S.L. (2011).Successful establishment of Wolbachia in Aedes populations to suppress dengue transmission. Nature 476: 454-U107.

Walker, T. Johnson, P.H. Moreira, L.A. Iturbe-Ormaetxe, I. Frentiu, F.D. McMeniman, C.J. Leong, Y.S. Dong, Y. Axford, J. Kriesner, P. Lloyd, A.L. Ritchie, S.A. O’Neill, S.L. Hoffmann, A.A. (2011) the wMel Wolbachia strain blocks dengue and invades cagedAedes aegypti populations. Nature 476: 450-U101.

Lee, S.F. Chen, Y. Varen, A.K. Wee, C.W. Rako, L. Axford, J.K. Good, R.T. Blacket, M.J. Ruter, C. Partridge, L. Hoffmann, A.A. (2011). Molecular basis of adaptive shift in body size in Drosophila melanogaster: functional and sequence analyses of the Dcagene. Molecular Biology and Evolution 28: 2393-2402.

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